The Philippine Electronics Code Volume 1 (Safety)

8/10/2019 The Philippine Electronics Code Volume 1 (Safety)

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THE PHILIPPINE ELECTRONICS CODE

1

I. GENERAL RULES

1.1 PURPOSE OF RULES

1.2 APPLICABITY OF RULES

1.2.1 CONSTRUCTION AND RECOSNTRUCTION

A. SERVICE DROP

B. SUBORDINATE ELEMENT

C. REPLACEMENT

1.2.2 MAINTENANCE OF PLANT

1.2.3 CONSTRUCTION PRIOR TO THIS CODE

1.2.4 RECONSTRUCTION OR ALTERATION

1.3 SCOPE OF RULES

1.4 EQUIVALENTS

1.5 LIMITING CONDITIONS REQUIRED

1.6 EXEMPTIONS OR MODIFICATIONS

1.7 SAVINGS


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SECTION I

GENERAL RULES

1.1

PURPOSE OF RULES

The primary purpose of these rules is to establish, for the Republic of Philippines, uniform standards,

regulations and requirements for Electronics and Communications Design, planning manufacture,

production, fabrication, construction, installation, operation, and maintenance, the application of which

will insure adequate protection and safety to persons therein engaged and as well as in the provision,

operation and use of electronics and or communications components, devices, equipment, systems, plants,

stations, services, and or facilities. Application of the rules will also establish an acceptable level of

protection for electronics and communication devices, equipment, and plant from damages due to

electrical and/or physical hazards.

1.2APPLICABILITY OF RULES

These rules apply to all electronics and/or communications design, planning, construction,

installation, manufacture, production, fabrication, operation, and maintenance, which comes within the

jurisdiction of this Code, located indoor or outdoor, terrestrially or extra terrestrially.

1.2.1

Construction and Reconstruction

The requirements apply to all devices, equipment, and plant constructed hereafter and shall become

applicable also to such components, equipment, devices, stations, plants, facilities, system and/or services

now existing, or any portion thereof whenever they are reconstructed.

The reconstruction of an element of a plant, station, system, or service requires that all elements

subordinate to the reconstructed element meet the requirements of these rules.

For the purpose of this Code, reconstruction will be constructed to mean that work which in any way

changes the identity of the station or plant or which it is performed excepting:

A. Service Drop

Service drops may be added to existing plant without necessitating changes in the circuit for

which they are originated.

B.

Subordinate El ement

An element added to an existing plant shall meet all requirements of these rules but does not

require any change in like elements already existing except where the added element is related to

existing like element. The plant or structure to which any subordinate element is added shall meet the

strength/safety factor.


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C. Replacements

Replacement of poles, towers, structure, or supports is considered to be reconstruction and

requires adherence to all strength and protection of this Code.

1.2.2

Maintenance of Plant

The plant or station shall be maintained in such condition to provide safety levels not less than the

minimum specified in rule 4.3.3. The plant or station, or portions thereof, constructed on or after the

effective date of this Code shall be kept in conformity with the requirements thereof.

The restoration of clearance and protection levels originally establish prior to the effective date of this

Code, where the original clearance or protection has been reduce by additional sagging or other causes, is

not considered reconstruction and the reestablish clearance or protection shall not be less than the original

clearance or protection at the time the plant or station was established. The changing of clearance or

protection for any other purpose is reconstruction and clearances or protection so changed shall comply

with the rules of this Code applicable to reconstruction.

1.2.3

Construction prior to the Code

The requirement of this Code, other than the requirement specified in Rules 1.2.2 and 1.2.4 do not

apply to plant or station constructed or reconstructed prior to the effective date of this Code. In all other

particulars, such plant or station or portions thereof shall conform to the requirements of the rules in effect

at the time of their construction or re-construction.

1.2.4 Reconstruction or Alternation

The Commission thru the appropriate government instrumentalities may order reconstruction or

alteration of existing plant or station or portions thereof whenever strength and electrical protection

requirement of this Code are not met and when public interest so requires.

1.3

SCOPE OF RULES

These rules are not intended as complete construction specifications, but embody only the

requirements which are most important from the standpoint of safety and protection. Construction shall be

according to accepted or established good practices for the given local conditions in all particulars not

specified in the rules.

1.4

EQUIVALENTS

Wires sizes specified in this Code may be substituted with its nearest metric equivalent. Copper wiremay be substituted with aluminum, copper clad steel, or other make/materials provided the current-

carrying capacity is identical.

Flat or braided copper may be substituted for round or stranded copper wire provided the current-

carrying capacity is not less than that of the latter.


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1.5

LIMITING CONDITIONS SPECIFIED

The requirement specified in these rules as to clearance, strength and protection are limiting

conditions expressed as minimum or maximumvalues, as indicated. In cases where two or more

requirements establish limiting conditions, the more or most stringent condition shall apply, thus

providing compliance with other applicable conditions. Greater strength of construction, more ample

clearances and higher protection level may be desirable or practical in some cases, and may be provided

accordingly if other requirements are not violated in so doing.

1.6

EXEMPTIONS MODIFICATIONS

If in a particular temporary and emergency case wherein a special type of construction, exemption

from or modification of any of the requirements herein is desired, the Commission shall consider an

application for such exemption or modification only when accompanied by a full statement of conditions

existing and the reason why such exemption or modification is asked and is believed to be justifiable. It is

to be understood that unless otherwise ordered, any exemption or modification so granted shall be limited

to the particular case or the special type of construction specifically covered by the application.

1.7SAVING CLAUSE

The Commission reserves the right to change any of the provisions of this Code in specific cases

when, in the Commissionsopinion, public interest shall be served by so doing.

Compliance with these rules and regulations shall not relieve a utility firm, entity, person or group of

persons from compliance with any statutory requirement.


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SECTION II

DEFINITIONS OF TERMS AS USED IN THE RULES

OF THIS CODE

This section defines technical terms as used in the rules of this Code. The meanings of some terms differ

with the field in which they are used, thus requiring more than one definition. Definitions contained in

this section have been restrictively worded to emphasize the special purpose they are used in this Code.

ACCESS

ACCESIBLE

ACCESSIBLE PART

ACCESSORIES

ACOUSTICS

ACOUSTIC SHOCK

AGING

AIR GAP

ALARM

ALIVE

ALPETH

A point of entry or a means of entry into a circuit.

Admitting close approach because not guarded by locked

doors, elevation or other effective means.

A part so located that it can be contacted by a person, either

directly or by means of a probe or tool, or that is not

recessed the required distance behind an opening.

Devices that performs a secondary or minor duty as an

adjunct or refinement to the primary or major duty of unit

of equipment.

The science of sound.

The physical pain, dizziness, and sometimes nausea caused

by hearing a sudden very loud sound. The threshold of painis about 120 dBm.

The changes in properties of a material in time.

A separating space between two magnetic materials or

conductors.

A visual or audible signal which alerts personnel to the

existence of an abnormal condition.

To have an electrical potential or charge different from that

to earth.

A type of telephone cable sheath featuring a corrugated

aluminum tape applied longitudinally and a polyethylene

jacket overall.


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AMERICAN WIRE GAUGE

(AWG)

AMPERE-HOUR

ANCHOR

ANHYDROUS

ANTENNA

APPLIANCE

ARRESTER

ARRESTER GAS-FILLED

ASSEMBLY

ATMOSPHERE,

EXPLOSIVE

ATTACHMENTS

AUDIO

AUTOMATIC

A scale of cross sectional measurement for non-ferrous

(copper, bronze, aluminum, etc.) wires.

The quantity of electricity represented by a current of one

ampere that flows for one hour.

Any device which holds something secure; a device buried

in the ground to which anchor rods and guys are fastened.

Dry; containing no water.

A means for radiating or receiving radio waves.

Any device that uses or needs electrical or usually an

electric current supply to perform a certain function or

operation; any equipment, usually complete in itself, that

transforms electric energy into another form usually aural,

visual, heat, or motion at the point of utilization.

Device which diverts high transient voltage to ground and

away from the equipment thus protected; the voltage

limiting portion of a protector.

Protector consisting of opposing spaced metal electrodes

within a sealed tube or enclosure filled with gas such as

neon or argon.

A grouping of components to accomplish a particular

function.

Air holding in suspension dust, metal particles of

flammable gas in such proportions that may ignite

explosively.

All of the plant elements (cables, cross-arms, brackets, etc.)

which are fastened to a supporting structure such as a pole.

Pertaining to frequencies which can be heard by the human

ear.

Describing the actions of a device or equipment which are

taken without human supervision in response to certain to

pre-determined conditions.


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BACKBONE

BANDWIDTH

BASEBAND

BATTERY

BOND

BUS

CABLE

CIRCUIT

CLIMBING SPACE

CONDUCTOR

COMMUNICATION

The main system route, usually the route carrying the

majority of the traffic, ad often the longest series of

cascaded hops.

Range of frequencies of a device, within which its

performance, in respect to some characteristics conform tosome specified limits; the difference between the upper and

lower limits of the operating frequency of the device.

Band of frequencies occupied by aggregate of all the

information signals use to modulate a carrier.

A group of two or more cells connected together to furnish

current by conversion of chemical, thermal, solar or nuclear

energy into electrical energy. Common usage permits this

designation to be applied also to a single cell.

A low resistance electrical connection between two cable

sheets, between two ground connections or between similar

parts of two circuits.

A conductor or group of conductors, that serves as a

common connection for two or more circuits.

Assembly of insulated conductors into a compact form

which is covered by a flexible, waterproof, protective

covering.

(1) The complete electrical path between terminals over

which telecommunications are provided; (2) A network of

circuit elements: resistances, reactances, semiconductors

etc. to perform a specific function.

The vertical space reserved along the side of a pole or

tower to permit ready access for linemen to equipment and

conductors located thereon.

Anything such as a wire or cable which is suitable for the

carrying of an electric current.

(1) Transmitting and/or receiving of information signals, or

messages between two or more points; (2) the information

thus received.


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FLAME RETARDING

FLASHOVER

FUSE

GROUND

GROUND BUS

GROUND RING

GUY

GUY, OVERHEAD

GUY, ANCHOR

GUY EXPOSED

Property of materials or structures such that they will not

convey flame or continue to burn for longer times than

specified in the appropriate flame test.

A discharge through air, around or over the surface of solid,

liquid or other insulation, between parts of differentpotential of polarity, produced by the application of voltage

such that the breakdown path becomes sufficiently ionized

to maintain an electric arc.

A device used for protection against excessive currents.

Consisting of a short length of fusible metal strip which

melts when the current through it exceeds the rated amount

for a definite time.

A conducting connection, whether intentional or accidental,

by which an electric circuit or equipment is connected to

the earth, or to some conducting body of relatively large

extent that serves in place of the earth.

A bus to which the grounds from individual pieces of

equipment are connected, and that, in turn, is connected to

ground at one or more points.

A configuration of grounding conductors arranged around a

structure such as building, tower footing, tower guy, anchor

etc. normally connected to an earth ground at one or morepoints.

A tension member (of solid or stranded wires) used to

withstand an otherwise unbalance force on a pole or other

overhead lines structures.

A guy extending from a pole or structure to a pole structure

or tree and is sometimes called a span guy.

A guy which has its lower anchorage in the earth.

A guy which has any part less than 2.5 meters from the

vertical plane of any electric power conductor of more than

250 volts.


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MAINTENANCE

MANHOLE

MANUAL

MESSENGER

NOISE

OPERATING CONTROL

PLANT

PLANT, INSIDE

PLANT, OUTSIDE

PRACTICABLE

PROTECTOR

PROTECTOR, CARBON

BLOCK

All of the work required to keep the plant, circuits, lines,

facilities, systems and services up to standards. This

includes testing, trouble clearing, repairing, and replacing

defective elements.

A subsurface chamber, large enough for a person to enter,in the route of one or more conduit runs, and affording

facilities for placing and maintaining in the runs,

conductors, cables, and any associated apparatus.

Operated by mechanical force, applied directly by personal

intervention.

Stranded steel wires in a group which generally is not a part

of the conducting system, its primary function being to

support wires or cables of the system.

Any unwanted disturbance in a communication system

which tends to obscure the clarity and validity of a signal in

relation to its intended end use.

A control, usually a knob, pushbutton or lever, provided to

enable the user to cause the appliance to perform its

intended function, without the use of tools, when the

appliance is in normal operating condition.

A general term applied to the whole or portion of thephysical property of a communication company which

contributes to the furnishing of communication service.

All plant which is inside of building.

All plant which is out of doors not in building, such as

poles, conduits cables, etc. installed overhead or

underground.

Capable of being accomplished by reasonably available and

economic means.

A device which provides protection from over-voltage

and/or over-current.

A protector whose voltage limiting element utilizes carbon

blocks.


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PROTECTOR, GAS TUBE

QUALIFIED

RADIANT ENERGY

RADIATE

ROD, GROUND

ROD, LIGHTNING

RECONSTRUCTION

SERVICE DROP

SAG

SPAN

SUPPLY CIRCUIT

SYSTEM, ELECTRONIC

TELECOMMUNICATION

A protector whose voltage limiting element employs

electrodes in a gas filled (neon, argon, etc.) envelope.

Persons trained and authorized for the construction,

maintenance and operation of the apparatus, circuit or

system and responsible for the safety precautions involved.

Any energy which radiates in the form of radio waves,

infrared (heat) waves, light waves, X-rays, etc.

The spreading out of radiant energy.

A metallic rod, driven into the ground to provide an

electrical connection to the earth.

A metallic rod carried above the highest point of a pole or

structure and connected to earth by a heavy copper

conductor intended to carry lightning currents directly to

earth.

That work which in any way changes the identity of the

plant or stations or portions thereof.

The installation from the terminal on the pole to the

protector at the customer premises.

The maximum departure, measured vertically, of a wire orcable in a given span from a straight line between the two

points of support of the span at 60 C and no wind loading.

The horizontal distance between two adjacent supporting

points of a cable or wire.

The branch circuit supplying electrical energy to the

equipment or appliance.

A configuration or arrangement of one or more electronic

equipment producing the desired performance.

Any transmission, emission or reception of signs, signals,

writings, images, sounds or intelligence of any nature by

wire, radio, visual, or other system that may in the future

become known or developed.


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TENSILE STRENGTH

TENSION

TENSION, MAXIMUM

ALLOWABLE

TENSION, MAXIMUM

WORKING

TOWER DISPLACEMENT

TOWER SWAY

TOWER TWIST

UNDERGROUND

WORKING SPACE

The pulling stress required to break a material, such as a

wire, express in kilograms of stress per cross-sectional area.

Mechanical stress caused by forces which tends to stretch

or severe the material stressed.

One half of the tensile strength for the messengers guys,

etc. and one fourth of the tensile strength for

communication cables and wire.

The tension resulting under theconstruction arrangement

with the maximum loading conditions specified in section

4.

The horizontal displacement of a point on the tower axis

from its no-wind load position at that elevation.

Tower sway at any specified elevation shall be defined as

the angular displacement of a tangent to the tower axis at

the elevation from its no-wind load position at that

elevation.

Tower twist at any specified elevation shall be defined as

the horizontal angular displacement of the tower from its

no-wind position at that elevation.

Describing communication facilities installed below thesurface of the earth.

The space extending laterally from the climbing space,

reserved for working below, above between conductor

levels; the space surrounding a device or equipment.


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III. GENERAL ELECTRICAL PROTECTION AND

GROUNDING REQUIREMENTS

3.1 GENERAL

3.1.1 Objective

3.1.2 Lightning

3.1.3 Power Contact / Induction

3.1.4 Acoustic Shock

3.1.5 Electric Shock

3.2 PROTECTION METHODS

3.2.1 Shielding

3.2.2 Voltage Limiting

3.2.3 Current Limiting and Interrupting

3.2.4 Grounding

A. Purpose

B. Ground Resistance

C. Made Ground

3.3 METHODS AND MATERIALS

3.3.1 Lightning Rods

3.3.2 Fuses

3.3.3 Surge Arrester

3.3.4 Grounding and Bonding

3.4 MEASUREMENTS

3.4.1 Ground Resistance Test Methods

3.4.2 Earth Resistivity

3.4.3 Determining Good Electrode Location

3.4.4 How to Improve Grounds

3.5 MAINTENANCE AND INSPECTION


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SECTION III

GENERAL ELECTRICAL PROTECTION AND

GROUNDING REQUIREMENTS

3.1 GENERAL

Electrical protection measures covered in this Code are directed against the effects of lightning,

accidental contact with power lines, voltages/electromagnetically/electrostatically induced into

communication circuits by normal or fault currents in parallel runs of power lines and, also, local earth

potential rises due to the flow of lightning or power fault currents.

3.1.1 Objective

Communication systems are subject to electrical hazards from exposure to lightning and power

systems and unless adequate protection measures are employed, such exposures may result in loss of life,

service interruptions and excessive maintenance expense.

A. The primary considerations of electrical protection are:

a) to minimize, as far as practicable, electrical hazards to persons engaged in construction,

operation, maintenance or use of communication systems;

b)

to reduce, as far as practicable damage to equipment and plant;

c)

to eliminate, as far as practicable, any fire hazard resulting from the operation of

communication systems; and,

d) to minimize, as far as practicable, acoustic shock hazards to anyone using communication

services.

B. The amount of protection to be adopted and employed is determined by a proper balance

between:

a) the cost of protection measures employed plus the amount required to maintain the

protection level and adopted; and,

b) the value of damage to or loss of life and property and/or that of service interruptions

caused by electrical hazards.

C.Protection measures may be more costly or impractical to add on or to an operating plant, so, it is

desirable to consider protection requirements in the initial setting-up of the plant.

D.The standards specified in the Code evolves around optimum protection, explain in 3.1.1.B, but

sometimes the state of the art progresses and new techniques evolve that meet the intent of the Code


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much more effectively that its own specific requirements, and in such cases, additional protection may

be use provided no provision in this code is violated.

E. When the safeguarding od human life is involved, even if not actually required by this Code,

communication entities should update its practice voluntarily and as soon as possible rather than wait

for the revision.

3.1.2Lightning

Lightning is an electrical discharge which occurs between clouds and also from cloud to earth. It is

latter type of discharge that is of concern in this Code.

A.

Lightning surges can appear in various parts of a communication system and produce explosive

effects, dielectric failure and fusing of conductors.

B. The path lightning takes depends upon the impedance presented to its wave front. With a wave

that rises from zero to crest value in from 1 and to 10 micro-seconds, the wave front appears to be a

signal whose frequency is from 25 to 250 KHZ.

C. Lightning behaves very much like radio frequency voltages and as much as such its behavior

can be predicted fairly accurately and protection measures can be selected, considering this

characteristic.

D.

Lightning surges may reach indoor equipment and circuits thru exposed portions of the

communication system such as antenna towers, transmission lines, telephone cables, etc. Lightning may

reach buried plants by a direct stroke on portions of the plant exposed above ground and by arcing to

the plant from ground thru plant, trees, man-made structures or the ground itself.

3.1.3. Power Contact/I nduction

The necessity for constructing power and communications facilities near each other and the

advantages to both interest of joint occupancy of poles and support structures present power

contact/induction problems that must be carefully considered.

A. Good construction and adequate spacing between power and communication facilities are the

first line of defense against power contact and power induction hazards. This essentially keeps foreign

potential out of the communication plant.

B. The second measure is to provide paths to ground on the communication facilities sufficient to

prevent excessive voltage rise in the communication plant and utilization of current limiting devices.

C. Insulation on communication conductors may in many instances withstand secondary power

potentials but dependence on insulation alone introduces a considerable hazed.

D. Where the possibility of a power line contact is eminent, equipment connected to such lines shall

be provided with protectors capable of discharging sufficient current to fuse the line conductor, or they

shall be provided with lines fuses and surge arresters. Such protectors shall be adequately grounded to

prevent excessive rise in potential at the equipment locations.


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E. Communication control circuits to electric power stations are always required to function more

so during periods when there are faults on the power systems, so adequate protection is required.

F. A disturbance affecting communication circuits serving electric power stations is ground

potential rise at the power stations. This potential is developed between the power station ground and

the remote ground during periods when large ground currents, such as phase to ground fault currents are

flowing in the station ground. The magnitude of this potential is the product of the ground current and

the ground impedance.

G. Isolating transformers and/or neutralizing transformers and or other appropriate devices should

be utilized to prevent disturbance in communication circuits exposed to a rise in ground potential.

3.1.4Acoustic Shock

Acoustic shock results from an abnormally high sound level, the physical effects of which may vary

from minor discomfort to serious injury.

A. Voltage surges on the communication plant initiated by foreign potential, principally lightning,constitute the major hazard, although switching transients may also be the cause.

B. To reduce the effect of acoustic shocks, a device consisting of two rectifiers, or other semi-

conductor elements in parallel with opposite polarities, shall be connected across the telephone receiver

or headset.

C.The device shall meet the following:

a) It should occupy a small space, so that it can be placed, for example, in the case of the

telephone receiver capsule.

b) Its electrical characteristics should not show significant changes under the temperature andhumidity conditions to which it is subjected in service.

c) It should not degrade the performance of the circuit it is connected to.

d) It should operate such that the amplitude of the sound pressure caused by the diaphragm of

the telephone receiver does not exceed 120 dB above 2 10 -4microbar at 1000 Hz.

3.1.5 Electri c shock

Current through the body rather than voltage of the circuit determines electric shock intensity. Voltage is

significantly only in so far as it is one of the factors determining the magnitude current.

A. Shock current is also dependent on the impedance of the circuit contacted plus the body

impedance of the victim.

B. Studies have shown that the average resistance of a dry adult human body is approximately

1,000,000 ohms. Wet or damage skin reduces this figure and 1,500 ohms is a conservative figure

representing the body resistance for safety calculations.


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C. Ventricular fibrillation is likely to occur when a 60 Hz rms. Current of 0.030 amperes and

above passes through ones chest cavity. Because of this, ANY CIRCUIT FROM WHICH IN

EXCESS OF 30 MA RMS AC OR 90 MA DC CAN BE DRAWN THROUGH A 1500 OHM

RESISTOR (45V RMS AC OR 135VDC) SHALL BE CLASSIFIED AS HAZARDOUS.

D. THE POTENTIAL DIFFERENCE AT ANY TIME BETWEEN ANY EXPOSED

STRUCTURE (EQUIPMENT CABINETS, HOUSINGS, SUPPORTS, ETC.) TO GROUND

(FLOOR, EARTH, ETC.) OR BETWEEN ANY EXPOSED STRUCTURE WITHIN THE REACH

OF AN ADULT PERSON (AOOROX. 1.5 METERS) SHALL BE NO GREATER THAN 45

VOLTS RMS AC OR 135 VOLTS DC.

E. THE POTENTIAL DIFFERENCE AT ANY TIME BETWEEN TWO POINTS ON THE

FLOOR OR EARTH SURFACE SEPERATED BY A DISTANCE OF ONE PACE, OR ABOUT

ONE METER, IN THE DIRECTION OF MAXIMUM POTENTIAL GRADIENT SHALL BE NO

FREATER THA 45 VOLTS RMS AC OR 135 VOLTS DC.

F. The limits specified in 3.1.5 D, and 3.1.5 E concern only the safety of personnel and should not

proper equipment performance.

3.2 PROTECTION METHODS

Rarely will it be economically feasible to meet protection requirements for all situations by means of

basic insulation incorporated in the design of equipment and plant. Additional protection measures are

usually required and may use one or combination of the following basic protection measures.

3.2.1 Shielding

Shielding is the provision of a grounded electrical conducting material located such that foreign potential

will be intercepted and surge currents diverted to ground with the least damage to plant equipmentpossible. Parallel or conductivity is essentially similar to shielding since a parallel conducting path is

provided to absorb surge current which otherwise can flow and cause damage to communication

plant/equipment.

3.2.2 Voltage L imiti ng

Voltage limiting prevents development of hazardous potential difference in communication plant by

direct bonding, when permissible or by use of surge current, discharges gaps, diodes, etc. which operate

under abnormal voltage condition.

3.2.3 Current Limiti ng and Interr upting

Current in a circuit can be kept from rising above a predetermined value by the use of a fuse in series

with the circuit. When current flows through a fuse for a specified time with a magnitude greater that its

rating, the fuse will interrupt the current.


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B. The material for the lightning rod shall be of galvanized iron/steel, copper weld or other

corrosion-resistant material. The material selected shall be resistant to any corrosive condition existing

at the installation or shall be suitably protected against corrosion.

C. Lightning rods shall be mounted atop structures not less than 30 cm. above the highest point of

the structure or not less than 30 cm. above the point which creates an effective electrical height for the

structure and to encompass all other elements, mounted and protruding horizontally from the structure,

within the area explained in 3.3.1 A.

D. A No. 2 AWG grounding conductor connected to the lightning rod shall be run in the shortest

route directly to the master ground bus or direct to earth without intervening splices or connection, free

from sharp bends. Each lightning rod shall require a separate of # 2 AWG grounding conductor.

E.Structures not requiring lightning rod installations are:

a) Structures within the area described in 3.3.1.A. due to nearby taller buildings or structures.

b)Passive reflectors and other similar fully metallic structures. Provided that its footing or aconnection to a separate made ground provides sufficient grounding for the structure and that

provision 3.1.5 D. is not violated.

c) Metallic antenna towers or poles where the antennas and their supports mounted on the

metallic tower or pole have electrical continuity all the way from all elements to the structure and

its footings and where a connection to a separate made ground provides sufficient grounding for

the structures and provided further that provision 3.1.5. D. is not violated.

F. All other structures not covered by provision 3.3.1.E. shall be provided with lightning rod or

rods as required considering provision 3.3.1.C.

G.The grounding system of lightning rods shall not be used as grounding conductors for any part

of a plant.

3.3.2 Fuses and Current Interrupting

Current interrupting may be accomplished by employing one or any combination of the following:

a)Fuse Link (fuses)

b)Heat coils

c)Fuse cable

d)Automatic circuit breaker

A.Fuses are effective only when its time and current operating characteristics are matched to that

of the circuit it is intended to protect.

B. After the fuse has opened, an arc may persist under the influence of excessive voltage. Failure

of the arc to clear rapidly constitutes hazard and defeats the purpose of the fuse.


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C. Fuses are not effective for limiting short duration surges so it becomes necessary to provide

some means of diverting surge currents through other paths having adequate current carrying

capacity.

D. Heat coils that guard against sneak current fire hazard and will carry 0.35 ampere for about

three hours and will operate within 210 seconds and 0.54 ampere.

E. Fuse cables are telephone cable sections installed in series and prior to the plant being

protected and are one size smaller than the section to which they are connected.

F. An automatic circuit breaker is a device which opens the circuit when the current exceeds a

predetermined rating a specified time without causing injury to itself and capable of being reset when

a default condition no longer exist.

G. The choice of current interrupting device or method shall consider the cost of the protection

measure/s against the value of service continuity and cost of system damage but personnel safety shall

never be jeopardized.

3.3.3 Surge Ar resters

Surge Arresters are normally open circuited devices and pass no significant current at normal

operating potentials and shall meet the following fundamental requirements:

A.Striking voltage must be as constant as possible even after several successive discharge.

B. The transition from glow to arc discharge must occur at less than one ampere. Are discharge,

once established, must be very stable, and spontaneous transition from an arc to glow discharge must

never occur.

C.The arcing voltage must be as small as possible.

D.It must be capable of carrying several tens of amperes for periods of the order of one second. It

must be able to repeat such operation several times at very short intervals without its characteristics

being affected.

E.If the above are exceeded, the surge arrester must fail safe, this shall be achieved through

final short-circuiting of the electrodes. The surge arrester must never be destroyed by shattering of the

enveloped in such a way as to leave the electrodes exposed, or by breakage of an internal connection,

since in such cases the circuit is no longer protected and no warning of the fact is given.

F.The choice of breakdown voltage rating of surge arrester shall be as low as may possible beallowed by the facility to which it is to be connected.


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A.The direct method is the simplest way to make an earth resistance test. With this method, resistance

of two electrodes in series is measured theelectrode under test and the reference ground or water system.

There are three important considerations with this test method:

1) The reference ground or water systems must be extensive enough to have negligible

resistance.

2) The water pipe must be metallic throughout without any insulating couplings or flanges.

3)

The earth electrode under test must be far enough away from the water-pipe system to be

outside its sphere of influence.

Fig. 3-1Connections for a direct or two terminal ground resistance test.


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B. The Fall of Potential method uses two reference rods. Placing of the two reference rods is critical

and the instruction of the instrument manufacturer must be followed.

Fig. 3-2 Connections for a Fall of Potenti al or Three Terminal Ground Resistance Test.

Fig. 3-3Fall of potenti al method of testing.

C. Other methods for ground resistance measurements may be used such as Voltmeter-ammeter

Method and Triangular method, provide the limitations of each method are considered and due safeguards

taken.


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B. In soil, conduction of current is largely electrolytic so the amount of moisture and salt content of

the soil radically affects its resistivity. Amount of water in the soil varies with the weather, time of the

year, nature of sub-soil and depth of the permanent water table.

-

Moisture Content Resistivity, Ohm-Cm.

% by weight Top Soil Sandy Loam

0 1000 106 1000 106

2.5 250,000 150,000

5 165,000 43,000

10 53,000 18,500

15 19,000 10,500

20 12,000 6,300

30 6,400 4,200

From: An Investigation of Earthing Resistance by P.J. Higgs I.E.E.E.

Jour., vol. 68, p. 736, Feb. 1930.

Pure water has a high resistivity; naturally-occurring salts in the earth, dissolve in water, lower its

resistivity.

-

Added Salt % by Weight

of Moistur e Resistivity, Ohm-Cm.

0 10,700

0.1 1,800

1.0 460

5 190

10 130

20 100


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C. An increase in temperature will decrease resistivity because water in soil mostly determines the

resistivity and an increase in temperature decreases the relativity of water. This is shown in the following

table.

- EFFECT OF TEMPERATURE ON EARTH RESISTIVITY

Temperature Resistivity, Ohm-Cm.

C F

20 68 7,200

10 50 9,900

0 32 (water) 13,800

0 32 (ice) 30,000

-5 23 79,000

-15 14 330,000

D. Earth resistivity is a very variable quantity and to determine the value at a given location at a

given time, the only sure way is to measure it.

E.The deeper ground electrode gives a more stable and lower value of resistance. Electrodes must

reach deep enough level to provide permanent moisture content and stable temperature.

Determin ing Good Electrode Location

3.4.3A good low-resistance ground electrode depends upon a low-resistivity soil in a location where the

electrodes can be driven. There are two approaches to picking this location:

a) Drive rods in various locations to such depths as may be required and measure the resistances

while the rods are being driven.

b)Measure the earth resistivity before driving ground rods then calculate the number and length of

rods required.


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How to improve grounds

3.4.4When the ground-electrode resistance is not low enough, undertake the following:

A. Lengthen the ground-electrode in the earth

Fig. 3-4 Ear th resistance decreases with depth of electrode in earth .

B. Use multiple Rods.

Fig. 3-5Comparati ve resistance of mult ipl e rod earth electrodes.

Single rod equal 100%


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Fig. 3-6 Ef fect of vari ation i n earth r esistivity wi th depth on the resistance

of a hor izontal ground 150 meters long and 0.4 cm, diameter bur ied

at the sur face.

Fig. 3-7 Vari ation of resistance of vertical ground rod with length for

vari ous diameters as indicated on curves, for an earth r esistivity

of 100 meter-ohms.


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Fig. 3-8 Vari ation of r esistance of hor izontal ground with length ground

at the sur face and at a depth of 30 cm, for an earth resistivi ty of

100 meter-ohms and for a wir e diameter of 0.2E cm (# 10 wire).

Fig. 3-9Var iati on in combine resistance of rods connected in mul tiple when arrange on a straight l ine

or a circle with spacing between rods equal to length of rods. Dashed line indicates combined

resistance without mutual effects. Rod length 240 times rod radius as for 5 ft . rods of inches

diameter.


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IV. GENERAL STRENGTH REQUIREMENTS

4.1 GENERAL

4.2 LOADING ZONES

4.2.1 Heavy Loading Zone

4.2.2 Medium Loading Zone

4.2.3 Light Loading Zone

4.3 SAFETY FACTORS

4.4 TRANSVERSE STRENGTH

4.5 VERTICAL STRENGTH

4.6 LONGITTUDINAL STRENGTH REQUIREMENTS

4.6.1 Reduction in Stress

4.6.2 Use of Guys and Braces

4.6.3 Unbalance Loads

4.7 ULTIMATE STRENGTH OF MATERIALS

4.7.1 Wood

4.7.2 Structural Steel4.7.3 Reinforce Concrete

4.7.4 Conductors, Span Wires, Guys, Messengers

4.7.5 Tower or Pole Foundations and Footings

4.8 DETAILED STRENGTH REQUIREMENTS

4.8.1 Poles, Towers and Other Structures

4.8.2 Crossarms

4.8.3 Pins and Conductors

4.8.4 Conductors4.8.5 Insulators

4.8.6 Guys and Anchors

4.8.7 Messenger and Span Wires

4.8.8 Hardware.


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SECTION IV

GENERAL STRENGTH REQUIREMENTS

4.1 GENERAL

The Section established provisions covering mechanical strength requirements used in conjunction

with electronic equipment or systems either alone or when involved with electrical power systems. The

provisions of this Section are supplemented in many instances by provisions in other sections.

The rules in this Code complement applicable provisions in the Building Code of the Philippines and

the Philippine Electrical Code. The more restrictive or stringent rules shall prevail.

4.2 LOADING ZONE

The following conditions of the temperature and loading shall be used for the purpose of this Code in

determining the strength required by poles, towers, structures, and all parts thereof as well as in

determining the strength and clearances of conductors. More stringent conditions may be used if desired.

4.2.1. Heavy Loading Zone

A. Heavy loading shall apply to those parts of the Republic of the Philippines as shown in Fig. 4-1.

This loading shall be taken as the resultant stress due to wind and dead weight for 240 kilometer per

hour (kph) wind velocity.

a)Wind pressure on protect area on cylindrical surfaces shall be computed as being 60% of that

for flat surface.

Where lattice structures are used, the actual exposed area of one lateral face shall be increased

by 50% to allow for pressure on the opposite face, provided by this computation does not indicate agreater pressure than would occur on a solid structure of the same outside dimensions, under which

conditions, the latter shall be taken.

b)Temperature shall be considered to be 27C at the time of maximum loading. The maximum

temperature shall be assumed as 65C in computing sag under this condition.

B. Medium loading shall apply to those parts of the Republic of the Philippines as shown in

Fig. 4-1. This loading shall be takes as the resultant stress due to wind for 200 KMP wind velocity and

dead weight under the following conditions:

a)Wind pressure on project area on cylindrical surface shall be computed as being 60% of thatfor flat surface.

When latticed structures are used, the actual exposed area of one lateral surface shall be

increased 50% to allow for pressure


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Fig. 4-1Wind Loading Map


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on the opposite face, provided this computation does not indicate a greater pressure than would

occur on a solid structure of the same outside dimensions, under which conditions, the latter shall

be taken.

b) Temperature shall be considered to be 27C at the time of maximum loading. The maximum


C. Light loading shall apply to those parts of the Republic of the Philippines as shown in Fig. 4-1.

This loading shall be taken as the resultant stress due to wind for 160 KHP wind velocity and dead

weight under the following conditions:

a) Wind pressure on protected area on cylindrical surface shall be computed as being 60% of

that for flat surface.

When latticed structures are used, the actual exposed area of one lateral surface shall be

increased 50% to allow for pressure on the opposite face, provided this computation does not

indicate a greater pressure than would occur on a solid structure of the same outside dimensions,

under which condition, the latter shall be taken.

b) Temperature shall be considered to be 27C at the time of maximum loading. The maximum


4.3 SAFETY FACTORS

4.3.1 The safety factors specified in these rules are the maximum allowable ratios of ultimate strengths of

materials to the maximum working stress, except that:

A. The safety factors for structural steel (towers, poles, cross-arms, supports) shall be applied as

specified in Rule 4.7.2 and

B. The safety factors for wood members in bending shall be applied to longitudinal tension and

compression as ratios of the module of rupture to the maximum working stress. The maximum working

stresses used with these safety factors shall be the maximum stresses which would be developed in the

materials under the construction arrangement with temperature and loadings as specified in Rule 4.2.

4.3.2 Lines and elements of lines, upon installation or reconstruction shall provide, as a minimum, the

safety factors specified in Table 4-1 for vertical loads and load transverse to lines and for loads

longitudinal to lines except where longitudinal loads as balanced.


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4.4.1 Special Pr ovisions

Where it is impossible to obtain the required transverse strength except by the use of side guys or

special structures and it is physically impossible to install them at the location of the transversely weak

support, the strength may be supplied by side guying the line at each side of, and as near as practicable to,

such weak support with a distance not in excess of 245 m. between the supports guyed; provided that the

section of the line between the transversely weak structures is weak in regard, to transverse loads only,

that it is in a straight line and that the strength of the side guyed supports is calculated on the transverse

loading of the entire section of line between them.

4.5 VERTICAL STRENGTH REQUIREMENTS

In computing vertical strength requirements, the loads upon poles, towers, foundations, cross-arms,

pins, insulators, and conductor fastenings shall be their own weight plus the superimposed weight which

they support, including that of wires and cables under the loading conditions of Rule 4.2 plus that which

may be added by difference in elevation of supports. The resultant of vertical and transverse loadings on

conductor shall be used in determining the allowable and working tensions or sags in accordance with

Rule 4.2. In addition, a vertical load of 90 kg. at the outer pin shall be included in computing the vertical

loads on all cross-arms. All members of structures shall be constructed to withstand vertical loads as

specified above the safety factors at least equal to those specified in Rule 4.3.2.

4.6 LONGITUDINAL STRENGTH REQUIREMENTS

In computing the longitudinal strength requirements of structures, or any parts thereof, the pull of the

conductors shall be considered as that due to the maximum working tension in them under the loading

conditions specified in Rule 4.2.

4.6.1 Reduction in Stress

Stresses in supporting structures due to longitudinal load may be reduced by increasing the conductor

sags, provided that prescribed conductor clearances in Section VII are maintained.

4.6.2 Use of Guys and Br aces

The longitudinal strength requirements for poles, towers, and other supporting structures shall be met

either by the structure alone with the aid guys or braces. Deflection shall be limited by guys or braces

where such structures alone, although providing the strength and safety factors required, would deflect

sufficiently under the prescribed loadings to reduce clearances below the required values.

4.6.3 Unbalance Loads

Poles, towers, or structures with longitudinal loads not normally balanced (as the dead ends or angles

greater that can be treated as in Rule 4.4) shall be sufficient strength or shall be guyed or braced, to

withstand the total unbalanced load with the safety factors at least equal to those specified in Rule 4.3.


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Tension and Bending: The yield point, 23.2 Kg/mm2shall be divided by the safety factor to determine

the maximum allowable working stress.

Compression: The Maximum allowable working stress shall be calculated by the following formula:

Where Smax= maximum allowable working stress in Kg/mm2

fs = safety factor specified in Rule 4.3

YP = Yield point of the steel. 23.2 Kg/mm2

1 = unsupported length of a member

r = radius of gyration of a member.

Shear: The ultimate tensile strength, 3.876 Kg/cm2 shall be multiplied by 2/3 and divided by the

safety factors specified in Rule 4.3 to determine the maximum allowable working stress.

Where the figures given are used, structural steel shall conform to ASTM A7-39 for carbon steel of

structural quality. Other values may be used for steel of other strength provided the yield point and

ultimate tensile are determined by test.

4.7.3 Reinforced Concrete

Values used for ultimate strengths of reinforced concrete in conjunction with safety factors given in

Rule 4.3 shall not exceed the following:

Reinforcing steel, tensile or compression strength in Kg/cm23867

Concrete, 1:2:3 Age Compression Strength

7 days 63.5 Kg/cm2

30 days 169.00 Kg/cm2

90 days 218.00 Kg/cm2

6 months 310.00 Kg/cm2

If reinforced concrete is designed for higher strength values which are proven by test, such values may be

used in lieu of the figure given.

4.7.4 Conductors, Span Wires, Guys, Messengers

Values used for ultimate strength of wires and cables shall not exceed those given in Tables 10 to 14

in the Appendix. For use of types of wires and cables of other materials or composition not included in

the Appendix, values for ultimate strength similarly derived from specifications of the ASTM shall be

used except that, if such specifications are non-existent, manufacturers specifications may be used

provided that test have been made which shall justify the manufacturers rating for ultimate strength.


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4.7.5Tower or pole foundations and footings

In calculating the resistance of foundations or footings of towers, poles and pole line structures to

uplifts, the weight of concrete shall be taken as not more than 2322.6 Kg/mm3 the weight of earth

(calculated 30 degrees from the vertical) shall be taken as not more than 1441.6 Kg/mm 3. The resistance

of soil to the depression of foundations shall be calculated from the best available data on the soil in

question. In lieu of calculation, the strength of foundations or footings against uplift or depression may be

determined by test under the soil conditions obtaining.

4.8 DETAILED STRENGTH REQUIREMENTS

4.8.1 Poles, Towers and Other Structures

A. Strength

Wood poles shall be sound timber, free from defects which would materially reduce their strength

or durability and they shall have sufficient strength to withstand, with safety factors not less than those

specified in Rule 4.3, the maximum stresses to which they are subjected under the loading conditionsspecified in Rule 4.2. The modulus of rupture used in calculation and safety factors shall be not greater

than the value given in Rule 4.7.1.

Steel and reinforce concrete poles, together with their foundations, shall be such material and

dimensions as to withstand, with safety factors not less than those specified in Rule 4.3, the maximum

stress to which they are subjected under the loading conditions specified in Rule 4.2. The fiber stress

values used in calculation of safety factors shall be specified in Rules 4.7.2 and 4.7.3.

Certain poles are subject to special stress due to angles in the line, dead ending of conductors, or

other attachments, which stresses must be included in computing the loading and safety factor. Poles

subject to these special stresses sometimes require the use of guys, in which case the pole below thepoint of guy attachment shall be considered merely as a strut, the guy taking all lateral stresses. In such

cases, the pole strength requirements shall apply at the point of guy attachment rather than at the ground

line. Spliced or stub reinforced poles or pole top extensions, including the attachments (joints) of

different members involved, shall meet all of the vertical, transverse and longitudinal strength

requirements of these rules as if a whole pole were used.

B.Setti ng of Wood Poles

The depth of pole setting given in Table 4-3 are applicable to wood poles set in firm soil or in solid rock.

Where the soil is not firm, deeper settings or special methods of pole shall be resorted to. Where unguyed

poles are set subject to heavy strain, or at corners or curves, a greater depth shall be used. Guyed poles

may be set more than 0.3 meter less than the depths specified in Table 4-3 provided the guys do not

assume any normal working load under condition of no wind and the resulting depths of setting are not

less than 1 meter.


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Table 4-3

Total Length Depth in Depth in

of Pole, Meter Soil , Meter Rock, Meter

6.0 1.2 1.0

7.5 1.4 1.0

9.0 1.5 1.0

10.5 1.5 1.0

12.0 1.7 1.0

13.5 1.8 1.2

15.0 2.0 1.2

17.0 2.0 1.4

18.0 2.0 1.4

20.0 2.3 1.5

21.0 2.3 1.5

23.0 2.5 1.724.5 2.5 1.8

C. Gains

Gains or equivalent means may be provided for increasing surface contact of cross-arms with sound

wood poles. Where gains are cut, the depth shall be not less than .5 mm. or more than 5 mm. Slab

gains, metal gains, pole bands, or assemblies of wood or metal supports that provide suitable surface

contact and adequate strength are permitted.

4.8.2 Cross-arms

A. Material

a. Wood shall be of suitable grades listed in Table -2 or other accepted species.

b. Metal shall be structural steel, cast steel, or malleable cast iron, properly galvanizedor

otherwise protected to resist corrosion, or may be of any corrosion-resisting metal or alloy.

B. Minimum Stress

a. Wood shall have a cross section not less than .5 .5cm except that cross-arm 2 meter

or less in length may be 7 9.5 cm.

b.Metal the physical properties as a result of dimensions, shape and cross-sectional area ofmetal cross-arms shall be such as to result in sufficient strength to meet the requirements of Rules

4.5, 4.6, 4.7.2 provided the thickness of any element shall be not less than 0.23 cm.


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C.Strength

Cross-arms shall be securely supported by bracing, where necessary to withstand unbalance vertical

loads and to prevent tipping of any arm sufficiently to decrease clearances below the values specified in

Section 7. Such bracing shall be securely attached to poles and cross-arms. Supports in lieu of cross-

arms shall have means of resisting rotation in a vertical plane about their attachment to poles or shall be

supported by braces as required for cross-arms. Metal braces or attachments shall meet the requirements

of Rule 4.7.2 and 4.8.8. In computing the strength requirements to meet vertical loads, the effect of such

bracing may be considered.

(1)Where longitudinal loads are normally balanced, cross-arms supporting conductors shall have

sufficient strength to withstand a load, applied in the direction of the conductors at the outer pin

position of 180 kg. with a safety factor of not less than unity.

(2)Where cross-arms are subjectedto unbalanced longitudinal loads they shall have sufficient

strength to meet the strength requirements with safety factors at least equal to those specified in

Rule 4.3. At unbalanced corners and dead ends, where conductors are supported on pins and

insulators, double cross-arms shall be used to permit conductor fastenings at two insulators and thus

retard slipping.

D. Replacements(See Rule 4.3.3).

4.8.3 Pins and Conductors Fastenings

A. Material

1. Pins Insulator pins shall be of galvanized iron or other corrosion-resisting metal or of other

suitable material

2. Fastenings Conductor fastenings shall be of galvanized steel, galvanized iron or other

corrosion-resisting metal.

B.Size

1. Wood Pins The minimum diameter of the shank shall not be less than 0mm.

2. Metal Pins The minimum diameter of the shank shall not be less than .5 mm.

3.Fastenings and Tie Wires Fastenings and tie wires shall have not sharp edges at points of

contact with conductors, and shall be applied in such a manner so as not to damage the conductor.

The materials and minimum sizes of tie wires for the various sizes and types of conductor shall beshown in Table 4-4. Flat wire having a cross-sectional area not less than that of round wire of the

gauge specified for tie wires may be used.


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Table 4-4

SIZE AND MATERIAL OF TIE WIRE

L ine Conductor Tie Wir e

Mater ials Size Size Mater ial s

Copper, bronze 6AWG Same as line Soft copper or

Copper-covered smaller conductor annealed copper-

steel or composites 4AWG 6AWG covered steel

of any of 2AWG or 4AWG

them larger

Galvanized iron or 10BWG and Sames as line Soft galvanized

galvanized steel smaller conductor iron or galvanized

9BWG 10BWG steel

8BWG 9BWG

4 & 6BWG 8BWG

Aluminum or 4AWG Same as line Soft aluminum

ACSR smaller conductor

2AWG or 4AWG do

larger

C.Strength

Insulator pins and conductor fastenings shall be able to withstand the loads which they may be

subjected to with safety factors at least equal to those specified in Rule 4.3.

1. Longitudinal loads normally balanced:

a) Insulator Pins Where longitudinal loads are normally balanced, insulator pins which

support conductors shall have sufficient strength to withstand, with a safety factor of not less

than unity, a load at the conductor position of 180 kg.

b)Conductorfastenings Where longitudinal loads are normally balanced, the tie wires or

other conductor fastenings shall be installed is such a manner that they will securely hold the

line conductor to the supporting insulators and will withstand without slipping of the conductor,

unbalanced pulls of 15% of the maximum working tensions but not more than 120 kg.

2. Longitudinal loads normally unbalanced At unbalanced corners and dead ends where the

conductor tensions are held by cantilever strength in pin-type insulators and pins, double pins and

insulators shall be used and each line conductor shall be tied or fastened to both insulators so as to

prevent slipping of the conductor under the maximum working tensions with a safety factor of 2

under the temperature and loading conditions specified in Rule 4.2.

D. Replacements(see Rule 4.3.3).


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4.8.4 Conductors

A. Material

Conductors shall be of copper, copper-covered steel, bronze, stranded cable composites of any of

the foregoing, aluminum, aluminum cable steel reinforced, galvanized iron, galvanized steel or of other

corrosion-resisting metal not subject to rapid deterioration.

B. Size

Size of conductors for various types of construction and service is specified in Selection 5 & 7.

C. Strength

1. Conductor shall have sufficient strength to withstand, with safety factors not less than those

specified in Rule 4.3, the maximum stresses to which they are subjected under the loading

conditions specified in Rule 4.2.

2.Sags and Tensions Conductor sags shall be such that in loading conditions specified inRule 4.2 the tension in the conductor shall not be more than one-half the breaking strength of the

conductor. The use of sags greater than the allowable minimum may be desirable in order to reduce

working tensions.

3.Splices Splices in conductors shall be in accordance with the requirements of Table 4-1

except as provided in Rule 4.7.4.

4. Service drops for telephone, data, etc. of No. 16 AWG paired copper wire maybe used,

provided they do not cross over power lines, trolly contact or feeder conductors of railways and the

like. Paired high strength service drops of No. 18 AWG high strength bronze or high strength

copper-covered steel may be used provided the breaking strength of the pair is not less than 155 Kg.

D.Replacements(see Rule 4.3.3).

4.8.5 I nsulators

A. Line

Insulators, supports, clamps, and other miscellaneous attachments shall be designed to

withstand, with at least the safety factors specified in Rule 4.3, the mechanical stress to which they

are subjected by conductors, wires or structures, under the loading conditions specified in Rule 4.2.

Pin insulators shall effectively engage the thread of the pin for at least two and one-half turns.

B. Guy

Guy insulators, including insulators in messengers, shall have mechanical strength at least equal

to that required of the guys in which they are installed.

C. Replacements(see Rule 4.3.3).


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4.8.6 Guys and Anchors

A. Material

The exposed surface of all guys and guy rods shall be of corrosion-resisting material.

B. Size

The size and strength of guys shall be not less than as specified in Table 4-5 and shall also be such

as to provided safety factors not less than those specified in Rule 4.3, for the loads imposed by the

construction under the loading conditions specified in Rule 4.2.

Table 4-5

MINIMUM SIZE AND STRENGTH OF GUYS

M inimum Size

Materi al of Strand Anchor, Guys Overhead Guys

1. Galvanized Steel 8 mm 6.5

Common or Siemens

Martin

High Strength or 6.5 m 5 m

Extra High Strength

2. Copper-covered Steel 3 No. 9AWG 3 No. 10AWG

3. Bronze 6.5 mm 3 No. 10AWG

Minimum Allowable 1454.54 Kg. 863.63 Kg.

Ultimate Strength (3200 lbs.) (1900 lbs.)

of Guys

C. Strength

When guys are used with poles or similar structures, capable of considerable deflection before

failure, they shall be able to support the entire load, the pole below the point of guy attachments acting

merely as a strut. Stranded wires shall be used when the ultimate strength of the guy exceeds 820 Kg.

Anchor rods and their appurtenances shall meet the same strength requirements as the guy wire or

strand (see Rule 4.3)


4.8.7 Messengers and Span Wires

A. Material

Messengers and span wires shall be stranded of galvanized steel, copper-covered steer or other

corrosion-resisting material not subject to rapid deterioration.


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B. Strength

Messengers and span wires shall be capable of withstanding, with safety factors as specified in Rule

4.3.; the tension developed because of the load they support combined with the loading conditions

specified in Rule 4.2. An allowance of 90 Kg. of vertical load for a man and cable chair shall be made

in computing tensions in messengers and span wires which supports cable except in the case of short

spans which are not required to support workman. The strength of guys supporting messenger loads

shall be such that the safety factor of such guys is not less than the safety factor required of the

messenger as specified in Rule 4.3. It is recommended that overhead guys shall be the same size as the

suspension strand to compensate for the angle between the plane of the horizontal load of the

suspension strand and the line of the guys.

C. Supports

Messenger supporting cables shall be attached to poles or cross-arms with hardware which provides

safety factors at least equal to those specified in Rule 4.3, based on the weight of the cable plus an

allowance of 90 kg. for the man and cable hair. All hardwares subject to injurious corrosion shall be

protected by galvanizing, or other suitable treatment.


4.8.8 Hardware

All pole line hardware shall be galvanized, otherwise protected by a corrosion-resisting treatment,

or shall be composed of material which is corrosion resistant.


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V. INDOOR PLANT SAFETY RULES

5.1 GENERAL RULES

5.2 RADIO TRANSMITTING & RECEIVING INSTALLATION

SAFETY REQUIREMENTS

5.2.1 Fixed Station Installation

5.2.2 Mobile Station Installation

5.3 SWITCHING EQUIPMENT INSTALLATION SAFETY

REQUIREMENTS

5.4 COMPUTER AND DATA INSTALLATION SAFETY

REQUIREMENTS

5.5 STATION INSTALLATION SAFETY REQUIREMENTS


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SECTION V

INDOOR PLANT SAFETY RULES

5.1 GENERAL RULE

This Section establishes safety rules for all electronics and communications equipment installed

and/or located inside buildings or in sheltered structures, except consumer products.

5.1.1 All electronics and communications equipment except consumer products installed and/or located

inside buildings or in sheltered structures shall be engineered, installed, operated and maintained in such a

manner that SHOCK CASUALTY or FIRE HAZARD shall not result when normally used and operated.

5.1.2 A grounding system shall form a part of all indoor electronics and communication installations

falling under any of the following category:

A. When any equipment is powered from 110 V. A.C. or higher;

B. When an outdoor exposed facility is connected to any equipment for its normal operation;

C. All radio stations, telephone/telegraph/telex exchanges and fixed computer installations.

5.1.3 The grounding system shall be designed to direct foreign potentials and surge currents in the

shortest route possible to earth.

5.1.4Potential rise on accessible parts shall be no greater than the values specified in rule 3.1.5 C.

5.1.5Strength consideration for indoor equipment installation shall be sufficient to assure that no casualty

hazard shall result from falling or collapsing equipment or their components.

5.1.6 Operation of electronic and communications equipment shall not result in emission of fumes,

chemicals, radiations, etc. to such a level considered hazardous by those recognized by the government to

make such assessment.

5.1.7 Users of electronics and communication system or services shall be protected from shock or fire

hazards attendant to the use of the service.

5.1.8 It shall be the users responsibility to ascertain that adequate internal protection is built into the

equipment by the supplier in such a manner that no shock or fire hazard shall result when the equipment

is operated within its rating.

5.1.9 The electrical protection measures shall coordinate with the inherent dielectric strength and surgecurrent carrying capacity of the equipment or system being protected.

5.1.10Only approved protectors and other electrical surge protection devices shall be used.


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5.1.11The amount of protection for the equipment to be designed into the system is dictated by the value

of service continuity and repair cost attributed to damages in the absence of the protection measure

against the cost of installing and maintaining the protection measures. Safeguarding of persons shall be

the foremost factor in the design and consideration of protection measures.

5.1.12Fuel tanks shall not be located between antenna towers and the radio building.

5.1.13 The building ground ring conductor shall be buried not less than 0.3 meters below grade level and

between 0.3 and 0.5 meters from the foundation. The building ground rods shall be spaced not more than

6.0 meters apart around the building.

5.1.14Where ground wires cross each other, they shall be bonded together to prevent arcing.

5.1.15Points with potential in excess of that specified in rule 3.1.5 as hazardous voltages may be made

accessible as may be required for testing/maintenance purposes by removal of shields or barriers so

marked indicating that its removal will expose hazardous voltage. The voltage of the part to be exposed

shall be indicated in the same marking with further instruction to return the shields or barriers after the

work.

5.1.16 When working on points specified in Rule 5.1.15, extreme caution shall be exercised and the

following observed:

A. Use tools with insulated handles;

B. Place rubber mats or equivalent on the floor where the persons required to access such points

may stand on;

C. Only authorized, competent persons shall be allowed to undertake work that may expose them

to such hazardous voltages.

D. No person shall undertake such work alone.

5.1.17Circuits and components capable of retaining an electrical charge after the power to the equipment

is turned off causing a discharge of 50 watt-seconds of energy or more through a 1500 ohms resistor

connected across its terminals, shall be fitted with circuitry to drain or remove this charge when the

equipment power is turned off.

5.1.18Stationary battery installation mounted on racks shall be fitted with earthquake bracings


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15 This grounding conductor run is form the main ground bar to the equipment rack lineup. This

conductor is normally made to run cable runways atop equipment rack lineup where individual

equipment rack and rack ground wires are bonded to.

16 For equipment racks, grounding conductors are fitted running the length of the rack to facilitate

neat individual equipment shelves grounding.

17 See No. 16

5.2 RADIO TRANSMITTING & RECEIVING SAFETY REQUIREMENTS

5.2.1 Fixed Station (Point-to-Point; Television, FM & AM, Radio; Space Communication)

This section covers radio transmitting and receiving stations at fixed locations used for point-to-point

overland or space communications and video, AM and FM transmission.

A. A fixed radio station building is not likely to be struck directly by lightning because of the

shielding effect provided by the antenna tower/s or support structures. However, waveguides, the

shield 2 of coaxial cables and high frequency antenna transmission lines can conduct hazardous

currents into the building unless adequate protective measures are employed. The station grounding

system is employed to divert as large a proportion of the surge current directly to earth before it enters

the building. The grounding system shall also be designed to reduce earth potential gradients in and

around the station building.

B.Radio site protection involves special consideration because direct lightning hits are usually

expected. The bonding, grounding and protection schemes shall have to be heavy duty and very

carefully engineered, installed and maintained in order to hold differences of potential between

various parts of the station to safety values. The installation shall be adequately grounded and

incoming overland communication and power lines fitted with special protection devices. The extentto which protection measures must be carried and their effectiveness is greatly affected by the earth

resistivity at the station location.

C. Equipment protection design is based on preventing voltage surges, beyond the voltage surge

limit of the equipment or parts thereof, from reaching that equipment or component. For solid state

component protection, low voltage protection devices have limited surge capability themselves,

several stages of protection may be employed.

D. Most electronic and communication equipment installations require A.C. power for certain

components. Commercial power lines, being susceptible to voltage and current surges due to

lightning and switching operations, shall necessitate protection considerations to prevent damage to

equipment connected to such lines.


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E. The earth electrode shall be any or a combination of made electrodes specified in rule 3.. C.

The ground resistance shall not be greater than 2.0 ohms at all times as measured by the fall of

potential method as specified in rule 3.4.1 B. Conductor size shall be no less than those specified in

Table 5-1. Aluminum, copper covered steel and other types of conductors may be used in place of the

copper conductor specified in Table 5-1 provided the current-carrying, corrosion-resisting

characteristics and insulation are equal to or better than the specification of the conductor beingreplaced. The minimum wire size specified in Table 5-1 is for electrical protection consideration only

if the system design calls for portions of the grounding system network to carry operating currents,

the conductor size shall be increased correspondingly.

5.2.2 Mobil e Station (Land mobile; Maritime mobile; Aeromobile)

This section covers radio transmitters, receiver, transceivers and allied equipment at mobile locations

such as:

1. radio installation on board vehicles, like automobiles, trucks, trains, etc. whose

movement or travel in confined overland.

2. radio installation on board water crafts like boats, ships, etc.

3.Aeromobile radio installations on board aircrafts and space crafts.

A. The counterpart base station of such mobile installations shall comply with safety provisions

provided under Rule 5.2.1

B. Installation of transceivers, handsets, control panels, microphones, loudspeakers, etc. shall not

increase the risk of injury of the driver or pilot and passengers in case of accident or collision.

C. Battery cables shall be fused as close to the battery terminals as practicable with fuse rating not

greater than 150% of the peak load current.

D. Battery cables shall have a current carrying capacity of not less than 250% of the peak load

current.

E. Battery cables shall have insulation strength rating of not less than 10 times the maximum

voltage to which it is to be connected and adequate mechanical strength to withstand the expected

abrasion; exposure to dirt, heat (150 C), humidity and the extreme environmental conditions mobile

installations encounter.

F. Battery or power wiring in aircraft installations shall be adequately fused in such manner that

current overloads due to equipment or wiring malfunction shall not affect other vital navigationequipment in the aircraft connected to the same battery or power supply.

G.Electronic and communication installations in larger water craft or trains are mostly powered

from normal A.C. supply and in such cases, rules in this Code to meet general rule 5.1.1 apply.

H.Cables to be used for watercraft installation shall be those approved for marine application.


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(Telephone, Telegraph, Telex etc.)

This section covers equipment installation employed for selective interconnection of channels of

communication using electro mechanical and/or electronic circuit elements to perform the function.

5.3.1Switching equipment is subject to damage from lightning and power fault currents which may be

conducted from outside plant cable or wire circuits. A.C. operated equipment can be damage from

lightning and switching surges conducted through the electric power lines. To protect personnel and

prevent damage to equipment these foreign potential surges shall be effectively limited by application of

suitable protective devices.

5.3.2 Surge arresters of suitable type and rating shall be connected on all wire circuits entering the

building except on wire lines meeting all of the following criteria:

1. The entire length is underground;

2. Not bunched with a circuit any portion of which is installed above ground level;

3. Not bridged to any wire circuit that may be exposed to foreign potential by contact or induction.

5.3.3 Depending on the desired protection level adopted, arresters should be fitted on power services

serving the station.

5.3.4The switching office earth electrode shall be any or a combination of made electrode specified in

Rule 3.2.4 C. The ground resistance shall be 5.0 ohms or less at all times as measured by the fall of

potential method.

5.3.5The earth electrode(s) provided under the rule 5.3.4 shall be bonded to the following (when present)

to form the switching office earth electrodes:

1. Continues buried metallic public water pipe system;

2. Continues buried metallic private water pipe system with at least 3.0 meters of buried pipe;

3. Deep well metal casing.

5.3.6 Connections to earth electrodes shall be made using methods and clamps acceptable to the entity

enforcing this CODE.

5.3.7For big offices, a ground bar shall be used, connected to the earth electrodes. The ground bar serves

as distribution or principal terminating point. For small offices the for ground may be omitted and

grounding conductor connected to the earth electrode on one end, free on the other end and running thefull length of the equipment line-up, where equipment rack/s shall be bonded.

5.3.8Ground conductor sizes, shall be in accordance with Table 5-1.

5.3.9 Insulation of all cables shall be polyvinyl-chloride (PVC) or equivalent formulation with equal or

better resistance to burning.


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5.3.10 Office furnitures required in the operations should be of metal construction or other non-

combustible material contents.

5.3.11 Stationary and other office and maintenance supply shall be stored in areas external to the

switching rooms. It shall be prohibited to store combustible materials in transformer vaults, switch gear

rooms and power distribution.

5.4 COMPUTER AND DATA SAFETY REQUIREMENTS

This section covers the minimum safety requirements in Electronic Data Processing Center

installations. Values, in terms of direct monitary cost, as a result of expensive components and in terms of

operational service continuity, tend to be extremely high and expensive damage to these installations can

have catastrophic consequences.

5.4.1The EDP equipment is AC operated and can be damaged by current surges conducted through the

electrical power line. To protect personnel and prevent damage to equipment, these foreign potential

surges shall be effectively limited by application of suitable protective devices.

The EDP Center earth electrodes shall be any or a combination of made electrodes specified in

rule 3.2.4 C and shall be engineered and installed in accordance with rules 5.3.4 through 5.3.8 of this

code.

5.4.2The Computer is the vital nerve center in any EDP installation and prevention of fire shall be the

overriding concern.

A. The computer shall be provided with physical separation or orientation to reduce or minimize

the effect of any detrimental external influences.

B. The facility shall be installed in a non-combustible housing structure. This shall include fire

and explosion-proof protection from the surroundings, such as firewalls, smoke detectors, water

proof ceilings, and floor covering materials of Vinyl tiles, high pressure plastic laminates, or other

non-combustible materials.

C. The large quantity of wiring associated with such installation and the mandatory requirements

for air-conditioning leads to concealed spaces either under the floor, in the walls, or in the ceiling.

Obviously, no combustible should be stored in these concealed spaces.

D. Power circuits and signal circuits shall be installed in separate conduits and raceways.\

E. The signal wiring shall be contained in cable structure with an over-all jacket or Polyvinyl

Chloride (PVC) or equivalent formulation with equal or better resistance to burning.

F. Office furnitures required in the EDP operations should be of metal construction or other

The Philippine Electronics Code Volume 1 (Safety)

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Transcript of The Philippine Electronics Code Volume 1 (Safety)