Bubble of Protection Complete System Protection ITW Linx A Division of Illinois Tool Works Inc.
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Transcript of Bubble of Protection Complete System Protection ITW Linx A Division of Illinois Tool Works Inc.
Bubble of ProtectionComplete System Protection
ITW LinxA Division of Illinois Tool Works Inc.
©2003
Overview Why Use Surge Protection?
Types of Surges
Technologies
Standards
The “Bubble of Protection”
Bonding and Grounding
Example
©2003
Why Use Surge Protection? Safety
Protect people from electric shock Protect equipment from damage Protect building wiring from excessive
electrical current
©2003
Why Use Surge Protection? Safety National Electric Code
National Fire Protection Association Telecom equipment under Article 800
Primary Protection at Building Entrance Secondary protection
©2003
Why Use Surge Protection? Safety National Electric Code Savings
Blown Equipment Service Calls Downtime Initial Investment with Net Savings
©2003
Why Use Surge Protection? Safety National Electric Code Savings Damaged Equipments
Equals….Headaches Lost Equipment Service Repairs System/Business Downtime Dissatisfied Customers Finger Pointing (Installer, Manufacturer, etc.)
©2003
Why Use Surge Protection? Safety National Electric Code Savings Damaged Equipments
Equals….Headaches Who’s Concerned?
Telephone and Power Companies Facility, Operations, and Telecom Managers Architects, Installers, Contractors,
Technicians Everyone!
©2003
Types of Surges Lightning
Most catastrophic of all surges Does not have to be a direct hit to cause
damage A lightning strike within a few miles can be
induced into aerial or buried cables 10,000,000 Volts 145,000 Amps (145kA)
©2003
Global Lightning Flashes 2000
©2003
Lightning in the U.S. 1989-1998
©2003
Types of Surges Lightning
Power Line Cross Excess current on the Communications line High Risk of Fire Injury to personnel Damage to equipment
©2003
Types of Surges Lightning
Power Line Crosses
Induction Current flow creates a magnetic field Two conductors run parallel and close to one another Field of one conductor can transfer energy to the other
conductor Example: Power is first restored following a blackout
Current
Field
©2003
Types of Surges Lightning
Power Line Crosses
Induction
Electrostatic Discharge Transfer of electrical energy from one material to
another Usually found in dry climates Produces high voltage with low current
Feel sensation at 4kv
Maximum Voltage = 30kV
Enough energy to damage integrated circuits (~35V)
©2003
Shock Thresholds
1mA Perception Threshold
3mA Mild Shock
8mASevere Shock (involuntary muscle movement)
10mA
Freezing Threshold (can’t let go)
35mA
Respiratory Paralysis
65mA
Heart Filtration (no blood flow)
©2003
Technologies Voltage Limiting
Gas Tube Discharge gap between two metal electrodes Poor control of peak voltage Clamping voltages are too high Discharge times are too slow Deposits build on the discharge plates with each
activating surge OK for electromagnetic switches, but not for today’s
electronics
©2003
Technologies Voltage Limiting
Gas Tube Solid State
Provides fast, precise, and long lasting protection Premium alternative to gas tube protectors Fast clamping at low voltages Performance can significantly reduce failure rates for both
protector units and surge sensitive equipment Improved reliability makes it ideal for critical service lines
©2003
Speed of a Surge
How Fast Does Electricity Travel Through A Wire? 186,000 Miles/Second
Number of Feet in a Mile? 5,280 Feet / Mile
Speed (in ft/sec) Electricity Travels Through a Wire 1,000,000,000 ft/sec
Time Required for Surge to Travel One Ft.0.0000000001 Sec.
(1 Nanosecond)
©2003
Speed of a Surge
Device Response TimeDistance Surge Traveled Past Device Before It Responded
Fuse 300,000 ns 300,000 ft
Carbon Block 5,000-10,000 ns5,000 - 10,000 ft
or 1-2 miles.
Gas Tube 4,000-5,000 ns4,000 - 5,000 ft
Or 1 mile.
Solid-State 2 - 5 ns 2 - 5 ft
©2003
Technologies Voltage Limiting
Gas Tube Solid State
Current Limiting Sneak Current Protector Fuses
Prevents the current that passes by the primary protector undetected from burning down building
©2003
Technologies Voltage Limiting
Gas Tube Solid State
Current Limiting Sneak Current Protector Fuses PTC’s
Positive Temperature Coefficient (PTC) Automatically reset once the over current is removed Service calls/costs are dramatically reduced Cost of replacement fuses eliminated
©2003
Standards National Electric Code (NEC)
National Fire Protection Agency for Safety Article 800 - Telecommunications All conductive paths entering or leaving a
building shall be protected by a listed primary protector as soon as possible, but no more than 50 feet past the building entrance
©2003
Standards National Electric Code (NEC) Underwriters Laboratory (UL)
Products listed Do not start on fire or cause a fire to be started, and Do not cause a physical safety hazard to the use
©2003
Standards National Electric Code (NEC) Underwriters Laboratory (UL)
UL497 - Primary Designed to protect against Lightning and Power Crosses
100 Amp, 10/1000
600V, 350A
Three Exceptions Large metropolitan area
Less than 140ft
<5 Thunderstorm days per year
©2003
Standards National Electric Code (NEC) Underwriters Laboratory (UL)
UL497 – Primary UL497A – Secondary
Installed in series between the primary protector and the equipment
Must safely limit over currents
©2003
Standards National Electric Code (NEC) Underwriters Laboratory (UL)
UL497 – Primary UL497A – Secondary UL497B – Isolated Loop (Fire Alarm or Data
Circuit) For lines that are contained within a building and not
connected to the public network outside the building These devices protect against transients usually caused by
electrostatic discharge and electrical shock NOT INTENDED FOR LIGHTNING PROTECTION
©2003
Standards National Electric Code (NEC) Underwriters Laboratory (UL)
UL497 - Primary UL497A – Secondary UL497B – Isolated Loop (Fire Alarm or Data
Circuit) UL1449 – Transient Voltage Surge Suppressor
AC Power listing at 330V For electrical safety, NOT equipment safety
©2003
Risk Assessment Where is the facility (Lightning potential)?
What is the Power Quality?
Outside Extensions?
What is the Ground Quality?
How Critical is the System?
What Will It Cost to Replace the System?
©2003
Typical Install
CO LINES
MAIN BUILDING
CAMPUS BUILDING
Prim
ary Pro
tectio
nT
elco
De
marcatio
n
PBX
Sec
on
dar
y Sec
on
dary P
rim
ary P
rimary S
eco
nd
ary
©2003
“Bubble of Protection” Backwards Approach Three potential conductive paths
1) AC Power 2) Communications Lines (Telecom) 3) Ground System
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Bubble of Protection
LINE
EQUIP
LINE
EQUIP
LINE
EQUIP
LINE
EQUIP
LINE
EQUIP
C.O.
PRI
MARY
LINE
EQUIP
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Final Layout
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Bonding & Grounding Grounding: Establish 0V Reference Bonding: Maintaining 0V Reference
Two Point Resistance < 0.1Ω
Direct attachment to the closest point in the building’s electrical service grounding electrode system is preferred
90% of problems are due to improper grounding
Good grounds Structural Steel Electrical Service Panel
©2003
Bonding & Grounding Ground Impedance < 1Ω
Tightness of Connections (Check Annually) Length (Short as Possible) Number of Bends (Straight as Possible) Bend Radius (Generous) Size/Gauge
©2003
Bonding & Grounding Ground Impedance (Earth Gnd) < 1.0 ohms
Single Point Ground Racks Cable Trays Raised Floor Conduits Structural Steel Equipment Cold Water Pipe AC Panel
©2003
Bonding & Grounding Ground Impedance (Earth Gnd) < 1.0 ohms
Single Point Ground
Protect or Ground Unused Pairs
©2003
Bonding & Grounding Ground Impedance (Earth Gnd) < 1.0 ohms
Single Point Ground
Protect or Ground Unused Pairs
Use proper gauge wire (AWG) Receptacle ground for small systems TMGB for large systems
©2003
Ground Size
Pairs Fuseless Fused
1-2 12 14
3-6 10 14
7-25 6 6
Primary
Secondary Not specified by UL or NEC Check Manufacturer’s Specifications Depends on size of system and current carry
capacity
©2003
Example – Airport Installation
The damaged phone switch
©2003
Example – Airport Installation
A Good Single Point Ground But…
©2003
Example – Airport InstallationIn Another Room, the Ground Wire… IT’S NOT CONNECTED TO ANYTHING!
©2003
Don’t let this happen Don’t let this happen to your systemto your systemDon’t let this happen Don’t let this happen to your systemto your system