Hazards and Risks when working with Electricity. What is the best way to prevent the hazards of...

Hazards and Riskswhen working with

Electricity

What is the best way to

prevent the hazards of

electricity?

Avoiding energized circuits is the safest way!

STOP

Think before taking

Action

THINK

About the

Risks and Hazards

OPTIONSDo you have options like:

LOTO (Lockout/Tagout)

PROTECTIONAre you wearing PPE?

(Personal Protective Equipment)

What are the

Hazards and Risks?

1. Shock

2. Arc Flash & Arc Blast

3. Fire Ignition

Shock and its EffectsImmediate:

1. Muscle contraction

2. Vital organs damaged

3. Tingling

4. Pain

5. Breathing

6. Disorientation

7. Dizziness

8. Possible death

Shock and its Effects

Long Term:

1. Memory Loss

2. Nervous disorders

3. Chemical imbalances

4. Damage to vital organs

5. Sometimes fatal

Effect of Current on the BodyMEN

• Perception Threshold

0.001 Amps (1 mA)• Painful Shock

0.009 Amps (9 mA)• Cannot Let-Go Level

0.010 Amps (10 mA)• Ventricular Fibrillation

.100 Amps (100 mA)• Heart Failure

0.5 Amps (500 mA)• Organ Burn

1.5 Amps (1500 mA)

WOMEN• Perception Threshold

0.0007 Amps (0.7 mA)• Painful Shock

0.006 Amps (6 mA)• Cannot Let-Go Level

0.010 Amps (10 mA)• Ventricular Fibrillation

.100 Amps (100 mA)• Heart Failure

0.5 Amps (500 mA)• Organ Burn

1.5 Amps (1500 mA)

Two Types of burns from Shock

Surface Burns:

Caused by entrance and exit of electrical currents through the body

Can be caused by a very small amount of current

1st degree to 3rd degree

Two Types of burns from Shock

Internal Tissue Burns:

Caused by current flowing through organs of the body

Caused by currents in excess of 1.5 amps

4th degree (internal) Internal organs Typically Fatal

How to prevent Shock

1. Place circuits in an Electrically Safe

Working Condition by Locking Out and

Tagging Out all sources.

2. Verifying that no electrical energy is

present.

NFPA 70 - NEC

1. The original and primary mission of the

NFPA 70 – NEC covered installation of

electrical systems.

2. The NFPA 70 – NEC does NOT

address the other hazards of electricity.

Exposure to Danger

1. The NEC protects individuals from shock

hazards under normal conditions.

2. It is NOT designed to protect us from

abnormal conditions.

3. We need additional policies to protect

from abnormal conditions.

Normal Conditions

1. Panel covers in place.

2. Equipment plugged in normally.

3. Normal designed protection in place.

Abnormal Conditions

1. Panel covers removed.

2. Equipment temporarily wired.

3. Normal designed protection such as

guards, limits switches, etc. NOT in

place.

Protection from

Abnormal Conditions

The Company

NFPA 70E

OSHA

Electrical Safety Procedures Manual

Electrical Safety Training

Protection from

Abnormal Conditions

YOU

The first line of defense.

Only you can truly keep you safe.

Implement Safety Procedures Outlined in the Safety Manual.

Only you can ensure that you go home at night.

Arc Flash

&

Arc Blast

Arc Flashis a high intensity flash which

will also create a very loud

noise (blast).

The Arc Flash produces:

Electric arc that produces the highest

temperatures on earth – up to 35,000oF (4 x

temp. of the sun).

The intense heat causes the sudden

expansion of air that results in a blast.

All known materials are vaporized at this

temperature (copper expands 67,000 times,

water 1,670 times).

Arc Flash & Blast

Relative to the human body:

A 2nd degree burn threshold, or a ‘just curable

burn threshold,’ is skin temperature raised to

175oF for 0.1 second.

A 3rd degree burn threshold, or ‘incurable burn

threshold,’ is skin temperature raised to 200oF

for 0.1 second.

Eardrum damage > 720 psf

Lung damage > 1728 psf

Arc Flash & Blast

Relative to the human body:

The hazard may be small for systems of

less than 300 volts with limited fault current.

Any system over 300 volts probably has the

capability to have significant arc flash

event.

Circuit Breaker Trips

When a circuit has been de-energized by a

protective device, DO NOT manually re-

energize the circuit without first

investigating the cause. Do not perform

repetitive manual re-closing of breakers or

replacing of fuses.

Circuit Breaker Operation With Covers

on and voltages less than 600V ac rms

Safety Glasses

Natural Fiber Long

Sleeve Shirt

Natural Fiber Long Pants

Stand to the side

Fused Switch Operation With Covers

on and voltages less than 600V ac rms

Safety Glasses

Natural Fiber Long

Sleeve Shirt

Natural Fiber Long Pants

Stand to the side

FIRE IGNITION

Clothing can be ignited several feet away

unless flame resistant (FR) or arc rated

(AR) clothing is worn.

Note: Synthetics burn ‘into’ the skin when

ignited.

Clothing

There is FR (flame resistant) clothing and

AR (arc rated) clothing.

ALL clothing with an arc rating (AR) is flame

resistant (FR), but not all flame resistant

clothing has an arc rating.

Clothing

Prior to 2015, untreated cotton was

considered a safe fabric to wear.

Beginning with the change to NFPA – 70E

in 2015, arc rated (AR) clothing is required

as you will see later in this presentation.

Now that you are aware of:

shock, arc flash and arc blast,

and fire ignition, what do you do

about it?

Protect Yourself

Protect Yourself Against

1. Shock Hazard

2. Arc Flash and Arc Blast Hazard

3. Fire Ignition

SHOCK Hazard

What is required?

1. Determine the Operating Voltage of the

System.

2. Determine Shock Protection Boundaries.

3. Determine the Personal Protective

Equipment.

SHOCK Hazard

1.Determine the Operating Voltage of the

System.

SHOCK Hazard2.Determine Shock Protection Boundaries.

a. Limited Approach Boundary –

b. Restricted Approach Boundary –

Approach Boundaries

Limited Approach Boundary –

An approach limit at a distance from an

exposed energized electrical conductor or

circuit part within which a shock hazard exists.

Approach Boundaries

Restricted Approach Boundary –

An approach limit at a distance from an

exposed energized electrical conductor or

circuit part within which there is an increased

likelihood of electric shock, due to electrical

arc-over combined with inadvertent movement,

for personnel working in close proximity to the

energized electrical conductor or circuit part.

Approach Boundaries for Alternating Current Systems

Phase-to-Phase

Voltage

LimitedApproachBoundary

Fixed

RestrictedApproachBoundary

Lessthan50

Notspecified

Notspecified

50 – 150 3 ft. 6 in. Avoidcontact

151 – 750 3 ft. 6 in. 1 ft. 0 in.

Qualified Person

One who has demonstrated skills and

knowledge related to the construction and

operation of electrical equipment and

installations and has received safety

training to identify and avoid the hazards

involved.

SHOCK Hazard

3. Determine the Personal Protective

Equipment.

a. Use Voltage Rated (VR) Gloves rated

greater or equal to the voltage of the

system.

b. Use Voltage Rated (VR) Tools rated

greater or equal to the voltage of the system.

OSHA and NFPA 70E both state that

qualified electrical workers shall not be

asked to work on equipment that is ‘hot’

or ‘live’ except for two demonstrable

reasons:

1. De-energizing introduces additional

or increased hazards, like an

emergency alarm system or a ventilation

system.

2. Infeasible due to equipment design

or operational limitations, like voltage

testing for diagnostics or start up

testing. Note: This is the HVACR

trade.

Conclusion

When you work on ‘live’ circuits, you are

open to the hazards and risks of electricity.

Therefore, you need to take on the

responsibility of protecting yourself. So,

how can this be done?

NFPA 70E Hazard/Risk Categories

• Prior to 2015, NFPA 70E classified

electrical hazards and risks from 0 to 4.

• In 2015, Category 0 was eliminated.

• The name ‘Hazard/Risk’ was changed to

‘Arc Flash PPE.’

Arc Flash PPE

or

Incident Energy Analysis

Methods

How do you select the PPE?

• Prior to 2015, selection of PPE was

based on Hazard/Risk Categories 0 – 4.

• In 2015, selection of PPE is based on

either the Incident Energy Analysis

Method or Arc Flash PPE Category

Method, but not both.

How do you select the PPE?

• The Arc Flash PPE Category Method is

the simpler of the two and that is what

this program will focus on.

• Before we look at the actual categories,

let’s take a look at some tasks and find

where Arc Flash PPE is required.

Table 130.7(C)(15)(A)(a) Arc Flash Identification forAlternating Current (ac) and Direct Current (dc) Systems

Task Equipment ConditionArc Flash

PPERequired

Reading a panelmeter operatinga meter switch.

Any No



PPERequired

Normal operation of acircuit breaker (CB),switch, contactor, or

starter

All of the following:

The equipment is properly installed.The equipment is properly maintained.All equipment doors are closed and secured.All equipment covers are in place and secured.There is no evidence of impending failure.

No

One or more of the following:

The equipment is NOT properly installed.The equipment is NOT properly maintained.Equipment doors are open or NOT secured.Equipment covers are off or NOT secured.There is evidence of impending failure.

Yes



PPERequired

For Alternating Currentsystems: work on

energized electricalconductors and circuit

parts, includingvoltage testing.

Any

Yes

Any

Yes

Removal orinstallation of

CBs or switches.



PPERequired

Removal or installationof covers for equipment

such as wireways,junction boxes, and

cable trays that does not expose bare

energized electricalconductors and

circuit parts.

All of the following:

The equipment is properly installed.The equipment is properly maintained.There is no evidence of impending failure.

No

Any of the following:

The equipment is NOT properly installed.The equipment is NOT properly maintained.There is evidence of impending failure.

Yes



PPERequired

Removal of boltedcovers (to expose bare

energized electricalconductors and circuit

parts.)

Any

Yes

Yes

Opening hinged door(s)or cover(s) to expose

bare energizedelectrical conductors

and circuit parts.

Any



PPERequired

Work on control circuitswith exposed energized

electrical conductorsand circuit parts, 120 volts or belowwithout any other

exposed energizedequipment over 120 Vincluding opening of

hinged covers to gain access.

Any

No



PPERequired

Work on control circuitswith exposed energized

electrical conductorsand circuit parts,

greater than 120 V.

Any

Yes

Work on exposedenergized electrical

conductors and circuit parts of

equipment directly supplied by a

panelboard or motor control center.

AnyYes

Table 130.7(C)(15)(A)(b) Arc-Flash Hazard PPE Categories

(Panelboards or other equipment rated 240 v and below)

Parameters:

Maximum of 25 kA short-circuit current available

Maximum of 0.03 sec (2 cycles) fault clearing time

Working distance: 18 inches

Arc Flash PPE Category: 1

Arc Flash Boundary: 19 inches

Table 130.7(C)(15)(A)(b) Arc-Flash Hazard PPE Categories

(Panelboards or other equipment rated >240 v and up to 600V)

Parameters:

Maximum of 25 kA short-circuit current available

Maximum of 0.03 sec (2 cycles) fault clearing time

Working distance: 18 inches

Arc Flash PPE Category: 2

Arc Flash Boundary: 3 feet

ARC FLASH BOUNDARY

The arc flash boundary shall be the distance at which the

incident energy equals 1.2 cal/cm2

Arc Flash PPE Category 1 has a boundary of 19 inches.

Arc Flash PPE Category 2 has a boundary of 3 feet.

What does this mean?

Incident Energy

cal/cm2

Degree Burn

1.2 2nd degree burn to bare skin

Arc Flash Boundary is related to Incident Energy.

4 Ignite a cotton shirt

8 3rd degree burn to skin

Incident

Energy

cal/cm2

Degree Burn

1.2 2nd degree burnto bare skin

Arc Flash Boundary is related to Incident Energy.

CONCLUSION

PPECategory 1

PPECategory 2

19 inches 3 feet

PPE Category 1Arc Rated Clothing, Minimum Arc Rating of 4 cal/cm2

•Arc rated long sleeve shirt and pants or arc rated coverall•Arc rated face shield or arc flash suit hood•Arc rated jacket, parka, rainwear, or hard hat liner (AN)

Protective Equipment•Hard hat (for Industrial Workers)•Safety glasses or safety goggles•Hearing protection (ear canal inserts)•Heavy duty leather gloves or combination of rubber insulating gloves with leather protectors•Leather footwear (AN)

PPE Category 2Arc Rated Clothing, Minimum Arc Rating of 8 cal/cm2

•Arc rated long sleeve shirt and pants or arc rated coverall•Arc rated face shield or arc flash suit hood and arc rated balaclava•Arc rated jacket, parka, rainwear, or hard hat liner (AN)

Protective Equipment•Hard hat (for Industrial Workers)•Safety glasses or safety goggles•Hearing protection (ear canal inserts)•Heavy duty leather gloves or combination of rubber insulating gloves with leather protectors•Leather footwear (AN)

Equipment Labeling

GLOVES

Class of Equipment

Maximum Use

Voltage (AC)

Proof Tested (VAC)

Proof Tested (VDC)

00 500 2,500 10,000

0 1,000 5,000 20,000

1 7,500 10,000 40,000

2 17,000 20,000 50,000

3 26,500 30,000 60,000

4 36,000 40,000 70,000

Meter Requirements

CAT III or CAT IV

Who is Responsible for Electrical Safety?

Employers are required to:

Select appropriate PPE based on the hazards present or

likely to be present in the workplace.

Prohibit the use of defective or damaged PPE.

Require that employees be trained so that each affected

employee can properly use the assigned PPE.

NFPA 70E Enforcement

The practical result of complying with the safe work

practices defined in NFPA 70E is, in most cases,

complying also with the applicable OSHA

regulations.


Compliance is not mandatory, so OSHA safety and health

compliance officers do not enforce NFPA 70E per se. But

you can be cited for not complying with the standard.

There is a growing tendency for them to rely on NFPA 70E

under the so-called ‘general duty’ clause.


The OSHA ‘general duty’ clause as found in

Section 5 (a)(1) of the Occupational Safety and

Health Act requires employers to furnish safe

workplaces that are free from recognized hazards

that are causing, or are likely to cause, death or

serious physical harm to employees.

Response

to an

Electrical Accident

Response to an Electrical Accident

1. The first step must be to ‘TURN THE

POWER OFF’

2. Remember that Speed is Essential

3. Extinguish flames

4. Call for Help (911)

5. Begin CPR & First Aid

Response to an Electrical Accident

First Aid

a. Cool the burn with water.

b. Do not attempt to remove burned clothing.

c. Elevate burned limbs.

d. Handle the victim with care.

e. Treat for shock.

Conclusion

When you work on ‘live’ circuits, you are

open to the hazards and risks of electricity.

Therefore, you need to take on the

responsibility of protecting yourself.

VIDEOS

SHORTED

20kA circuit

100 Amp

Disconnect

Switch Gear

ExplosionPlease watch carefully as to when

the worker puts his face shield

down and the explosion.

Switch Gear

ExplosionThere are 3 workers. Watch for

the one that is squatting between

the other 2 during the explosion.

The camera on the roof saw it all.

Breaker

Disconnect

on Roof

What are some things he could have

done to better protect himself?

Tech Electrocuted Changing Air Filter

1. Heat Pump Service Call.

2. Checked out the equipment in the attic and

outside.

3. Went under the house to change the air filter.

4. Touched the air handler cabinet, became locked

and grounded by a wire that was shorted to the

air handler’s metal cabinet.

5. He was LOCKED to the air handler and after

some 15 minutes the homeowner called him.

6.When he did not answer, the owner went under

and found him and was able to knock him off the

unit and freed him.

7.The owner dragged him out and started CPR.

8.EMS arrived and continued CPR on the way to

the Medical Center, where medical staff continued

CPR, but a doctor pronounced him dead.


What are some things he could have

done to better protect himself?


A novel way of taking

a selfie that ended

badly.

YOU need to

RESPECT

electricity and

BE SAFE.

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