Electrical Safety ProgramRefresher Training

In Compliance with NFPA 70E, 2009

Standard for Electrical Safety in the Workplace

Definition of Hot Work

• Any work on electrical equipment, circuits, devices, systems, or any other energized part(s) where an employee is required to deliberately, or could accidentally, place any part of his body, tool or material into or around such electrical devices where the voltage has been deemed to be in excess of 50 volts.

Why 50 Volts?

• OSHA and NFPA 70E have determined that the threshold for dangerous electrical potential is 50 volts.

• WHY?• The average human has 10,000 ohms of

resistance in our skin. • Currents of .005 amperes can be fatal.• Ohms law: 50 volts / 10000 ohms= .005 A

Study of Electrical Accidents

• Study was done base on serious electrical accidents that occurred to professional electricians during the discharge of their professional duties.

• An electrical accident was defined as an accident that was caused by contact or close proximity with electrical energy that was discharged in a manner not compliant with the circuit or system’s design.

Study of Electrical Accidents

• A serious accident was defined as any accident that resulted in 6 months lost time up to and including a fatality.

• There were 178 accidents that fell into this category in 1998.

Category Break Down

Distribution Equipment: 4%Overhead Power Lines: 3%Devices Mounted Below 8’: 31%Devices Mounted Above 8’: 59%Other Accidents: 3%

Interesting Statistics

• 90% of the accidents occurred while doing every day electrical tasks

• 81% of the accidents occurred to electricians with 8 plus years of experience.

Ask yourself why the majority of these serious accidents occurred

to experienced electricians.

The Hazards of Electricity

• Electrical Shock• Burns• Arc Blast• Arc Flash

Electrical Shock

• Short Term Effects– Heart Failure– External Burns– Internal Burn– Cellular Degradation– Autonomic System

Failure– Ventricular Fibrillation– Muscle Contractions

• Long Term Effects– Nervous system

disorders– Heart Damage– Heat Murmur– Brain Chemical

Imbalance– Muscle Ticks– Muscle Damage

Effects of Current on the Body

• Five primary factors affect the severity of the shock a person receives when he or she is a part of an electrical circuit: – Amount of current flowing through the body

(measured in amperes). – Path of the current through the body. – Length of time the body is in the circuit.– Contraction position of the heart– Chemical cycle of the body

Safety BASICs TM

Shock

(A) Touch Potential (B) Step Potential (C and D) Touch / Step Potential

Current passing through the heart and lungs is the most serious

Other Factors

• The voltage of the current. • The presence of moisture in the environment. • The general health of the person prior to the

shock • The resistance of the person shocked

Safety BASICsShock (Resistance Table)

TM

Effects of Current• Current level (in milliamperes) and Probable effect on human body • 1 mA Perception level. Slight tingling sensation. Still dangerous under certain

conditions. • 5 mA Slight shock felt; not painful but disturbing. Average individual can let go.

However, strong involuntary reactions to shocks in this range may lead to injuries. Ventricular fibrillation can occur at this level.

• 6-30 mA Painful shock, muscular control is lost. This is called the freezing current or "let-go" range.

• 50-150 mA Extreme pain, respiratory arrest, severe muscular contractions. Individual cannot let go. Death is possible.

• 1000-4300 mA Ventricular fibrillation (the rhythmic pumping action of the heart ceases.) will occur. Muscular contraction and nerve damage occur. Death is most likely.

• 10,000 mA Cardiac arrest, severe burns and death almost certain.

Energized Work

• Is usually preformed on equipment that is not protected by GFCIs.

• Even a 15 ampere circuit break will not trip until an overload of 15001 milliamperes is felt in the human body.

• Far Beyond the Survival Current.

Types of Burns• First-degree burns include only the outer layer of

skin. The skin may be red. The skin may also hurt when touched. These are mild burns and usually heal in a few days.

• Second-degree burns are deeper and more severe. Blisters may form on the burned area. The skin feels very tender when touched. This burn takes about 2 weeks to heal.

• Third-degree burns are the deepest and most dangerous. The skin is tough or leathery. It may look white, brown, black, or red. You may not feel anything when the burned skin is touched

Effects of Electrical Burns

• Immediate Effects– Pain– Deformity– Nerve Damage– Oral Cavity Damage– Genital Damage

• Long Term Effects– Bone Damage– Nerve Damage– Organ Failure– Teeth and Gum Failure

Arc Blast and Flash

• The third hazard of electricity is the most powerful and dangerous, yet the least talked about in electrical circles.

• It was not officially recognized until 1995. • It was not widely studied until 1997.

• We now understand it very well, perhaps, too well.

Arc Blast

• What is an electrical arc. – Current flowing through an area that was once

filled with air.

• What causes an arc? HEAT– Electrical conductors coming into contact and

breaking contact– Electrical conductors coming into close contact– Environmental conditions

Effects of Arc Blast

• An electrical arc burns at between 20,000 and 32,000 degrees F. – That is twice the center of a nuclear explosion. – That is four times the surface temperature of the

sun

• The average electrical arc lasts for 4-6 cycles from beginning to end.

Expansion of Material

• Matter changes shape with temperature as it goes from solid to liquid to gaseous forms.

• Water expands 4 times when it goes from liquid to gaseous form.

• Copper expands nearly 67,000 times in volume when it goes from solid to gaseous form.

• This happens in less than a 10th of a second.

Shock Wave

• Due to this expansion of material, a shock wave that measures approximately 600 lbs of pressure per square inch moves outward from the arc.

• Anyone in this blast area will be moved out of the blast area, forcefully.

Cooper Bussman Studies

• Cooper Bussman and many other companies have done extensive testing of arc blasts since 1997.

• The following slides demonstrate the power of an arc blast in a standard piece of equipment.

Electrical Arc

Copper Vapor:Solid to VaporExpands by67,000 times

Intense Light

Hot Air-Rapid Expansion

35,000 °F

Pressure Waves

Sound Waves

Molten Metal

Shrapnel

Personnel Hazards Associated with Arc Flash

Heat – Burns & Ignition of Materials Arc temperature of 35,000 ºF Molten metal, copper vapor, heated air

Second Degree Burn Threshold :80 ºC / 175 ºF (0.1 sec), 2nd degree burn

Third Degree Burn Threshold:96 ºC / 205 ºF (0.1 sec), 3rd degree burn

Intense LightDamage eyes – cataracts

Personnel Hazards Associated with Arc Flash

Pressures From Expansion of Metals & AirEardrum Rupture Threshold

720 lbs/ft2

Lung Damage - Threshold1728 - 2160 lbs/ft2

Shrapnel Flung Across Room or From Ladder/Bucket

IEEE/PCIC & NFPA 70EArc Flash Hazard

Arc Flash Hazard

• Following are some of the tests run by IEEE Ad Hoc Safety Committee

•All of the devices used for this testing were applied according to their listed ratings

Setup Area For TestsSetup Area For Tests

• A standard electrical room set up

• The test will be performed on a relatively low hazard area. – Not the switchgear– 30A disconnect

Close-up of Test AreaClose-up of Test AreaA

rc-F

lash

22.6 KA SymmetricalAvailable Fault Current

@ 480V, 3 Phase

Fault Initiated on Line Side of 30AFuse

30A RK-1Current Limiting Fuse

Size 1 Starter

Test Info6 cycle STD

640A OCPDNon Current Limitingwith Short Time Delay

Set @ 6 cycle opening

TEST

TEST Arc Blast Begins

TEST : Molten Copper

TEST: Copper vapor leads to a second blast in gutter

TEST: Second blast fire ball

TEST: Metal, copper and PVC continue to burn

TEST: Room enveloped in toxic smoke

22.6 KA SymmetricalAvailable Fault Current

@ 480V, 3 Phase

Fault Initiated on Line Side of 30AFuse

30A RK-1Current Limiting Fuse

Size 1 Starter

640A OCPDNon Current Limitingwith Short Time Delay

Results:Test

Opened in six cyclesNo CurrentLimitation

> 225 C /437 F> 225 C /

437 F

Results: Test

T1

T2

P1

T3

Sound

141.5 db @ 2 ft.

50 C / 122 F

>2160 lbs/sq.ft

> Indicates Meter Pegged

How Do We Protect Ourselves

• Use the STOP Principal

–Stop–Think–Options–Protections

Lock Out/ Tag Out

• We will discuss methods of protecting you from the hazards of electricity later in the class.

• The best method of protection is to de-energize the circuit.

The ESP

• Now let’s review the Electrical Safety Policy and How it will be used to help reduce the effects of electrical hazards.

• The ESP is based on NFPA 70E. The Standard for Electrical Safety in the Workplace.

NFPA 70E

• First published in 1997• Published by the NFPA• Updated in 2000, 2004 and 2009. • Now a part of the NEC code making process

and formatted in the same manner.

OSHA and NFPA 70E

• Six states have adopted NFPA 70E as the basis for electrical safety.

• The Federal OSHA requirements are in the process of being modified to meet NFPA 70E standards.

• NFPA 70E can be used by OSHA compliance officers now as a basis for a citation.

Overview of Safety Policy

• The policy can be broken into three parts– Administration– Hazard Prevention– Hazard Control

Policy Requirements

• All employees are required to read the entire policy and make themselves familiar with the requirements of the policy.

• Ask your supervisor if you do not understand any of this policy.

Policy Overview

• In this course we will cover some of the requirements of the electrical safety policy.

Personal Protective Equipment

• Gloves• Tools• FR Clothing– Double Layered– All Cotton unclothing

• Eye protection• Face protection• Ear protection

Selection of Equipment

• All personal protective equipment shall be selected based on the NFPA 70E charts provided in the electrical safety policy.

• You can download this chart from the main module page.

Authorization

• No energized work may take place until a completed Energized Work Form has been submitted and approved by the site superintendent, the project manager, the Director of Education and Loss Prevention and either the Director of Service or the VP of Operations.

• The Energized work form must be completed in detail and completely.

Hazard Risk Analysis

• The most important part of protecting ourselves is to identify the hazards and find means to reduce and control those hazards.

• We accomplish this with the Hazard Risk Analysis.

• A hazard risk analysis example is included in the Electrical Safey Policy. Be sure to download this from the module and read it.

Avoiding The Situation

• Ensure that power is locked out and tagged• Ensure temporary power panels are locked so

that only E Light Personnel may operate• Ensure that only qualified and authorized

personnel energize circuits• Ensure that all terminations are completed in

a safe manner prior to energizing any circuits. – Never Assume

Review of Policies

• We will discuss the Electrical Safety Policy and the Safety Plan for Solaris Project Regarding the Energizing of Electric Systems

• No work may occur or any circuit may be energized unless all of the conditions and procedures of the Safety Plan for Solaris Project Regarding the Energizing of Electric Systems have been successfully accomplished

“Do Not Tell Me It’s Dangerous.”

• Most electricians inform customers that it is dangerous to work on live equipment and circuits.

• They already know this. That is why they call us. • We have to show them the risks they are taking

when we work energized. • We need to ensure our clients are satisfied with our

work but we are also the experts in the electrical field. It is our responsibility to inform them of unsafe conditions.

Our Responsibility

• We are the electrical experts– We must say no when we are requested to do

something that is unsafe– We must say no when we are asked to circumvent

the procedure or policy, even if it is just one time, and even if it is “urgent or important.”

– The Weitz Company and Helix E Light have agreed to implement this policy on the jobsite and both companies have agreed to follow the procedures to improve the electrical safety on the project.

The Risks of Not Following the Procedures

• Injury or Fatality• Uncontrolled shutdown• OSHA Investigation• Replacement of parts• Downtime to make repairs• Monetary damages

Summary

• Electricity is the most powerful force commonly used by mankind.

• We as electricians are exposed to it’s energy more than anyone else.

• We must take every precaution to ensure our safety and the safety of others.

• We want you to go home the same way you came to work.

S.T.O.P.

When an electrician makes a mistake, people can die….

Including the electrician!!!!

• Return to the module main page and complete the test.

• Thank you,

• Ted Smith