# Presentation: 607898

## Electrical Hazards Awareness Briefing

- Basic Electrical Safety Hazard Awareness for
- Non-Electrical Personnel
- Module 1

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**Notes:**
It is very important that all employees review this procedure and become familiar with the practices outlined herein

## Purpose

- The purpose – worker safety
- Raising your awareness of electrical hazards
- Instructing you on how to recognize electrical hazards
- Providing ways to eliminate, remove and prevent electrical hazards in the workplace
- Emphasizing the extreme importance of observing all electrical safety requirements and practices
- Instructing you on what to do during an electrical accident

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**Notes:**
Purpose
This procedure defines responsibilities and requirements so that personnel can recognize electrical hazards and avoid injury or fatality.

In addition to this briefing, read through the procedure carefully and contact your SERB representative if you have any questions.

## Introduction

- An average of one worker is electrocuted on the job every day
- An average of one person is electrocuted in the home every 36 hours
- Electrical incidents are far more likely to be fatal than other types
- There are four main types of electrical injuries:
- Electrocution (death due to electrical shock)
- Electrical shock
- Burns
- Falls

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**Notes:**
This module addresses OSHA’s General Industry electrical standards contained in 29 CFR 1910 Subpart S.  OSHA also has electrical standards for construction and maritime, but recommends that employers in these industries follow the general industry electrical standards whenever possible for hazards that are not addressed by their industry-specific standards.

Suitability of electrical equipment for an identified purpose may be evidenced by listing or labeling by a nationally recognized testing laboratory which makes periodic inspections of equipment production and states that such equipment meets nationally recognized standards or tests to determine safe use in a specified manner.

The Lockout/Tagout (LOTO) standard, 29 CFR 1910.147, is not covered in this presentation.  However, you can find information on the Lockout-Tagout Interactive Training Program, under “OSHA Advisors” on the OSHA web site, www.osha.gov.

Electricity is one of the most common causes of fire in homes and workplaces.  Explosions have also resulted from electrical sources.

## Electrical Terminology

**Current** – the movement of electrical charge
**Resistance** – opposition to current flow
**Voltage** – a measure of electrical force
**Conductors** – substances, such as metals, that have little resistance to electricity
**Insulators** – substances, such as wood, rubber, glass, and bakelite, that have high resistance to electricity
**Grounding** – a conductive connection to the earth which acts as a protective measure

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**Notes:**
Operating an electric switch is like turning on a water faucet. Behind the faucet or switch there must be a source of water or electricity with something to transport it, and with a force to make it flow. In the case of water, the source is a reservoir or pumping station; the transportation is through pipes; and the force to make it flow is provided by a pump. For electricity, the source is the power generating station; current travels through electric conductors (wires); and the force to make it flow - voltage, measured in volts, is provided by a generator.

Resistance
- Dry skin has a fairly high resistance, but when moist, resistance drops radically, making it a ready conductor.
- Measured in ohms.

Use extra caution when working with electricity when water is present in the environment or on the skin.  Pure water is a poor conductor, but small amounts of impurities, such as salt and acid (both are contained in perspiration), make it a ready conductor.

## Electrical Shock

- Received when current passes through the body
- Severity of the shock depends on:
- _Path_ of current through the body
- _Amount of current_ flowing through the body
- _Length of time_ the body is in the circuit

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**Notes:**
A small current that passes through the trunk of the body (heart and lungs) is capable of causing severe injury or electrocution.

Low voltages can be extremely dangerous because, all other factors being equal, the degree of injury increases the longer the body is in contact with the circuit.

## Dangers of Electrical Shock

- Currents greater than 75 mA* can cause ventricular fibrillation (rapid, ineffective heartbeat)
- Will cause death in a few minutes unless a defibrillator is used
- 75 mA is not much current – a small power drill uses 30 times as much

- * mA = milliampere = 1/1,000 of an ampere

*Defibrillator in use*

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## How is an electrical shock received?

- When two wires have different potential differences (voltages), current will flow if they are connected together
- In most household wiring, the black wires are at 110 volts relative to ground
- The white wires are at zero volts because they are connected to ground
- If you come into contact with an energized (live) black wire, and you are also in contact with the white grounded wire, current will pass through your body and YOU WILL RECEIVE  A SHOCK

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**Notes:**
Grounding is a physical connection to the earth, which is at zero volts.

Electricity travels in closed circuits, and its normal route is through a conductor. Electric shock occurs when the body becomes a part of the  circuit.  Electric shock normally occurs in one of three ways - when an individual is in contact with the ground and contacts: 
  1.  Both wires of an electric circuit, or
  2.  One wire of an energized circuit and the ground, or 
  3.  A metallic part that has become energized by contact with an energized conductor.  The metal parts of electric tools and machines may become energized if there is a break in the insulation of the tool or machine wiring.  A worker using these tools and machines is made less vulnerable to electric shock when there is a low-resistance path from the metallic case of the tool or machine to the ground. This is done through the use of an equipment grounding conductor—a low-resistance wire that causes the unwanted current to pass directly to the ground, thereby greatly reducing the amount of current passing through the body of the person in contact with the tool or machine.  

## How is an electrical shock received?(cont’d)

- If you are in contact with an energized wire or any energized electrical component, and also with any grounded object, YOU WILL RECEIVE A SHOCK
- You can even receive a shock when you are not in contact with a ground
- If you contact both wires of a 240-volt cable, YOU WILL RECEIVE A SHOCK and possibly be electrocuted

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**Notes:**
Contact with both energized wires of a 240-volt cable will deliver a shock.  This type of shock can occur because one live wire may be at +120 volts while the other is at –120 volts during an alternating current cycle, which is a potential difference of 240 volts.

## Low Voltage Does Not Mean Low Hazard

- A small amount of electrical current can cause injury, even death
- The current from a 7.5-watt, 120-volt lamp, passing across the chest, is enough to cause fatal electrocution
- Deaths from **120 volts** represent about 12 percent of all electrocutions

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## Electrical Burns 

- Most common shock-related, nonfatal injury
- Occurs when you touch electrical wiring or equipment that is improperly used or maintained
- Typically occurs on the hands
- Very serious injury that needs  immediate attention

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## Recognize the Hazards

**Have you seen areas like these?**

**Both are NEC violations and present a safety hazard, based on inaccessible circuit control devices**

- Do not block the working space around electrical equipment (600 volts, nominal, or less).  This space provides and maintains sufficient access and working space to permit ready and safe operation and maintenance of such equipment

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## Recognize the Hazards

**What do you do if you see these situations?**

**Call a timeout and inform your supervisor**

- Do not remove or open receptacle covers, switch plates, or covers of electrical equipment unless qualified and authorized

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## Recognize the Hazard

- Assume all exposed wiring is energized until proven otherwise.  STOP, protect the area and contact supervision if you encounter this situation

**Potentially energized exposed wire with status unknown**

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## Recognize the HazardTripping  and Abrasion Hazards

- Don’t cause tripping hazards or create pinch points for cords
- If you must run a cord temporarily across the floor, protect your co-workers by covering the cord appropriately

**Not OK**

**OK**

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## Recognize the Hazards

**Remove from service damaged or frayed cords**
**Report electrical equipment damage to your supervisor**

**Stay clear of bare, exposed wiring and REPORT IT!**

- Visually inspect electrical equipment before each use for damage and/or external defects such as loose, missing or deformed parts, pinched or crushed outer jackets or insulation.  This type of external damage may indicate internal damage to the equipment.
- Electrical cords that are worn or damaged must be replaced without delay.
- Before cleaning electrical equipment, turn it off and unplug it.

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## Recognize the Hazard Cabinets, Boxes, and Fittings

- Junction boxes, pull boxes and fittings must have approved covers in place
- Unused openings in cabinets, boxes and fittings must be closed (no missing knockouts)
- Photo shows violations of these two requirements
- Report this situation to management

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**Notes:**
1910.305(b)(1) and (2)

## Recognize the Hazards

**Never daisy chain multi-outlet strips (plugging into each other)**

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## Recognize the Hazard

- Observe all barricades, postings, and warning signs regarding dangerous voltages
- Do not enter or approach electrical work areas unless specifically authorized and qualified.

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## Recognize the Hazards

**Not permitted and should be taken out of service!**
**Electrical boxes with knockouts are designed to be installed in or on walls, not used as multi-outlet extension cords.**

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## Recognize the HazardGrounding Path

- The path to ground from circuits, equipment, and enclosures must be permanent and continuous
- Violation shown here is an extension cord with a missing grounding prong
- Do not make alterations to polarized blades or ground pin to make plug fit into non-polarized or non-grounded outlet

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**Notes:**
1910.304(f)(4)

## Recognize the Hazards

**Recognize the Hazards**

- Electrical hazards may exist overhead indoors
- Crane power rails are an example
- Electrical hazards may also exist overhead outdoors
- Most lines are bare and higher voltage than the “normal” insulated wiring
- Contact is not required to initiate an arc or cause shock and burn injuries
- Maintain safe approach distances when working near energized overhead lines

**Stay at least 10 feet away from overhead lines**

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## Recognize the Hazard

- Electrical equipment and wiring must not be exposed to physical damage
- Picture shown here is physical damage to conduit
- Stay away from damaged equipment and report equipment damage to supervision

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**Notes:**
1910.303(g)(2)(ii)

## Recognize the Hazard

- Treat it as it is designed to be treated
- Pull the plug, not the cord

- Handle portable electrical equipment carefully, in accordance with manufacturers instructions, and in a manner that will not cause damage

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**Notes:**
Over 3000 electrical fires are caused each year from faulty extension cords, resulting in 50 deaths and 270 injuries.

## Clues that Electrical Hazards May Exist  

- Tripped circuit breakers or blown fuses
- Hot to the touch on tools, wires, cords, connections, or junction boxes
- Dim and flickering lights
- Sizzles and buzzes-unusual sounds from electrical system
- Odor of hot insulation
- Mild tingle from contact with case or equipment
- GFCI that shuts off a circuit
- Worn or frayed insulation around wire or connection
- Burn marks or discoloration on receptacle plates or plug prongs

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## Ground-Fault Circuit Interrupter

- Always use a GFCI receptacle or circuit for cord connected tools and equipment used outdoors or near water
- This device protects you from electrocution
- The GFCI detects a difference in current between the black and white circuit wires
- 	(This could happen when electrical equipment is not working correctly, causing current “leakage” – known as a *ground fault.*)
- Perform the test function on the GFCI to determine if it is functioning properly by pushing the button to verify it shuts off
- Repeated resetting not allowed.  Contact local E&I to troubleshoot if GFCI continues to trip.

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**Notes:**
The GFCI continually matches the amount of current going to an electrical device against the amount of current returning from the device along the electrical path.

Whenever the amount of current going differs from the amount returning by approximately 5 milliamperes, the GFCI interrupts the electric power within as little as 1/40 of a second, protecting you from a dangerous shock.

GFCI’s are able to detect the loss of current resulting from leakage through a person who is beginning to be shocked.  If this situation occurs, the GFCI switches off the current in the circuit. 

GFCI’s are different from circuit breakers and fuses because they detect leakage currents rather than overloads.

## Prohibited Uses of Flexible CordsExamples

- Substitute for fixed wiring

- Run through walls, ceilings, floors, doors, or windows

- Concealed behind or attached to building surfaces

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## Safe PracticesCord Control

- Do not fasten electrical cords to surfaces with staples, nails, wire, or any other method that might damage the cord
- Extension cords
- Place them in appropriate locations
- Understand they are for temporary use only
- Tool cords
- Keep track of them, to assure they do not become damaged
- Do not plug or unplug electrical cords with wet hands or while standing in water

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## Safe PracticesCord Control Cont.

- Do not use portable electrical equipment or extension cords in wet or damp locations without a ground fault circuit interrupter (GFCI) ahead of the plug connection
- GFCIs are also required for temporary power applications in wet or damp locations, including extension cords
- Remove loads from an appliance or extension cord before unplugging it
- If a plug won’t stay placed snugly or fits loosely in a receptacle, don’t use it; call local E&I to replace it

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## Safe PracticesResetting Breakers

- When circuit breakers and fuses trip, don’t reset or replace them!
- Only qualified and authorized personnel are allowed to reset breakers and replace fuses
- Contact qualified personnel to determine the cause of trips

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## Safe PracticesConductive Apparel

- Don’t wear loose conductive apparel, (such as rings, watch bands, bracelets, necklaces, etc.) when plugging in electrical cords

**Burn from arc**

**Charm contacted plug**

**Charm contacted plug here**

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**Notes:**
The charm on this persons arm contacted the prongs of the plug as the person attempted to plug in a cord to  power strip, resulting in a electrical short circuit and arc that burned the arm.

## Safe PracticesWall Penetrations

- When penetrating walls to hang pictures, bulletin boards, signs, understand and follow site requirements to ensure that concealed electrical wiring, conduit or piping will not be contacted
- A non-obtrusive survey (e.g., Ground Penetrating Radar, proximity detection device) may be required, along with a review of applicable drawings, to ensure that the electrical system is not penetrated or contacted

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## Safe PracticesEquipment Applications

- Consumer electrical equipment or appliances should be tested and labeled by a recognized testing laboratory. (Look for the UL, CSA, ETL or MET Label)
- Always read and follow the manufacturers instructions carefully. Be sure that the equipment or tool is rated for the environment (wet, damp, etc.)
- Plug portable space heaters directly into outlet: Do not use extension cord.  Use a circuit with as little else on it as possible since space heaters take a lot of power.

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## Safe PracticesQualifications

- Do not remove/replace receptacle covers, switch plates, or covers of electrical equipment that may contain energized conductors without electrical qualifications and authorization
- Only qualified electrical workers may perform activities such as electrical probing, measuring and testing electrical energized components (such as performing an “absence of voltage” test)

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## Electrical Emergencies

- Do you know what dangers could be encountered?
- Attempts to rescue an accident victim may pose as great a hazard for the rescuer as it does for the victim
- A victim of an electrical accident is often unable to move or release the electrical conductor, because of muscle clamping
- Caution should be a primary consideration during any electrical accident or emergency

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## Electrical Emergencies

- Do you know the proper actions to take if you see someone receiving a shock or locked onto an energized electrical line?
- Approaching the accident:
- Never rush into an accident situation-Assess your own safety
- Call 911 as soon as possible
- Unplug portable electrical equipment to remove power (1st choice)
- Open a disconnecting device or circuit breaker to de-energize fixed electrical equipment
- Use a dry wood broom, leather belt, plastic rope, or something similar that is non-conductive such as wood or plastic cane with hook on the end to free the person from the energy source

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## Electrical EmergenciesDowned Power Lines

- Do you know the proper actions to take?
- Approaching the accident:
- Move away from downed power line
- Shuffle away with small steps keeping feet together
- If you see someone in direct contact with line, do not touch person
- Call 911 as soon as possible
- Do not attempt to move downed power line
- Get the aid of trained electrical personnel if possible
- If you are in your car and it is it contact with the downed line, stay in car.  Honk horn for help and tell others to stay away from your vehicle

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## What Now?

- Inspect your work areas
- Existing unsafe conditions
- Bare wires
- Open enclosures containing exposed wires
- Loose or missing covers or fasteners
- Use good electrical safe practices
- No daisy-chaining
- No overloading outlets
- Pull on plug, not cord

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## What Now?

- What do I do if I identify a hazardous condition?
- When unsafe electrical conditions are found, correct them if possible, or take steps to warn other employees
- Report unsafe electrical conditions verbally and/or in writing to supervision so corrective actions can be taken immediately
- Barricade the area, if an immediate hazard exists
- Notify supervision for correction and documentation

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## For More Information

- Contact:
- Your Site Electrical Safety Officer, or
- Your Safety Engineer
- WEB Sites
- See DOE Electrical Safety Campaign at _www.eh.doe.gov/paa/electrical_
- See Electrical Safety Foundation International at www.electrical-safety.org

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