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Electrical Safety and Electrical Safe Work

Practices

EHS Course #525Reference EHS Electrical Safety

Procedure 75-44

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Why Electrical Training?

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What Problems Do You See in Your work area?

• Damaged plug• Missing ground

pin• Shorted out – the

missing prong was found still in the outlet...

• Why is a missing ground pin a problem?

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What Problems Do You See in Your work area?

• Damaged GFCI outlet

• Why didn’t the GFCI prevent the damage?

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What Problems Do You See in Your work area?

• Spliced and taped cord on a lamp – fire and electrocution hazard

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Don’t do this at home.....Don’t do this at home.....

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Home Electrical Safety

• Never use lights with frayed cords, loose or bare wires, cracked or empty sockets.

• Do not connect more than 3 light sets together & do not overload extension cords (use an outlet strip with built-in overload protection).

• Turn off all Christmas lights prior to leaving your home or going to bed.

• Use only equipment that is UL listed and in good repair.• Do not use candles on or near your tree.• Test your smoke and carbon monoxide detectors, replace batteries.• If outdoors, use only electrical decorations certified for outdoor use &

keep clear from snow and water & use GFCI protected circuit.• Plug lights & decorations into circuits protected by GFCIs (ground

fault circuit interrupters).

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Installations

• All installations at BD shall meet the following code minimum requirements:– NFPA/NEC 70 (National Electrical Code)

– NFPA 79 (Electrical Standard for Industrial Machinery)

NOTE: If you don’t know what these two codes are, AND what they require, you have no business working on electrical equipment or opening an electrical cabinet…

• ONLY qualified Facilities Electricians may work on building electrical systems…

• Only qualified Electro-mechanics and qualified Engineers may work on production equipment electrical systems and components

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Why Follow the Rules?

• Electrical shock– What is the highest voltage on production

equipment here at BD – Sandy?– When was the last electrical shock incident (other

than static electricity) at BD – Sandy?

• Arc Flash hazard• Electrical fires• Electrical burns

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ELECTRICAL HAZARDS

• Misnomer: Electricity flows through the path of least resistance. (It flows through ALL paths…)

• Electric shock occurs when the human body becomes part of the path through which electrical current flows. – The direct result can be electrocution.– Burns can result when a person touches electrical

wiring or equipment that is energized– The indirect result can be injury resulting from a fall

or movement into machinery because of a shock.

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Arc Flash/ Arc Blast

• Occurs when high amperage current jumps a gap (short circuit) – such as when un-insulated tools are being used on live electrical circuits...

• Arc Flash / Arc Blast injuries was the number one source of electrical injuries, and has been for many years…

• An arc blast can occur when electrical cabinets/panels are open– Temperatures can be as high as 35,000 F– Metal, Molten metal, or other objects– Pressure Wave

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ELECTRICAL HAZARDS

• Explosions: Occur when electricity provides an ignition source for an explosive mixture in the air.– Flammable vapors– Dust (plastic dusts, grain dust, other organic material, metal

dusts,etc)

• Fires: Electricity is the most common cause of fires both in the home and in the workplace.– Defective or misused electrical equipment is a major cause.

• Electrically Classified Areas and Equipment: Never substitute parts, never make modifications without an Engineering Review!

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ELECTRIC SHOCKELECTRIC SHOCK

Effects of electric Effects of electric shockshock

depend on:depend on:

-- Current & voltage-- Current & voltage-- Resistance-- Resistance-- Path through body-- Path through body-- Duration of shock-- Duration of shock

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CURRENT & CURRENT & VOLTAGEVOLTAGE

As alternating current increases:• Tingling gives way to muscle contractions • Pain develops• Control of muscles becomes increasingly difficult• At 15 mA, victims cannot let go of the conductive surface• At 70 mA, ventricular fibrillation of the heart occurs (a typical circuit is 15 amps plus)• Death follows in a few minutes• Heavy current flow can also result in severe burns (internal & external) & heart paralysis

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BY-STANDERS AND AND APPROACH DISTANCESAPPROACH DISTANCES(AKA Electric Shock Protection Boundaries)(AKA Electric Shock Protection Boundaries)

Nominal System Voltage Range, Phase to Phase

Limited Approach Boundary

Restricted Approach Boundary

Prohibited Approach BoundaryExposed Movable

Conductor Exposed Fixed

Circuit Part 

Less than 50  36 in 36 in Avoid Contact Avoid Contact

50-300  10 ft 0 in 3 ft 6 in Avoid contact Avoid contact

301-750  10 ft 0 in 3 ft 6 in 1 ft 0 in 1 in

         

751-15 kV  10 ft 0 in 5 ft 0 in 2 ft 2 in 7 in

15.1 kV-36 kV  10 ft 0 in 6 ft 0 in 2 ft 7 in 10 in

36.1 kV-46 kV  10 ft 0 in 8 ft 0 in 2 ft 9 in 1 ft 5 in

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• Extension cords can be made ONLY by “Qualified Individuals” (see above…)

• Do not use gang plugs (wall mount box on end of extension cord with 2 or more outlets installed…)

• Do not use cords with broken ground prongs• Do not piggy-back surge protectors• Do not use zip cords (light weight household

type extension cords that do not have a secondary insulation sheath)

General Electrical Concerns

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General Electrical Concerns

• Keep all electrical equipment clear from water and moisture

• Building Circuit Breakers can be reset ONLY by Qualified Facilities Personnel

• The only persons authorized to open and do any work in an electrical cabinet on production equipment are:– Qualified Electro-mechanics– Qualified Engineers

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Don’t do this at Home....Don’t do this at Home....

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Did I Mention there is a QUIZ???

• The quiz is in the following location:

S:\Safety\Training 2008\Dec - Electrical