Bioelectrical Hazards and Electrical Safety

Ground

Refers to a conductive body and is a conductive connection by which an electric circuit or equipment is connected to earth or the ground plane.

Guarding

A type of isolation that uses various structures to close off live electrical parts.

Just a faint tingle

1 mA

Hazard recognition of electrical panels

1) Electric panels must be clear of obstructions. 2) Storage should not be placed in electrical panel rooms.

3 Primary Hazards associated with Arc-Blasts

1) Gives off thermal radiation (heat) and intense light. 2) Produces large pressure wave blast. 3) May cause copper and aluminum components to melt.

Electrical Hazard Protections

1) Insulation 2) Grounding 3) Guarding 4) Electrical protective Devices 5) Personal Protective Equipment 6) Safe Work Practices

Severity of electrical shock on the human body depends on...

1) Path of current through the body 2) Amount of current flowing through the body 3) length of time the body is in the circuit.

High voltage lead to additional injuries such as ....

1) Violent muscular contractions 2) Internal bleeding, destruction of tissues, nerves and muscles.

Hazard recognition of cords and equipment

1) Visually inspect electrical equipment 2) Electrical cords that are worn or damaged must be replaced. 3) Before cleaning electrical equipment, turn it off and unplug it.

Arrhythmic heart pumping action, muscles contract, and nerve damage occurs. Death is likely.

1,000-4,300 mA (1-4.3 A)

Cardiac arrest and severe burns. Death is probable.

10,000+ mA (10 A)

Slight shock felt, most people can let go.

5 mA

Extremely painful shock, respiratory arrest, and severe muscle contractions. Death is possible.

50-150 mA

Painful shock. Muscular control is lost. This is the range where "freezing current" starts. It may not be possible to let go.

6-30 mA

Temperatures of an Arc-Blast

>35,000 degrees

Grounding

A tool or electrical system, a low-resistance path to the earth is intentionally created.

Most common shock related, nonfatal injury

Burn

Unused openings in cabinets, boxes and fittings must be ....

Closed

If you must run a cord temporarily across the floor ...

Cover the cord appropriately.

Junction boxes must have approved ______ in place

Covers

Never ______ ______ multi-outlet strips

Daisy chain

Ground Fault Circuit Interrupters (GFCI)

Detects difference in current between 2 circuit wires. Set at ~ 5 mA and designed to protect workers, NOT equipment.

4 major types of electrical injuries

Direct: Electrocution, Electrical Shock, Burns. Indirect: Falls

3 types of burns

Electrical burns, arc burns, thermal contact burns

Assume all exposed wiring is ...

Energized until proven otherwise. Stop, protect the area and contact a supervisor.

Power tools and extension cords must be _______ each time they are used

Inspected

Fuses and Circuit Breakers

Intended primarily for the protection of conductors and equipment

If a power tool or extension cord is worn or has broken insulation ....

It must be taken out of service immediately.

Low voltage does NOT mean ...

Low hazard

Arc-Blast

Luminous electrical discharge that occurs when high voltages exist across a gap between conductors sending current through the air.

Electrical burns

Occur when a person touches electrical wiring or equipment that is used or maintained improperly.

Insulation

Plastic or rubber coverings that do not conduct electricity. Prevents live wires from coming in contact with people.

The longer the exposure to electrical shock ....

The increased danger of shock to the victim.

Don't cause _______ hazards or create _______ points for cords.

Tripping hazards or create pinch points

Falls

Workers in elevated locations who experience a shock may fall, resulting in serious injury or death.