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Electrical Safety

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Samuel Cantu

on 27 April 2016

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Transcript of Electrical Safety

An average of one worker/day is electrocuted on the job.

There are four main types of electrical injuries:
Electrocution (death)
Electrical Shock

Electrical Terminology
- Movement of electrical charge
- Opposition to current flow
- A measure of electrical force
- Substances with low resistance
- Substances with high resistance
- A protective measure of creating a conductive connection to the earth
Electrical Shock
Received when current passes through the body
Severity of the shock depends on:
Path of current through body
Amount of current through body
Length of time the body is exposed
LOW VOLTAGE does not mean low hazard
Electrical Protective Devices
Designed to shut off electricity flow in event of an overload or ground-fault
EX: Fuses, circuit breakers, and GFCI
Fuses and circuit breakers are overcurrent devices

When there is too Much Current:
Fuses Melt

Circuit Breakers Trip
Ground-Fault Circuit Interrupter
The GFCI detects a difference in current between black and white circuit wires
Occurs when electrical equipment malfunctions causing "leakage" known as a ground-fault
GFCI can shut off electricity flow in 1/40 second; protecting you from a dangerous shock
Focus on hazard identification,
avoidance, and control.

29 CFR 1910 Subpart S
Electrical Safety Video
Dangers of Electric Shock
Nominal Voltage Classifications
Low Voltage: 120V - 600V

Medium Voltage: 600V - 69 KV

High Voltage: 69 KV - 230 KV
As defined by Institute of Electrical and Electronics Engineers
Electrical Burns
Wiring Hazards
A secondary injury from an electric shock
Can lead to a serious injury; even death
Electrical Requirements
Homemade Extension Cords
Daisy Chaining Power Strips
Damaged Cords
(bad insulation)
Improper Use
(Light vs Heavy)
If too many devices are plugged into a circuit, the current will heat the wires to a very high temperature and create a risk of fire.
Currents > 75 milliamps can cause ventricular fibrillation (a rapid or ineffective heartbeat)

Will cause death in a few min if a defibrillator is not used

75 mA is not much current (small power drill can use over 2 amps)
The most common shock-related injury that is nonfatal

Occurs by contact with electrical wiring or equipment that is improperly used or maintained
Burns typically occur on the hands

Lack of adequate PPE

Serious injury that needs immediate attention
Examples of OSHA Electrical Requirements
For Protection:
3-wire cord with ground, or
Be double insulated, or
Be powered by a low-voltage isolation transformer
Path must be permanent and continuous

Electric Tools

Guarding Live Parts

Cabinets, Boxes, and Fittings

Flexible Cords
Overhead Powerlines
Train employees working with electric equipment in safe work practices, including:
De-energizing electric equipment before inspecting or making repairs (LOTO)
Using electric tools that are in good repair
Using good judgement when working near energized lines
Using appropriate protective equipment
Grounding Hazards
A commonly violated OSHA standard
If you come into contact with an improperly grounded electrical device, You will be shocked
Never use a 3-prong grounding plug with the ground prong broken off!
Hand-Held Electric Tools
Guarding Live Parts
Electric equipment operating at 50V or more must be guarded against accidental contact by:
Approved cabinets/enclosures,
Location or permanent partitions making them accessible only to qualified persons,
Elevation of 8ft or more above the working surface
Guarding Live Parts
Mark Entrances to guarded locations with conspicuous warning signs
Must enclose or guard electric equipment in locations where it would be exposed to physical damage
Cabinets, Boxes, & Fittings
Junction boxes and fittings must have approved covers
Unused openings in cabinets, boxes, and fittings must be closed (knockouts)
Use of Flexible Cords
More vulnerable than fixed wiring

Do not use if one of the recognized wiring methods can be used instead

Flexible cords can be damaged by:
Door or window edges
Staples or fastenings
Abrasion from adjacent materials
Activities in the area

Improper use of flexible cords can cause shocks, burns, or fire
Permissible uses of Flexible Cords
Pendant or Fixture Wiring
Portable lamps, tools, or appliances
Stationary equipment to facilitate interchange
Prohibited Uses of Flexible Cords
Substitute for fixed wiring
Run through walls, ceilings, floors, doors, or windows
Concealed behind or attached to building
Most people don't realize that overhead powerlines are usually not insulated

Powerline workers need special training and PPE to work safety

Do not use metal ladders (fiberglass)

Beware of powerlines when you work with ladders and scaffolding
Wet Conditions
Wet conditions are hazardous because you can become an easy path for electrical current.

There are many circumstances that create wet conditions:
Standing Water
Wet Clothing
High Humidity
As of 2015 HRC is out and ARC is in: Arc-Rated Clothing
Level 1
Level 2
Level 3
Level 4
Full transcript