Transcript Electrical Safety

Basic Electrical Safety
Objectives
 Basics of Electricity
 Conductors and Insulators
 “Play It Safe, It’s The Law”
Objectives
 Not designed to qualify you to work on electrical
systems
 Not designed to be inclusive of all regulations
regarding working near electrical lines/facilities
 As a reminder, if you identify problems with electrical
systems, please report them immediately
Basics
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Electricity flows in a completed path or loop
Electricity will not flow until there is a complete loop
Electricity will take the easiest and all paths to ground
Electricity flows through conductors such as metal or
water
 Because the human body is mostly water, it is a
conductor of electricity
Basics
 Electricity is measured in different ways
 Volts
 Amperes (Amps)
 Watts
 Volts measure the “pressure” under which electricity flows.
 Amps measure the amount of electric current.
 Watts measure the amount of work done by a certain amount of
current at a certain pressure or voltage.
 To understand how they are related, think of water in a hose.
Turning on the faucet supplies the force, which is like the
voltage. The amount of water moving through the hose is like
the amperage. You would use lots of water that comes out
really hard (like a lot of watts) to wash off a muddy car. You
would use less water that comes out more slowly (like less
watts) to fill a glass.
Effect on the Human Body
 Shock
 Burns
 Electrocution
Have you ever been shocked?
 More than 3 ma painful shock
 More than 10 ma muscle contraction “no-let-go”
danger
 More than 30 ma lung paralysis- usually temporary
 More than 50 ma possible ventricular fibrillation (heart
dysfunction, usually fatal)
 100 ma to 4 amps certain ventricular fibrillation, fatal
 Over 4 amps heart paralysis; severe burns. Usually
caused by >600 volts
OSHA and State Plans
 The following states have approved State Plans:
 Alaska, Arizona, California, Connecticut, Hawaii,
Indiana, Iowa, Kentucky, Maryland, Michigan,
Minnesota, Nevada, New Jersey, New Mexico, New
York, North Carolina, Oregon, Puerto Rico, South
Carolina, Tennessee, Utah, Vermont, Virgin Islands,
Virginia, Washington, and Wyoming
 NOTE: The Connecticut, New Jersey, New York and
Virgin Islands plans cover public sector (State & local
government) employment only.
The Law
 Chapter 752 of the Texas Health & Safety Code makes
it unlawful for unauthorized persons to:
 move to, or place any objects, within six feet of any
high voltage overhead electric line (over 600 volts),
or
 to operate certain machinery or equipment within
six feet of any high voltage overhead electric line
 Chapter 752 also requires unauthorized persons to
contact the owner of the lines 48 hours before work
within these zones is started
Low Voltage Power Lines
 Low Voltage is 600 volts or less
 Residential structures will be fed by single phase
lines from a transformer
 Commercial structures will be fed by three phase
lines from a transformer
 The minimum approach distance for low voltage lines
is 3 feet for insulated lines
 The minimum approach distance for low voltage lines
is 10 fee for uninsultated lines
Know Before You Dig
 Electric cables can also be buried underground
 Under streets
 Under alleys
 Buried in residential yards
 Call before you dig 1-800-DIG TESS (344-8377)
Items to Consider
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Scaffolding
Extension ladders
Metal poles
Trenching machines
Shovels
Tools
Do and Do Not
 Do plug power equipment into wall receptacles with
power switches in the “Off” position.
 Do unplug electrical equipment by grasping the plug
and pulling. Do not pull or jerk the cord to unplug the
equipment.
 Do not drape power cords over hot pipes, radiators or
sharp objects.
 Do check the receptacle for missing or damaged
parts.
 Do not plug equipment into defective receptacles.
 Do check for frayed, cracked, or exposed wiring on
equipment cords.
Do and Do Not
 Do check for defective cords clamps at locations
where the power cord enters the equipment or the
attachment plug.
 Do not use extension cords in office areas.
 Do not use “cheater” plugs, extension cords with
junction box receptacle ends.
 Do know the location of electrical circuit breaker
panels that control equipment and lighting in their
respective areas. Circuits and equipment disconnects
must be identified.
Questions?
Jeff O’Connor
TXU Electric Delivery
Safety Coordinator
500 N Akard
LP 11041
Dallas, TX 75201