Temporary Power Training Guide
(Taken from the "Tailgate Meetings that Work : A Guide
to Effective Construction Safety Training" series)
Robin Baker, Robert
Downey, Mary Ruth Gross, Charles Reiter
Labor Occupational Health Program
(LOHP) School of Public Health,
University of California, Berkeley Ca.
talks were developed for use under California OSHA regulations. The
complete set is available from the Labor Occupational Health Program
at UC Berkeley. For ordering information, visit the website (www.lohp.org)
The American Conference of Government Industrial Hygienists (ACGIH)
has adapted these talks to apply to federal OSHA regulations. To contact
ACGIH, visit its web site (www.acgih.org).
Before you begin
- Does this topic
relate to the work the crew is doing? If not, choose another topic.
- Did you read
this Training Guide and fill in the blanks where the
appears? (To find the information you need, look over the Safety Walkaround
Checklist for this topic.)
- (If applicable):
Did you bring a GFI (ground fault circuit interrupter) to show the crew?
- (If applicable):
Did you bring an extension cord with inspection markings?
electrical wiring on a construction site requires special caution. A minor
shock can be the shock of your life if it causes a serious burn or fall.
Sometimes a small shock can interfere with your heartbeat or even kill
Whenever we install,
repair, or change temporary wiring, a qualified electrician must do the
work or supervise it. Don't try to reroute temporary power or add new
You or a crew member
may want to add a personal story about temporary power.
Next, discuss with
the crew where temporary power is used at this particular job site:
THE CREW THESE QUESTIONS:
After each question,
give the crew time to suggest possible answers. Use the information following
each question to add points that no one mentions.
1. If wiring
is worn out or damaged, it could cause a shock or fire. To protect temporary
wiring from wear and weather, there are certain places it shouldn't be
In damp or
hot or cold areas
On sheet metal
or equipment might run over it.
or fumes that might make it deteriorate
edges or projections that could damage it
At pinch points
2. What are some
of the things we look for when we inspect temporary wiring?
- Can temporary
wiring safely carry the amount of current required?
- Is there a circuit
breaker to prevent overload?
- Are all temporary
wiring installations grounded?
- Are wiring and
equipment in safe condition and secured firmly?
- Do all conductors
have insulation? (Never use bare conductors.)
- Are switches
labeled clearly, showing what they control and which position is off?
- Do boxes and fittings
have covers or barriers to prevent contact with live parts?
- Is temporary wiring
used only for periods of less than one year (unless special state permission
- Is it removed
promptly when construction is done or when the permit time expires?
3. What is a
GFI grounding system and why is it important?
Show the crew
the GFI you brought to the meeting, and/or an extension cord with inspection
markings from the company's grounding conductor program.
- A GFI is a ground
fault circuit interrupter. It senses ground faults (accidental electrical
paths to ground) and cuts off all power in the circuit.
- For example,
if there is a short in a power tool, the metal casing can become "live."
A GFI will cut off power before you can get a serious shock.
- Most 110-120
volt temporary wiring must have GFIs unless the company has an
"assured equipment grounding conductor program." (This is a program
where the company does regular testing of the ground on plugs, outlets,
cords, and other electrical equipment. Inspection marks are placed on
equipment and records are kept.)
4. What can you
do to prevent shocks from your own tools and equipment?
- Make sure power
tools have a 3-wire cord and are grounded. (Double-insulated tools don't
need a ground.)
- Check power tools
and cords daily for cracks, exposed wire, and breaks in the insulation.
- Tag faulty
items and send them for repair.
- If a power tool
buzzes, report it immediately and have an electrician check it out.
Either the wiring or the tool itself may be defective.
- Store cords and
tools neatly in a safe place to prevent damage.
- Don't touch any
electrical equipment when the equipment is wet, you're wet, you're sweating,
or you're standing on a wet surface. Moisture lowers your resistance.
That can make your injury worse if you get a shock.
- Don't touch any
electrical equipment if you're in contact with good conductors like
metal pipes, tanks, or boilers.
5. What are some
things you should never do when you work with electrical cords?
- Never remove the
third prong (the ground prong) from a plug.
- Never force plugs
into receptacles that don't match.
- Never use an adapter
(3-prong plug to 2-hole outlet) that isn't grounded.
- Never use ordinary
extension cords. Use 3-wire cords intended for heavy duty.
- Never splice flexible
- Never overload
a power box. If the circuit breaker trips, there's usually too much
- Never unplug
them to "borrow" the outlet, and never run extra lines off the light
6. What should
always happen before an electrician begins repair work on wiring?
- Wiring and equipment
must be de-energized.
- Energy must be
dissipated from devices (like capacitors) that store it.
- Wiring and equipment
must be locked out or tagged out.
- All affected personnel
in the area must be notified.
wiring is usually low voltage (under 600 volts). What kinds of injuries
can you get from a low voltage electric shock?
fast, irregular heartbeat.
- Injuries due to
8. What should
you do if someone gets an electric shock?
- Don't touch the
person until power has been disconnected.
- Call 911.
- Give immediate
first aid or CPR if necessary, but only if you know what you're
- Calm and reassure
the injured person. Don't move them until trained help arrives.
- Notify on-site
first aid personal or a supervisor as soon as possible.
Most of the safety measures we've talked about are required by Cal/OSHA.
We have to take these precautions -- it's the law. I have a Checklist
of the Cal/OSHA regulations on temporary power. If you'd like to know
more, see me after the meeting.
(Only if applicable.)
Besides the Cal/OSHA regulations, we have some additional company rules
about temporary power.
Do you have any other concerns about temporary power? Do you see any problems
on our job? (Let the steward answer first, if there is one.)
What about other
jobs you've worked on? Have you had any experience with temporary power
that might help us work safer on this job?
OF THOSE WHO ATTENDED THIS SAFETY MEETING
Meetings That Work : Collection
Published in June, 1994 by: Labor Occupational Health Program, School
of Public Health, 2515 Channing Way, University of California, Berkeley,
CA 94720. Phone: (510) 642-5507.
Permission is granted to duplicate these materials for non-profit educational
purposes, provided that copies are not offered for sale.
This paper appears in the eLCOSH website with the permission of the author
and/or copyright holder and may not be reproduced without their consent.
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