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Safety & Health
Checklist for the
Roadway Construction Industry
Electrical
Hazards
What are volts, ohms, amps,
and current?
Voltage = force or pressure that causes
electricity to flow through a conductor (wire). (Think of water held
behind a dam.)
Ohm = resistance
that impedes the flow of electricity through a conductor. (Think of
pipes; pipe size restricts water flow.)
Amp = measurement
of current — the flow of electrons — from the source of voltage through
a conductor. (Think of water moving through a pipe.)
How much electricity will hurt
me and how?
For death to occur, the body must become part of
an electrical circuit. The actual amount of damage depends on the amount
of current (amps), the pathway of electricity as it passes through the
body, and the duration of the event.
|
Estimated
Effects of AC Currents
(U.S. Standard 60 Hz) |
| 1 milliamp (mA) |
Barely perceptible |
| 16 mA |
Maximum current an average
man can grasp and let go |
| 20-30 mA |
Paralysis of respiratory muscles |
| 100 mA |
Ventricular fibrulation threshold |
| 2 Amps |
Cardiac standstill and internal organ damage |
| 15/20/30 Amps |
Common U.S. household breakers |
|
 |
Protect your
employees from electrical hazards by following this simple checklist.
Check for these common sources
of electrical energy exposure:
❑ Worn power cords (extension cords, hand
tools).
❑ Water on or near electrical outlets,
tools, and cords.
❑ Temporary circuit boxes and breakers for
construction job sites.
❑ Switches and connections on equipment,
vehicles, and machinery.
❑ Buried utilities.
❑ OVERHEAD POWER
LINES.
What are some precautions you
can take to avoid contact with electrical energy:
❑ Ensure buried utilities are marked by
proper authority.
❑ Locate and mark overhead power sources;
develop protocols for working near overhead
power lines.
❑ De-energize, lockout, and tagout power
sources for equipment, tools, and machinery
before repairing or
servicing.
❑ Use ground fault circuit interrupters on
all power tools and equipment.
❑ Inspect tools, cords, etc. to ensure it is
in good condition before each use.
❑ Use appropriate personal protective
equipment, including:
❑ Insulated gloves and footwear.
❑ Non-metallic ladders.
This material was produced under grant number 46C3-HT31 from the
Occupational Safety and Health Administration, U.S. Department of
Labor. It does not necessarily reflect the views or policies of the
U.S. Department of Labor, nor does mention of trade names,
commercial products, or organizations imply endorsement by the U.S.
Government. The developers have not assumed any part of the
employer’s exclusive responsibility to provide a safe and healthful
work place.
Reprinted from Better Roads Magazine
July 2006 |
