1-14
another, and a soldering iron in still another. Also, you may be using an extension cord for some
equipments and not others or may be using other possible combinations. Some of the hazards presented
by situations such as these include contact with live terminals or test leads. In addition, cords and test
leads may be cross connected in such a manner that a potential difference exists between the metal cases
of the instruments. This potential difference may cause serious or fatal shocks.
Test leads attached to test equipment should, if possible, extend from the back of the instruments
away from the observer. If this is not possible, they should be clamped to the bench or table near the
instruments.
At times, you may use instruments at locations where vibration is present, such as near a diesel
engine. At such times, the instruments should be placed on pads of folded cloth, felt, or similar shock-
absorbing material.
WORKING ON ENERGIZED CIRCUITS
Insofar as is practical, you should NOT undertake repair work on energized circuits and equipment.
However, it could become necessary, such as when you make adjustments on operating equipment. In
such cases, obtain permission from your supervisor, then proceed with your work, but carefully observe
the following safety precautions:
DO NOT WORK ALONE.
Station an assistant near the main switch or circuit breaker so the equipment can be immediately
de-energized in case of an emergency.
Someone qualified in first aid for electrical shock should be standing by during the entire
operation.
Ensure that you have adequate lighting. You must be able to see clearly if you are to perform the
job safely and properly.
Be sure that you are insulated from ground by an approved rubber mat or layers of dry canvas
and/or wood.
Where practical, use only one hand, keeping the other either behind you or in your pocket.
If you expect voltage to exceed 150 volts, wear rubber gloves.
DO NOT work on any type of electrical apparatus when you are wearing wet clothing or if your
hands are wet.
DO NOT wear loose or flapping clothing.
The use of thin-soled shoes and shoes with metal plates or hobnails is prohibited.
Flammable articles, such as celluloid cap visors, should not be worn.
