The following tasks are some examples of possible exposure to energized conductors:
a) Measuring, testing, and probing electrical system components;
b) Working near battery banks;
c) Opening electrical equipment enclosure doors or removing covers;
d) Inserting or pulling fuses;
e) Drilling, or otherwise penetrating, earth, walls, or ßoors;
f) Pulling conductors in raceways, cable trays, or enclosures;
g) Lifting leads or applying jumpers in control circuits;
h) Installing or removing temporary grounds;
i) Operating switches or circuit breakers;
j) Working inside electronic and communications equipment enclosures.
Evaluating the degree of hazard
Each of the tasks mentioned above should be evaluated for the degree of electrical hazard involved. For example, opening an enclosure door of a 120 V control panel containing many relays and terminals does expose a person to an electrical hazard.
But the probability of serious injury may be small due to the lower voltage and lower fault current capacity. Whereas, opening the door or cover of an energized, 13 800 V primary disconnect switch enclosure exposes a person to a much greater danger due to the higher voltage and larger fault current capacity. Different procedures, personal protective equipment, approvals, and attendance would be required.
Actions to eliminate, minimize, or control the hazard
Obviously, it would be most desirable to eliminate any hazard. The best way to do that is to rethink the purpose of the job and why it cannot be accomplished by establishing an electrically safe work condition. If the answer is “inconvenience” or “saving a little time”, then the answer is not good enough.
First of all, it would violate the intention of the OSHA laws. Secondly, the possible consequences if something went wrong should be considered.
When it is not possible or feasible to establish an electrically safe work condition, it is extremely important that work on or near exposed energized parts be thoroughly planned and strictly controlled. Work shall be done only by qualified personnel who have been trained to use safe practices and protective equipment.
Permit for energized work
In addition to work authorization documents, it is desirable to have a special permit system to give specific permission to work on or near energized electrical conductors or circuit parts. This permit would list the following items that are required before working on or near exposed energized electrical conductors or circuit parts:
a) Justification for energized work;
b) Personal and other protective equipment;
c) Test equipment;
g) Existing procedures to use;h) Special notes.