Hazardous energy control is not optional these days. It is required by law for all employees who work on de-energized equipment where there is potential for injury if the equipment is unexpectedly re-energized. This is an extremely important part of the overall electrical safety program, not only because it is the law, but also because it is a key effective method toward ensuring that employees have the electrically safe work condition.
It is often called a lockout/tagout program. OSHA regulation 29 CFR 1910.333(b)(2) states: “While any employee is exposed to contact with parts of fixed electrical equipment or circuits which have been deenergized, the circuits energizing the parts shall be locked out or tagged out or both in accordance with the requirements of this paragraph.”
That paragraph covers the following subjects:
a) Establishment and maintenance of written procedures for lockout/tagout;
b) Establishment of safe procedures for de-energizing equipment;
c) Requirements for the use of locks and tags;
d) Verification of the de-energized condition;
e) Requirements before re-energizing the circuits.
This means that a hazardous energy control program shall be established to cover all employees whose jobs could possibly expose them to energized electrical conductors or circuit parts. Hazardous energy control of electrically operated equipment is important to nonelectrical workers also.
Consider the following examples:
-Two mechanics working on a crane runway were knocked 40 ft to the floor below when a control-circuit failure caused the crane to start unexpectedly.
- A pipe fitter was scalded when an operator depressed the “open” button on a motor operated valve.
- A two-man cleanup crew was buried in a storage silo when a conveyor was started accidentally.
- A hopper gate closed on the torso of a welder who was repairing the hopper lining.
All of these accidents have a common denominator. Although none involved electricians, nor electric shock or electrocution, all were electrically initiated. Furthermore, none would have occurred if proper electrical energy control procedures had been in effect.
A hazardous energy control procedure is a part of providing an electrically safe work condition for employees. This procedure is applicable to work on electrical equipment at all voltage levels, not just for higher voltage systems.
Hazardous energy control procedures, in the electrical business, are often referred to as lockout/tagout procedures. There are several existing documents in which lockout/tagout procedures are discussed in detail. ANSI Z244.1-1982 is a document that provides good guidance for establishing lockout/tagout procedures. ANSI Z244.1-1982 has a sample lockout/ tagout procedure in its appendix.
It is quite obvious that the U.S. federal government is serious about control of hazardous energy in the workplace. OSHA regulation 29 CFR 1910.147 covers hazardous energy control in general and includes all kinds of hazardous energy, not just electrical. This document also contains a sample of a minimal lockout/tagout procedure.
OSHA regulation 29 CFR 1910.333 is speciÞcally aimed at lockout/tagout for electrical work in general industry. OSHA regulation 29 CFR 1926.417 discusses lockout and tagging of circuits for the construction industry.
OSHA regulation 29 CFR 1910.269 discusses lockout/tagout requirements for power generation, transmission, and distribution type work. Lockout/tagout practices and devices, including training, retraining, equipment, and procedures, are discussed in NFPA 70E-1995, Part II, Chapter 5.