The safe maintenance or repair of any electrical apparatus requires a thorough knowledge of engineering, safety, and repair techniques, and personnel should be familiar with the particular features of the apparatus involved. Only qualified workers should do such work and these workers should refer to the manufacturer's testing procedures, warnings, and instructions on how to service such equipment.

2.13.1 TRAINING

Qualified workers shall be knowledgeable and trained in safety-related work practices, safety procedures, and other requirements that pertain to their respective job assignments. Employees shall not be permitted to work in an area where they are likely to encounter an electrical hazard unless they have been trained to recognize and avoid these hazards. (See Section 2.8.)

2.13.1.1 LIVE PARTS

Live parts that an employee may be exposed to shall be deenergized before the employee works on or near them, unless it can be demonstrated that deenergizing introduces additional or increased hazards or is infeasible because of equipment design or operational limitations. (See Section 2.1.1.) Examples of infeasibility because of equipment design or operational limitations are as follows:

1. Tests

2. Adjustments

3. Troubleshooting

4. Interruption of life supports

5. Removal of lighting in an area

6. Deactivation of alarm systems

7. Shutdown of ventilation in hazardous locations

8. Shutdown of a process or system creating a greater hazard.

Live parts that operate at less than 50 volts to ground need not be deenergized if there will be no increased exposure to electricalburns or to explosion due to electrical arcs [See 29 CFR 1910.333(a)(1)].

2.13.1.2 SAFE PROCEDURE

Safe procedures for deenergizing circuits and equipment shall be determined before circuits or equipment are deenergized. The deenergization procedures shall be included in the lockout/tagout procedure for the circuit or equipment to be deenergized.

2.13.1.3 CIRCUITS AND EQUIPMENT

Circuits and equipment to be worked on shall be disconnected from all electric energy sources. Control circuit devices such as push-buttons, selector switches, and interlocks shall not be used as the sole means for deenergizing circuits or equipment per 29 CFR 1910.147(b) and 1910.333(b)(2).

2.13.1.4 STORED ELECTRICAL ENERGY

Stored electrical energy that might endanger personnel shall be placed in a safe state. Capacitors shall be discharged and high-capacitance elements shall be short-circuited and grounded if the stored electrical energy could endanger personnel per 29 CFR 1910.147(d)(5) and 1910.333(b)(2).

2.13.1.5 STORED NONELECTRICAL ENERGY

Stored nonelectrical energy in devices that could reenergize electric circuit parts shall be blocked or relieved to the extent that the circuit parts could not be accidentally energized by the device per 29 CFR 1910.147(d)(5). For example, such specific devices are wound springs and pneumatic-driven devices.

2.13.1.6 LOCKOUT/TAGOUT PROCEDURE

Each employer shall document and implement lockout/tagout procedures to safeguard employees from injury while they are working on or near deenergized electric circuits and equipment. The lockout/tagout procedures shall meet the requirements of 29 CFR 1910.147(c) to (f), 1910.269(d) and (m), 1910.333, and 1926.417. (See Figure 2-6.)

2.13.2 VERIFICATION OF DEENERGIZED CONDITION

Verification shall be made that all live circuits, parts, and other sources of electrical energy, including any mechanical energy, have been disconnected, released, or restrained.

A qualified worker shall operate the equipment operating controls, perform voltage verification, inspect open switches and draw-out breakers etc. to assure the isolation of energy sources.