Certain methods and steps should be exercised when placing grounds and loads to protect workers from high-voltage hazards.

7.5.2.1 DEENERGIZED LINES

When an energized line or equipment in excess of 600 V is removed from service to be worked on, it shall be treated as energized until it is deenergized, tagged, locked if necessary, tested, and grounded.

7.5.2.2 NEW CONSTRUCTION OR DISMANTLING OF FACILITIES

If isolating devices are not in place and energization is impossible from any source, single-phase grounding is appropriate, acceptable, and safe. If energization is possible by the closure of a jumper or isolating device, shorts and grounds shall be used unless conductor handling activity makes this impractical or impossible because of line design or construction process.

7.5.2.3 MINIMUM APPROACH DISTANCE FROM UNGROUNDED CONDUCTORS

The minimum approach distances in Section 2.13.4.1 shall be maintained from ungrounded conductors at the work location. (See Table 7-2 for 29 CFR 1910.269 Table R6). The ground may be omitted if the making of the ground is impractical or the resulting conditions are more hazardous than working on the lines or equipment without grounding. However, all work shall be done as if the line or equipment were energized.

7.5.2.4 VISIBLE THREE-PHASE SHORT AND GROUND REQUIRED

Visible three-phase short circuiting may be accomplished through conductive parts such as guy wires and unpainted metal tower members, but shall not be effected through a grounding mat or other concealed conductors.

7.5.2.5 GROUND CIRCUIT

No power disconnect switch, power circuit breaker, transformer, wave trap, or fuse shall be part of the protective grounding circuit.

Table 7-2. AC Live-line work minimum approach distance

Note 1: These distances take into consideration the highest switching surge an employee will be exposed to on any system with air as the insulating medium and the maximum voltage shown.

Note 2: The clear live line tool distances shall equal or exceed the values for the indicated voltage ranges.

Note 3: See 29 CFR 1910.269, Appendix B for information on how the minimum approach distances were derived.