Power Line Work: Grounding and Protective Equipment

Grounding for deenergized work

• Purpose. The grounding rules apply to grounding of transmission and distribution lines and equipment to protect employees.
• The rule. For any employee to work these lines or equipment as deenergized, the employer must ensure the lines or equipment are deenergized under the standard's deenergizing provisions, and must ensure proper grounding as specified in the grounding paragraphs.

Deenergized alone is not enough. Grounding is part of what makes a line safe to work as deenergized.

Reference: 29 CFR 1926.962(a) · 29 CFR 1926.962(b)

The narrow exception

The employer may skip the ground only if the employer can demonstrate that installing a ground is impracticable, or that installing it would present greater hazards than working without grounds. Even then, the lines may be treated as deenergized only if the employer establishes all of these conditions:

• The lines and equipment are deenergized under the standard's deenergizing provisions.
• There is no possibility of contact with another energized source.
• The hazard of induced voltage is not present.

Reference: 29 CFR 1926.962(b) · 29 CFR 1926.962(b)(1) · 29 CFR 1926.962(b)(2) · 29 CFR 1926.962(b)(3)

Equipotential zone and equipment ratings

• Placement. Temporary protective grounds are placed and arranged so the employer can demonstrate they will prevent each employee from being exposed to hazardous differences in electric potential. Appendix C to the subpart has guidelines for setting up this equipotential zone.
• Fault current. Grounding equipment must be capable of conducting the maximum fault current that could flow at the point of grounding for the time necessary to clear the fault.
• Size. Grounding equipment must have an ampacity greater than or equal to that of No. 2 AWG copper.
• Impedance. Protective grounds must have an impedance low enough that they do not delay the operation of protective devices if the line is accidentally energized.

Reference: 29 CFR 1926.962(c) · 29 CFR 1926.962(d) · 29 CFR 1926.962(c) Note · 29 CFR 1926.962(d)(1)(i) · 29 CFR 1926.962(d)(1)(ii) · 29 CFR 1926.962(d)(2)

Test first, then connect in order

• Test. Unless a previously installed ground is present, employees test the lines and equipment and verify the absence of nominal voltage before installing any ground.
• Attach. Attach the ground-end connection first, then attach the other end by means of a live-line tool.
• Remove. Remove the grounding device from the line or equipment using a live-line tool before you remove the ground-end connection.

Reference: 29 CFR 1926.962(e) · 29 CFR 1926.962(f)(1) · 29 CFR 1926.962(f)(2)

Cables and temporary removal for tests

• Remote cable work. When you work on a cable at a location remote from the cable terminal, the cable is not grounded at the cable terminal if there is a possibility of hazardous transfer of potential should a fault occur.
• Temporary removal for tests. The employer may permit employees to remove grounds temporarily during tests. During the test, each employee uses insulating equipment, is isolated from any hazards involved, and any additional measures needed are implemented in case the previously grounded lines and equipment become energized.

Reference: 29 CFR 1926.962(g) · 29 CFR 1926.962(h)

When you must use fall protection

The employer must ensure employees use fall protection as follows:

• Aerial lift. Each employee working from an aerial lift uses a fall restraint system or a personal fall arrest system.
• Above 4 feet. Each employee in elevated locations more than 1.2 meters (4 feet) above the ground on poles, towers or similar structures uses a personal fall arrest system, work-positioning equipment or fall restraint system, as appropriate, if the employer has not provided other fall protection meeting subpart M.
• Climbing and changing location. Each qualified employee climbing or changing location on poles, towers or similar structures must use fall protection equipment, unless the employer can demonstrate that doing so is infeasible or creates a greater hazard than not using it.
• Trainees. Unqualified employees, including trainees, must use fall protection any time they are more than 4 feet above the ground.

The 4-foot rule and the climbing rule apply to structures that support overhead electric power transmission and distribution lines and equipment. They do not apply to portions of buildings, such as loading docks, or to electric equipment, such as transformers and capacitors.

Reference: 29 CFR 1926.954(b)(3)(iii)(A) · 29 CFR 1926.954(b)(3)(iii)(B) · 29 CFR 1926.954(b)(3)(iii)(C) · 29 CFR 1926.954(b)(3)(iii) Note 1 and Note 2 · 29 CFR 1926.954(b)(3)(iii) Note 1

Work-positioning equipment: inspect, rig, anchor

• Inspect daily. Work-positioning equipment is inspected before use each day to determine that it is in safe working condition. Equipment that is not in safe working condition may not be used.
• Free fall. Work-positioning systems are rigged so an employee can free fall no more than 0.6 meters (2 feet).
• Anchorage strength. Anchorages must support at least twice the potential impact load of an employee's fall, or 13.3 kilonewtons (3,000 pounds-force), whichever is greater.
• Snaphooks. Unless the snaphook is a locking type designed specifically for the connection, snaphooks on work-positioning equipment may not be engaged in the listed connections. One example is directly to webbing, rope or wire rope. The standard lists other connections too, so check paragraph (b)(3)(vi) before you rig.

Reference: 29 CFR 1926.954(b)(3)(i) · 29 CFR 1926.954(b)(3)(iv) · 29 CFR 1926.954(b)(3)(v) · 29 CFR 1926.954(b)(3)(vi) · 29 CFR 1926.954(b)(3)(vi)(A)