OSHA Safety and Health Regulations for Construction (29 CFR Part 1926) 1926.1408: 1926.1408 Power line safety (up to 350 kV), equipment operations

Before operations start, the employer must set the work zone, either by marking boundaries (flags or a range limit or range control warning device) and forbidding operation past them, or by treating the zone as a full 360 degrees around the equipment out to its maximum working radius. It must then decide whether the equipment, load line or load could get nearer than 20 feet to any power line anywhere in that zone. If so, it chooses Option 1 (utility confirms the line is deenergized and visibly grounded at the site), Option 2 (keep 20 feet away with the encroachment measures) or Option 3 (determine voltage and hold the Table A distance with those measures). Encroachment measures: a planning meeting bringing together the operator and others working near the equipment or load about line locations and prevention steps; nonconductive tag lines; an elevated warning line, a barricade or a row of signs with high-visibility markings in the operator's view, set at 20 feet (Option 2) or the Table A distance (Option 3), with a dedicated spotter plus one other measure if the operator cannot see it; and at least one of a proximity alarm, a dedicated spotter meeting the visual aid, positioning, communication and timely information criteria, an automatic warning device, an automatic range limiting device, or an insulating link/device fitted between the load and the load line's end. The one-of-five measure does not apply to Subpart V work. Utilities must supply requested voltage data within two working days. Nothing may be below a power line unless the utility has deenergized and visibly grounded it, except for Subpart V work, equipment whose highest point with the boom at true vertical (fully extended if articulating or extensible) stays more than 20 feet or the Table A distance below the line's plane, or where compliance is infeasible and 1926.1410 is met. Lines are presumed energized. Near transmitter or communication towers where charge could be induced, the transmitter is deenergized or the equipment is grounded and tag lines are nonconductive. Training: every operator and crew member working with the equipment is trained on what to do after power line contact (danger of touching equipment and ground together, staying in the cab unless fire, explosion or another emergency forces exit, the safest way to evacuate, step potential, crew keeping away from equipment and load, safe clearances), that lines are presumed energized and uninsulated unless confirmed otherwise by the utility or a qualified registered engineer, the limits of insulating links, proximity alarms and range control devices, and grounding procedures and their limits. Dedicated spotters are trained for their task, and training follows 1926.1430(g). Safety devices and aids used for compliance must meet the maker's conditions of use. Table A minimum clearances: up to 50 kV, 10 feet; over 50 to 200 kV, 15 feet; over 200 to 350 kV, 20 feet; over 350 to 500 kV, 25 feet; over 500 to 750 kV, 35 feet; over 750 to 1,000 kV, 45 feet; over 1,000 kV, as set by the utility or a qualified registered professional engineer. The upper value in each band is inclusive.