Power Line Clearance
Now, before assembly or disassembly of a crane, the employer must determine if it could come within 20 feet of a power line. If so, the employer must either confirm with the power company that the line is de-energized and visibly grounded at the worksite, make sure no part gets within 20 feet of the power line or follow the requirements of Table A, which has minimum distances based on voltage.
If the line is not de-energized (which is usually the case), the employee is required to conduct a meeting with the assembly/disassembly crew to review measures to prevent encroachment; they must use only nonconductive tag lines; and they must use a dedicated spotter, an elevated warning line/barrier in view of the operator, or an alarm/ automatic control system.
Cranes cannot be assembled or disassembled below an energized power line or within the minimum distances referenced in Table A of a power line. And if Table A is used, the owner/utility must provide the voltage to the employer within 2 days of a request. Power lines must be assumed to be energized until they are confirmed to be de-energized and visibly grounded. Warnings about electrocution hazards must be posted in the view of the operator in the cab and outside the cab.
The work zones around equipment must be marked 360 degrees around the equipment to prevent encroachment within 20 feet of a power line. If the line is not de-energized, a meeting must also be held with the crew before operations begin to review the location of the lines and procedures to prevent encroachment.
Operators and crew members must now be trained on the procedures to follow in the event of a contact; that power lines must be presumed to be energized until confirmed and visibly grounded, that power lines are presumed un-insulated until otherwise confirmed by the owner or a qualified person, on the limits of insulating links and other devices, and on proper grounding procedures and their limitations. Spotters must also get training as applicable to their work and responsibilities.
The minimum clearance distances are specified in Table A as:
|Voltage (kV)||Minimum Clearance Distance (ft)|
|Up to 50||10|
|>50 to 200||15|
|>200 to 350||20|
|>350 to 500||25*|
|>500 to 750||35*|
|>750 to 1,000||45*|
|>1,000||determined by the utility/owner|
* According to 1926.1409, for power lines over 350 to 1,000 kV, the minimum distance is presumed to be 50 feet. Over 1,000 kV, the utility/owner or a registered engineer must establish the minimum distance.
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