20/05/2022

HSSE WORLD

Health, Safety, Security and Environment

Photo of the day: Overhead Power lines Clearance

8 min read

Overhead power lines cause 40% of all electrically related fatalities, in the workplace. A majority of these accidents occur with workers that have little to no electrical safety training. That’s why it’s important to always look up before doing any kind of work on a construction site. It could save your life. 

If the equipment operator had raised the bed into the power line, both the line and the truck would be considered live and dangerous. If you see the equipment in contact with a power line, it’s not time to be a hero, you need to stay away and warn others to do the same.

You should stay at least 35 feet back. That’s about two dump truck lengths. If conditions are wet, you may need to move away even further.

The Photo of today outlines the clearance and safe distance from overhead Power lines So when you are on the job site remember to ALWAYS LOOKUP. ALWAYS. It could save your life and the lives of those around you.

Overhead Powerline

Power Lines Safety

let’s have an example of the Assembly or disassembly of a crane near Overhead powerlines

Before assembly or disassembly of a crane, the employer must determine if it could come within 20 feet of a power line (up to 350 kV). If so, the employer must take one of the following actions:

  • (a) Confirm with the power company that the line is de-energized and visibly grounded at the worksite.
  • (b) Make sure no part gets within 20 feet of the power line.
  • (c) Follow Table A, which has minimum clearance distances based on voltage.

Table A: Minimum Clearance Distances Based on Voltage

VoltageLimited Approach Boundary
< 50 V10 ft (3 m)
50 V – 150 V
151 V – 750 V
751 V -15 kV
15.1 kV – 36 kV
36.1 kV – 46 kV
46.1 kV – 72.5 kV10 ft (3 m)
72.6 kV – 121 kV10 ft 8 in (3.3 m)
138 kV – 145 kV11 ft (3.4 m)
161 kV – 169 kV11 ft 8 in (3.6 m)
230 kV – 242 kV13 ft (4 m)
345 kV – 362 kV15 ft 4 in (4.7 m)
500 kV – 550 kV19 ft (5.8 m)
765 kV – 800 kV23 ft 9 in (7.2 m)
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 it.

Learn more: High-Voltage Electrical Safety(Opens in a new browser tab)

Cranes cannot be assembled/disassembled below an energized power line or within the Table A clearances from a power line. If Table A is used, the owner/utility must provide the power line voltage to the employer within two days of a request.

Common Power distribution lines

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 conspicuously in the crane cab and outside the cab in view of the operator (except for overhead gantry and tower cranes).

The work zones must be demarcated 360 degrees around the equipment to prevent encroachments 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. Measures similar to those required during assembly/disassembly must be taken to prevent encroachment, but in this case, an insulating link between the load line and the load is also an option.

Operators and crew members must be trained:

  • On the procedures to follow in the event of power line contact
  • To presume that power lines are energized until confirmed and visibly grounded
  • To presume that power lines are not insulated until otherwise confirmed by the owner or a qualified person
  • On the limits of insulating links and other devices (e.g. proximity alarms)
  • On proper grounding procedures and their limitations.


Spotters must also get applicable training.

What If the line is not De-Energized?

If the line is not de-energized, the employer must take the following actions:

  • Conduct a meeting with the assembly/disassembly crew to review measures to prevent encroachment.
  • Use only non-conductive tag lines.
  • Use a dedicated spotter, a proximity alarm, a range control warning device, an automatic limit device, or an elevated warning line/barrier placed in view of the crane operator.

Exceptions to Table A? Follow these minimum Precaustions

If work must operate closer than the Table A values, then the following precautions must be taken at a minimum:

  • The employer must show that Table A is infeasible and that it is infeasible to de-energize and ground or relocate the line.
  • Safe distances must be determined by the owner/operator of the line or a registered professional engineer who is a qualified person.
  • A planning meeting must be held and procedures developed must be implemented (if procedures are inadequate, work must be stopped and new procedures established or the line must be de-energized).
  • Automatic re-energizing devices must be inoperative.
  • A dedicated spotter must be assigned.
  • An elevated warning line/barricade or an insulating link must be installed between the line and the load, except for work on electrical transmission/distribution lines covered by Subpart V (additional provisions take effect one to three years after the effective date).
  • Non-conductive rigging must be used.
  • A range-of-motion limiting device must be used.
  • Non-conductive tag lines must be used.
  • Barricades at least 10 feet from the equipment (where feasible) must be established.
  • Equipment must be properly grounded.
  • Workers must be kept from touching the line above the insulating link.
  • Only essential personnel are allowed in the area.
  • Insulating line hose or cover-up must be installed by the owner/operator unless unavailable.
  • The owner and user must meet with the equipment operator and other workers to review procedures.
  • One person must be identified who will implement the plan and can stop work if necessary.
  • Documentation of these procedures must be immediately available on site.
  • Safety devices and aids must comply with manufacturers’ specifications.
  • All employees must be trained in power line safety per 1926.1408 (g).
Common Types of Power distribution lines

Equipment Clearance Distances

Equipment traveling under or near a power line must:

(a) Have a lowered boom/mast and support system
(b) Obey minimum clearance distances set in Table T
(c) Reduce speeds to minimize breaching
(d) Use a dedicated spotter if closer than 20 feet
(e) Illuminate or identify the power lines at night
(f) Identify and use a safe path of travel.

Learn more: Working safely near overhead electric power lines

TABLE: T

Minimum clearance distances while traveling with no load

Voltage (kV)Minimum clearance distance (feet)
Up to 0.75 kV4 ft
>0.75 to 50 kV6 ft
>50 to 345 kV10 ft
>345 to 750 kV16 ft
  >750 to 1,000 kV20 ft
> 1,000 kV*
>1,000Determined by the utility/owner
*Established by the owner or registered professional engineer/qualified person.

Download the photo

Now you can download the Infographic ” Overhead Power lines Clearance ” and post it at the workplace and communicate with everyone to be familiar with the safe Clearance during working under overhead power lines


Photo of the day: Overhead Powerline Clearance


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