Working on an aerial lift near power lines is a risky business. In fact, electric shocks are a leading cause of fatal accidents for aerial lift workers. They occur when the boom or operator makes contact with or gets too close to overhead cables. Deaths rarely involve electricians working on power lines. They mostly happen when workers are doing maintenance, working construction, are trimming trees and other tasks.
Accidents involving power lines occur for many reasons. The most common include:
-Not maintaining a safe distance from the power lines
-Accidentally moving the boom in the wrong direction
-Not knowing the cable voltage
-Lack of training and certification of lift operators
-Not following established safety procedures
The Risks of Working Near Power Lines
According to OSHA, anyone operating an aerial lift should be trained and certified. This is especially true when working around live power lines.
The biggest risk involves making contact with a live cable. The best way to prevent getting shocked is to turn off power to the cables before starting work. However, this may not be possible if shutting off the power would cut off the public energy supply. If live cables are the working conditions, safety procedures should include:
-Shielding the cables
-Using insulated aerial lifts designed to work near electrical hazards
-Keeping a safe distance by using power line proximity indicators
-Making precise, controlled movements of the boom to avoid getting too close to the cables
Another big risk is that electricity can “jump” through the air. When this occurs, aerial lift operators can get shocked without touching the cable. The higher the voltage in the cable, the further electricity can jump. Moist air can also increase the jump distance. Protecting against these non-contact shocks includes:
-Using the Minimum Safe Approach Distance (MSAD)
-Providing extra supervision when working around live power cables
-Having an emergency plan in case of an accident
MSAD is the minimum distance lift workers should keep between themselves and live power lines. It starts at 10 feet of clearance between the aerial lift and the cables. MSAD increases when the voltage of the power lines does, too:
Voltage MSAD (in ft.)
0 – 50,000 10
50,000 – 75,000 11
>75,000 – 125,000 13
>125,000 – 175,000 15
>175,000 – 250,000 17
>250,000 – 370,000 21
>370,000 – 550,000 27
>550,000 – 1,000,000 42
Safety Procedures On the Job
Determine the correct MSAD and use these safety measures during the setup and when operating the aerial lift.
-Lift operators should be aware of all live electrical equipment in the area. This is important with overhead power lines because they are rarely insulated.
-Managers should conduct daily visual surveys of the worksite. They should place warning signs to point out any hazards. They should also train lift operators how to safely work around the electrical hazards on the job site.
-When setting up aerial lifts, make sure tools and devices that can conduct electricity don’t enter the MSAD zone or contact power lines.
-Setting up or moving aerial lifts around overhead power lines can increase the chances of an accident. A “spotter” on the ground should ensure that clearance between the lift and power lines does not breach the MSAD.
-Never extend an aerial lift above live power lines.
-When doing electric welding work, do not use any part of the aerial lift as an electrical ground.
Some work conditions make it impossible to keep the correct MSAD. When this occurs, stop work. You must notify the Production Safety Consultant. The utility company may need to de-energize or remove the power lines before workers can get back to do the job. If that isn’t feasible, it may be possible to insulate the cables.
When to Use the 30- and 50-Foot Rules
Working on an aerial lift closer than the following distances is allowed. Note that extra safety precautions must be taken.
-30 ft. and a fully extended boom from cables on wooden poles
-50 ft. and a fully extended boom from an electrical pylon
A power line expert from the utility company should identify the following:
-Which cables carry electricity
-The voltage of all live cables
-The correct MSAD based on the voltage
-Any extra measures needed to work safely
Aerial lifts provide a safe way to work at height – but only when safety measures are properly used. When working around power lines:
-Always assume all overhead wires are live and carry a lethal voltage.
-Never assume a wire is safe to touch, even if appears to be insulated.
-Stay at least 10 feet away from overhead wires during cleanup.
-Never touch a downed overhead power line.
All aerial lift operators should be trained and certified when working around power lines. Don’t put off this training. It can be lifesaving and is important for the safety of your employees. You may be surprised to learn it is quicker, easier and more affordable than you think!