Working on an aerial lift near power lines can be risky. Getting shocked from a live power line is a common, and sometimes deadly, hazard. In fact, it is a leading cause of fatal accidents for aerial lift workers. Deaths rarely involve electricians working on power lines. More often they happen when workers are doing maintenance, working construction, trimming trees, and other tasks.
Many types of aerial lifts are used when working on power lines. Scissor lifts are often used because they tend to be more stable. Telescopic booms tend to be used when working heights exceed 50 to 60 feet. Because they can extend out as well as up, they are often used when working on and around electrical systems. No matter what type of lift is used, power line hazards must receive workers’ full attention.
Electrical accidents occur for many reasons. The most common include:
- ✓ Failure to maintain a safe distance from the power lines
- ✓ Moving the boom in the wrong direction
- ✓ Not knowing the cable voltage
- ✓ Lack of training and certification of lift operators
- ✓ Not following power line hazard safety guidelines
The #1 Job Site Hazard Involving Power Lines
The biggest risk is a worker or the lift making contact with a live cable. The best way to avoid this type of accident is to turn off the power before starting work. Yet, this may not always be possible. There may not be a qualified person on-site to shut off the power. Or, the power utility may refuse to shut down the line if it would cut off the public energy supply.
When live power lines can’t be shut down, safety procedures should include:
- ✓ Shielding the cables
- ✓ Using insulated aerial lifts designed to work near cables
- ✓ Keeping a safe distance by using power line proximity indicators
- ✓ Not allowing the boom to get too close to the cables
More Electrical Hazards
Making contact is not the only risk when working with live power lines. Others include:
- ✓ Not wearing personal protection gear. When working on or near live cables, lift workers should wear insulated clothing and gear at all times.
- ✓ Setting up the lift on unstable ground. This is one of the worst aerial lift hazards. It can lead to tip-overs of the lift, which can cause accidental contact with the power line. Working in high winds can also lead to tip-overs.
- ✓ Electricity jumps. Electricity can “jump” through the air. When this occurs, 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)
- ✓ Using 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 and goes up with the voltage of the cable. Always determine the correct MSAD before starting the job.
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
If work conditions make it hard to keep the correct MSAD, stop work. Then inform the safety consultant. The utility firm may need to de-energize the power lines before workers can get back on the job. If not, 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
An expert from the utility firm should identify the following:
- ✓ Which cables are live
- ✓ The voltage of all live cables
- ✓ The correct MSAD based on the voltage
- ✓ Any extra measures needed to work safely
Power Line Safety On the Job
- ✓ Lift workers should be aware of all live electrical equipment in the area. This includes overhead cables because they are rarely insulated.
- ✓ Inspect the worksite before starting the job. Look for any live cables that could put workers at risk. Then place warning signs to point out any hazards.
- ✓ When setting up aerial lifts, tools and devices that can conduct electricity should not 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. Use a “spotter” to ensure that clearance between the lift and the cables does not breach the MSAD.
- ✓ Never extend an aerial lift above live cables.
- ✓ When doing electric welding work, do not use any part of the lift as an electrical ground.
- ✓ Train all lift workers how to safely work around the electrical hazards on the job site.
Aerial lifts provide a safe way to work at height when safety measures are 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.
Aerial Lift Safety Training and Certification
All lift workers should be trained and certified when working around power lines. It is required by OSHA, and can save the lives of employees. AerialLiftCertification.com (ALC) provides fast, affordable training for aerial and scissor lifts. Our online safety courses teach lift workers how to:
- ✓ Inspect the work area for live power lines
- ✓ Avoid live wires and other electrical hazards
- ✓ Correctly use rubber sole boots, insulated gloves, fall protection, and other safety gear
You may be surprised to learn our courses are quicker, easier and more affordable than you think. They can be taken anywhere you have an Internet connection. They can be completed in about an hour. And workers can print their certification cards as soon as they complete the course.
Protect your employees and your business with OSHA-approved aerial lift training from FLC!