Understanding Electrical Safety When Using Aerial Work Platforms

Aerial work platforms are systems that enable workers to access high elevations where it might be unsafe or difficult to work from a ground level platform. They have many applications in electrical maintenance, construction, facility work, telecommunications and infrastructure projects. But if they're used in proximity to energized electrical equipment or over energized power lines, even a small error can result in a serious electrical hazard.

This is why it's essential to grasp how electricity behaves with the aerial equipment when working at height. The risk of electrical contact can be greatly minimized through careful planning, selection of equipment, clearance distances and operator awareness.

Electrical hazards are very important to consider when working on Aerial Work Platforms

The greatest electrical hazard is that of accidental contact with a live conductor. An Aerial Platform may bring a worker, boom, basket or other conductive component closer to the power lines than a worker might think.

In some cases electricity can flow through conductive equipment without touching. This does not imply that keeping a small gap visible is always adequate. Prior to starting work, the electrical system voltage, equipment movement, environment, and applicable safety requirements must be considered.

The risk is especially significant if the platform is being repositioned or extended, as the boom is able to extend up and down and side to side over a wide range of operations.

Check for Electrical Hazards prior to Platform Raising

An appropriate worksite evaluation should be conducted prior to placing an aerial platform.

Workers should identify:

Over power lines and electrical conductors.
Transformers and other energized equipment that is not an electric power source.
The electrical system voltage level of nearby electrical systems
The intended movement of the boom and platform.
Contact points that may occur when setting up and operating the equipment.
Soil composition near the equipment

Not all hazards can be detected during a visual inspection. Electrical facilities can be hard to identify, particularly in and around buildings, industrial sites and busy work areas.

The best way to do this is to know the equipment's total operating envelope prior to lifting the platform.

Maintain Appropriate Clearance From Power Lines

One of the primary electrical safety precautions for aerial-platform activities is good clearance from energized conductors.

This distance will vary on the system voltage, local regulations, the type of activity being performed and the equipment used. Workers should therefore adhere to the appropriate electrical and occupational safety standards instead of using a general rule of distance.

The clearance must be greater than the worker's body configuration. As equipment moves during this process, all parts of the platform, including the boom, basket, tools, materials and more, can enter the hazard zone.

During operation, the separation distance may be decreased by the unexpected motion of the power lines or the platform caused by wind.

Take into account Grounding and Equipment Condition

However, with electrical hazards, one of the key factors to consider is grounding. Electrical and mechanical components in aerial platforms need to be maintained in accordance with the manufacturers' specifications and the applicable safety standards.

Pre-use safety checks should include checking for damaged or exposed cables, broken conductors, malfunctioning controls, or other issues that may pose an electrical hazard.

Grounding is NOT a means of safe separation from energized conductors, however. It is still important to have adequate clearance and hazard control.

Don't be afraid to use the proper platform for the appropriate task

The choice of equipment may affect electrical safety. Aerial platforms come in a variety of different configurations, working heights, reach and operating characteristics.

In cases where work is to be done at a considerable height, a truck equipped with boom lift configuration might have the reach and mobility required to accomplish the job. But, choosing a piece of equipment because of its maximum working height alone does not suffice. Other factors that operators should take into account are the platform's reach, load capacity, terrain requirements and electrical hazards around the work area.

The equipment should be suitable to the job and not just the biggest and tallest.

Make sure to manage the Work Area.

A work zone that has been controlled can help keep people or equipment unintentionally in an electrical hazard area.

Employers may use (where appropriate):

Warning signs
Physical barriers
Spotters
Clearly defined exclusion zones
Pre-job safety briefings
Workers and communication procedures between workers

A spotter is especially beneficial when it is difficult for the operator to view overhead conductors or the surrounding area. A spotter should not, however, be used to substitute for the necessary safety procedures or electrical clearances.

When does the Platform Touch a Power Line?

When an Aerial Work Platform comes in contact with an energized power line, it can become very unsafe. The equipment can be energized, and a person can touch the equipment and the ground or another conductive object, providing a path for current to flow through the person.

Employees should adhere to the Emergency procedure and should not handle the equipment until it has been declared safe by a qualified person. Ground personnel should also not approach the machine as there may be electrical hazards.

Before work starts, make sure that procedures are in place for emergencies in case someone is accidentally contacted.

Training an operator is a must

Operators' awareness is a key element in electrical safety. The worker(s) should be familiar with the work equipment being used, understand electrical risks and be aware of workplace procedures.

Equipment inspection, safe positioning, operating limits, emergency procedure and hazards of overhead electrical systems should be addressed during training.

Operators should also check the planned movement of the platform prior to work. When the machine is in operation, consider all the movements that it might make and see if hazards can be found that would not be apparent when the machine is parked.

Final Thoughts

While useful for maintenance, construction and infrastructure work, aerial work platforms need to be planned carefully when used in the vicinity of electrical systems. Some of the key components of electrical safety include hazard identification, necessary clearance, selection of appropriate equipment, platform inspection and clear emergency response procedures.

The basic rule has been highlighted - never assume that an overhead electrical conductor is safe, just because no one is touching it. Consider energized equipment in the vicinity a serious hazard; adhere to all applicable safety requirements; perform electrical hazard assessments as part of all aerial-platform operations.

Article by: Jack Dawson