Electrical, weather and environmental hazards

MEWPs take workers up into the space where power lines run, wind blows harder and lightning strikes. In IPAF's report on 2025 incidents, electrocution and electric shock were the leading cause of MEWP deaths, and most electrocution reports came from the United States, where overhead distribution lines run along streets, parking lots and building edges. Wind causes overturns that crews often do not see coming. This lesson covers these hazards and the controls that prevent them.

Overhead power lines

Electricity does not need contact to kill. At higher voltages, current can arc across an air gap to a boom, a platform or a tool held by a worker. Once the machine is energized, everyone touching it, and people on the ground near it, are at risk from touch and step potential. HSE-224 explains the electrical background; HSE-219 gives the full tables for cranes. For MEWPs, the rules are similar, and the most important control is distance.

These are minimums. The clearance must be kept between the line and the closest part of the platform, boom, workers and any conductive object they handle, allowing for sway of the line and the boom, wind, and the reach of tools. Where work must come closer, the employer must arrange with the utility to de-energize, relocate or insulate the line; only qualified electrical workers using approved methods may work closer.

Controls near power lines

• Identify every overhead line during the site assessment and find out its voltage from the utility. Do not guess from the size of the poles.
• Position the machine so that the platform cannot reach the limit of approach, if possible. A machine whose maximum reach cannot get there is the strongest control.
• Use a dedicated spotter whose only job is to watch the distance and warn the operator.
• Use barriers, flags or range-limiting devices to mark where the platform must not go.
• Never assume a line is insulated or de-energized. Covers installed by the utility reduce the risk of brief contact; they do not make a line safe to touch.
• Carry long conductive objects, such as pipes, conduit and aluminum ladders, horizontally and keep them inside the platform.

Insulated aerial devices, such as the bucket trucks used by utilities, are designed and tested for work near energized lines, but only qualified electrical workers trained in utility work methods may use them for that purpose. A standard boom lift or scissor lift has no electrical insulation, even if it has fiberglass covers or rubber tires.

If contact happens

If a MEWP contacts a power line, the people on the platform are usually safest staying where they are, not touching anything conductive, while the operator tries to move the platform away from the line if it can be done safely. People on the ground must stay well back, at least 10 m (about 33 ft), because the ground around the machine may be energized. Call the utility and emergency services. No one should approach until the utility confirms the line is de-energized and grounded. HSE-219 describes the same response for cranes, including how to jump clear if a fire forces evacuation.

Wind

Wind pushes on the platform, the workers and any material they carry. Because the force acts high above the ground, it creates a large overturning moment, and gusts arrive without warning. Outdoor-rated MEWPs are designed for winds up to a stated limit, typically 12.5 m/s (45 km/h or 28 mph). Indoor-only machines are rated for zero wind.

Three things make wind more dangerous than a forecast suggests. First, wind is stronger at height than at ground level. Second, gusts can be 30 to 50 percent stronger than the average wind speed. Third, buildings channel wind into gaps and around corners, so local wind can be much stronger than the general forecast.

Practical wind controls are simple. Check the forecast in the safe use plan, measure the wind at height with an anemometer when it is close to the limit, lower the platform when wind approaches the limit or gusts become strong, and do not carry large sheets outdoors unless the manufacturer permits it.

Lightning, cold, heat and air quality

Lightning: a raised MEWP is often the tallest object around. When thunder is heard or lightning is seen, lower the platform and move workers to shelter; a common rule is to wait 30 minutes after the last thunder before resuming.

Cold: cold reduces battery capacity, thickens hydraulic oil, makes decks and rails icy and stiffens harness webbing. Clear ice and snow from the platform and chassis; check that functions work normally before raising; dress for wind chill at height, which is colder than at ground level.

Heat: hot surfaces, sun exposure and limited shade on a platform contribute to heat stress. Plan water and breaks, and rotate workers.

Air quality: engine-powered MEWPs produce carbon monoxide and other exhaust; indoor use needs ventilation and monitoring, or an electric machine. HSE-218 covers carbon monoxide from fuel-powered equipment. Machines used in locations with flammable gases, vapors or dusts must be specifically rated for those locations.

Working near traffic and the public

Outdoor MEWP work often happens beside roads, parking lots and walkways. A vehicle striking the chassis can overturn the machine or throw the occupant out, and members of the public may walk beneath the platform. Plan traffic control as part of the safe use plan: cones, barriers or vehicle-mounted attenuators where traffic is fast, a flagger where needed, and a closed sidewalk with a safe detour for pedestrians. Work beside public roads usually needs a permit from the road authority and must follow its temporary traffic control rules.

In the United States, Part 6 of the Manual on Uniform Traffic Control Devices sets the rules for temporary traffic control, and states may add their own requirements.

Hazardous locations

Some workplaces have areas where flammable gases, vapors or combustible dusts may be present, such as fuel facilities, paint booths, grain handling and some chemical plants. A standard MEWP has electrical components and hot engine surfaces that can ignite these atmospheres. Only machines specifically built and certified for the classified location may be used there, or the area must be made safe under a hot work or equipment permit with gas testing. Check with the facility before bringing any MEWP into such an area.

Keeping watch on the weather

Weather changes during a shift. Assign someone, usually the operator or the supervisor, to check the forecast before work and to watch for changes, such as rising wind, approaching storms or freezing rain. Agree the stop criteria in advance, so that stopping is a routine decision rather than an argument at height.