EWP Setup Near an Overhead Line
You are setting up a trailer-mounted elevating work platform (EWP) with a maximum platform height of 12 m and a working height of 14 m to replace a light fitting on a warehouse wall. The ground is a concrete apron, level and firm. The wall runs parallel to a 22 kV overhead line; the line is 4.2 m from the wall at the point of work and 8.5 m above ground. The EWP's outriggers need 3.2 m spread. A parked delivery van occupies part of the apron, so the EWP must be set up 1.8 m closer to the line than planned, putting the platform's closest approach to the line at about 2.5 m horizontally when the boom is extended toward the wall. The light fitting is at 11 m. It is a still, dry morning.
1. Evaluate the clearance to the overhead line and decide whether the setup is acceptable.
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The setup is not acceptable as described. With the EWP repositioned, the platform's closest approach to the 22 kV line is about 2.5 m horizontally. For high-voltage lines, the required exclusion zone is well beyond that - typically several metres depending on voltage and jurisdiction, and the operator and any conductive parts must stay outside it. The line is also only 8.5 m above ground while the platform can reach 14 m working height, so vertical clearance is also a concern if the boom is raised near the line. The correct judgement is to stop and not set up there. Options: move the delivery van so the EWP can be set up at the planned distance, request the line be isolated or fitted with tiger tails, use a spotter and barriers to enforce the exclusion zone, or reschedule the work. Do not rely on "it's dry" - voltage can arc, and weather can change.
2. What controls would you put in place if the line could not be isolated?
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If isolation is impossible, apply a hierarchy of controls. First, eliminate or substitute: move the work so the platform never enters the exclusion zone - relocate the EWP to the planned position by clearing the van, or use a different access method. Second, engineer: fit insulated line covers (tiger tails) and use a non-conductive boom where rated. Third, administrative: establish a marked exclusion zone on the ground with barriers and signage, brief all workers, and use a dedicated spotter whose only job is to watch the boom-to-line distance. Fourth, PPE is the last line and does not protect against high voltage. Also check the EWP's insulation rating - a standard EWP is not insulated for live-line work. Record the risk assessment and get supervisor sign-off before starting.