It is on the top of the list of things not to do especially when operating lifts of any kind.
It is one reason electric repair crews have one or two men in the bucket working while 6 men watch from the ground.
Also power company trucks have fiberglass booms for insulation from the rest of the equipment and ground.
We used to test the hydraulic oil for metallic content and would have to replace it if it became too high. It would become a path to ground otherwise.