Assume that every line is "hot".
Appoint a reliable and qualified signal person, equipped with a loud signal
whistle or horn and voice communication equipment, to warn the operator
when any part of the crane or load moves near a power source. This person
should have no other duties while the crane is working.
Warn all personnel of danger. Allow no unnecessary personnel in the area.
Permit no one to lean against or touch the crane. Permit no one including
sling men or load handlers to hold load, lines, or rigging gear.
Even if the crane operator is not affected by an electrical contact, others in
the area may become seriously injured or killed.