Which type of personnel hoist must have an anti-piling switch installed?

A traction drum hoist requires an anti-piling switch installed as part of its safety mechanisms. The anti-piling switch is critical because it helps prevent the hoisting cables from becoming tangled or piled up, which can lead to significant operational hazards, including misalignment or failure during operation.

Traction drum hoists utilize a drum to wind and unwind the rope, and without the anti-piling switch, the risk of cable issues increases. Such challenges can not only affect the efficiency of the hoist but could also pose severe risks to personnel.

This feature ensures that the operation remains safe and prevents the potential for accidents or injuries associated with tangled hoisting cables. Thus, the requirement for an anti-piling switch is directly linked to the operational principles and safety concerns related to traction drum hoists specifically.