Crane and Hoists

DOE-HDBK-1092-2004

4. Motor horsepower, service factor, insulation class, and time ratings are sufficient to meet the

load requirements

5. Working clearances and space requirements

6. Disconnecting means and other NEC requirements

6.2

CRANES AND HOISTS

The most significant factor in crane and hoist safety, after structural integrity, is electrical safety.

All the referenced standards support this fact either directly or indirectly by the amount of

definition and space provided for electrical systems' controls, operations, and maintenance.

6.2.1

NEC GENERAL REQUIREMENTS

Basic installation and wiring safety requirements for cranes and hoists are given in NEC Article

6101. Electrical designers and maintenance personnel should thoroughly understand these

requirements and their intent. Some of the more significant requirements are the following:

1. Cranes and hoists operated in hazardous (classified) locations shall conform to NEC Article

500.

2. When the crane is operated above readily combustible materials, the resistors must be

located in a well-ventilated cabinet constructed of noncombustible material and constructed

so that they will not emit flames or molten metal. See the exception (and requirements) that

applies to certain cabinets made of noncombustible materials.

3. Cranes and hoists operating on electrolytic cell lines have special requirements, as given in

NEC 668.

a. Grounding is not required for conductive surfaces of cranes and hoists that enter the

working zone of a cell line, and the parts that come in contact with an energized cell or

attachments shall be insulated from ground.

b. Remote controls that may introduce hazardous conditions into the cell line working zone

shall employ one or more of the following:

(1) Isolated and ungrounded control circuit in compliance with NEC Section 668.21(a)

(2) Nonconductive rope operator

(3) Pendant pushbutton with either non-conductive support and surfaces or ungrounded

exposed surfaces.

(4) Radio

See Appendix D, Reference Matrix.

6-2