Crane and Hosts

DOE-HDBK-1092-98

ANSI and CMAA standards should be carefully reviewed to ensure that all applicable safety

requirements are covered in the specifications.

The designer should specify the following requirements:

Available system voltage

2. Control voltage

3. The motor is constructed for the specific application

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 Section 668-32.

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.

See Appendix D, Reference Matrix.

6-3