Grounding - hdbk109220040100

DOE-HDBK-1092-2004

Figure 6-1(b). Second disconnect not required. A monorail hoist does not require a

disconnecting means in the leads to the hoist machinery if it is controlled from the

floor, if it is within view of the power supply disconnect, and if there is no work

platform provided to service the hoist machinery.

6.2.3

GROUNDING

NEC grounding requirements consider the crane or hoist with all its associated equipment,

including electrical equipment, as a single piece of equipment; therefore, all the conductive

component parts shall be bonded together so that the entire crane or hoist is grounded in

compliance with NEC Article 250, and NEC Article 610. Metal-to-metal contact is required

between all surfaces including the trolley wheels and bridge. If any such surfaces are painted or

otherwise insulated, a separate bonding conductor is required.

The bonding of all conductive surfaces by metal-to-metal contact is not to be considered as the

equipment grounding conductor for the electrical equipment (motors, motor controllers, lighting

fixtures, transformers, etc.)on the crane or hoist. The equipment ground conductors that are run

with the circuit conductors shall comply with NEC Article 250.

6.2.4

CONTROL

A limit switch is required to prevent the load block from passing the safe upper travel limit on all

hoisting mechanisms.

6-4