Follow these rules to make sure your installation is compliant with the National Electrical Code (NEC).
You must provide a disconnecting means in the leads from the runway contact conductors (or other power supply) of cranes and monorail hoists [Sec. 610.32]. It must be lockable in the open position per Sec. 110.25, and comply with Sec. 430.109.
You can omit the disconnect where a monorail hoist or hand-propelled crane bridge installation meets all of the following:
- It’s controlled from the ground or floor level.
- It’s within view of the power supply disconnecting means.
- There’s no fixed work platform for unit servicing.
And at the operating station, there must be a means for opening the power circuit to all motors of the crane or monorail hoist.
The runway conductors must also have a disconnect complying with Sec. 430.109 [Sec. 610.31]. Additional requirements for this disconnect include:
- Readily accessible operable from the ground/floor.
- Lockable in open position.
- Opens all ungrounded conductors simultaneously.
- In sight from the runway contact conductors, unless that location is impractical or more hazardous, or where written safety procedures in an industrial setting ensure only qualified personnel service the equipment.