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Low Voltage Trailing Cables

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OhioAviator

Electrical
Sep 8, 2003
123
Hello all, thanks in advance for your advice. Here's the situation....

We are making preparations to erect a new semi-mobile crane that will run on railroad tracks, not at all unlike cranes used on wharves. This one will be used to load large scrap metal pieces into a hydraulic shear for cutting up and processing.

The operating voltage of the crane will be 480Vac, 3-phase, 60Hz and will be supplied via a trailing cable. The crane will incorporate a cable reel to keep the excess trailing cable reeled up at all times.

Question:
According to the NEC, does this crane require a resistance grounded system and/or some sort of grounding conductor integrity monitor to continuously monitor the integrity of the grounding conductor in the trailing cable?

I can find references in the NEC for this sort of system for equipment operating at more than 1,000 volts.
(Ref. Art. 250.20 (C) & Art. 250.188). However, I can find no NEC requirement for this type of system for mobile equipment operating below 1,000 volts.

Thanks!


 
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