Cranes & Hoists

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andrew grant

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Sorry if this is a not the brightest question but I want confirmation and/or correction.

Article 610 appears to deal with the crane or hoist system itself, not so much with the circuit that will supply power. Even the sections that mention 'Branch-Circuit" seem to be discussing components within the system.

In the past, I have treated these type systems as "skids", meaning as a combination of motor and non-motor loads that comes pre-wired from a vendor. The vendor dictates the power level required and I supply it sizing the breaker and conductors per 430-24, etc.

Is this a correct procedure or is there something in Article 610 I should be using instead?

Thanks.
 
Re: Cranes & Hoists

Thanks, Charlie.

So, you are saying that it is appropriate to size the external circuit conductors & protection, that supply power to the entire assembly, based on Article 430, not anything in Article 610. I don't need to use Table 610-14(A)or anything else, because those sections are for the internal components of the assembly, not the power supply circuit.

Is this a correct conclusion or is there more?
 
Re: Cranes & Hoists

My opinion is that the external feed to the "crane system" should be designed to handle the load that the manufacturer declares on the nameplate that is required by 610.14(G). I agree with you, that 610.14(A) applies to components internal to the crane system.
 
I am currently looking into installing a second crane in our warehouse and read Article 610 differently.

610.31 sizes the disconnect between the contact conductors (hot-rails) and the power supply for a value not less than that calculated in 610.14(E) and 610.14(F).

610.41(A) sizes the overcurrent protection to be less than the largest branch circuit protection device plus the nameplate date from 610.14(G), corrected for demand factors.

Both of these deal with the supply of the contact conductors, not the wiring of the cranes, but of the building. The contact conductors are also sized from table 610.14(A) and shown as insulated copper. Since they are insulated, this is the wiring back to the distribution panel at the source.

I would appreciate others views on this.

One question I have is that in calculating the overcurrent protection per 610.14(A) they mention the largest branch circuit protection device plus the nameplates. The nameplates include other loads on the cranes besides the motors and 610.21(H) prevents other loads from being connected to the circuit besides the cranes, so what do they mean by the largest branch circuit?
 
I haven't had occasion to look at Article 610 since I posted my last comment on this thread, THREE YEARS AGO!

I don't suppose you considered opening a new thread, instead of dredging up an ancient one?
 
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