# Large Current Carrying Industrial Wires?



## McClary’s Electrical (Feb 21, 2009)

The NEC fpn on voltage drop is not an enforceable code. It is only a recommendation ( like all fine print notes)


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## KennyW (Aug 31, 2013)

Could you not use parallel runs?


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## Bbsound (Dec 16, 2011)

I gotta ask, wth uses 300 amps at 10 volts?


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## JRaef (Mar 23, 2009)

Bbsound said:


> I gotta ask, wth uses 300 amps at 10 volts?


Lots of stuff. Often times if it is current you need, for example in high temperature electric melt furnaces, or Epitaxial Reactors (a high temp chamber for making silicon wafers) you use a higher voltage and lower current for the longer distance branch circuit, then the voltage is dropped using a transformer so that at the unit to get high current but low voltage.

TransistorGeek, 
This is typically done with multiple smaller more manageable cables run in parallel. The rules on applying them are a little more complex because you need to de-rate the cables based on the number of conductors in your raceway etc. etc. Voltage drop is up to you and what your equipment can handle.


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## RIVETER (Sep 26, 2009)

TransistorGeek said:


> I have a purely resistive DC load of 325A at 10V in an industrial application. The load is approximately 50 feet from the power supply. I'm not sure how to find the appropriate wire for this size load at this distance to fit this application. The standard AWG table doesn't appear to go to this high current and the 12.4/0, which seems to be the best fit for the amperage based on a maximum 3% voltage drop, is too large and unweildy.
> 
> Does the NEC standard [FPN's to 210-19(a), 215-2(b), and 310-15] "...a maximum of 3% voltage drop for branch circuits, a maximum of 3% voltage drop for feeders, but a maximum of 5% voltage drop overall for branch circuits and feeders combined" even apply to industrial equipment?
> 
> ...


There are so many people on this forum who just try to impress us with their knowledge it is refreshing to hear from someone like you.


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## SteveBayshore (Apr 7, 2013)

DLO cables installed properly in cable trays. Higher current carrying capacity, a lot more flexible, no derating. Can your equipment operate at a 50% voltage drop?


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## TransistorGeek (Jul 23, 2013)

Thanks for the kind words, Riveter. The power supply is a custom MIL-SPEC supply designed and built specifically for this application, so technically it could be whatever we want it to be (since we aren't yet locked in a contract). It will be a dedicated supply specifically for an electrolytic cell. The wire(s) or cable delivering power to the load will most likely be run through narrow openings but the needed bend radii are unknown. At the moment I'm merely gathering options, so once more information is known about the specific location, we'll be able to quickly select the best solution.

Thanks again gentlemen! :thumbup:


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## HARRY304E (Sep 15, 2010)

RIVETER said:


> There are so many people on this forum who just try to impress us with their knowledge it is refreshing to hear from someone like you.


Well said..:thumbsup:


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## oliquir (Jan 13, 2011)

ive seen a lot of similar equipment with welding cable since it is only 10v


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## IMM_Doctor (Mar 24, 2009)

*No*


Does the NEC standard [FPN's to 210-19(a), 215-2(b), and 310-15] "...a maximum of 3% voltage drop for branch circuits, a maximum of 3% voltage drop for feeders, but a maximum of 5% voltage drop overall for branch circuits and feeders combined" even apply to industrial equipment?


No, NFPA70 is not a standard. NFPA70 NEC is a code. The scope of NFPA70 is for residential, commercial, and industrial PREMISES (buildings), and are enforceable CODES, by the authority having jurisdiction (AHJ).

The NEC is not an engineering design instruction manual.

You are making a specialized industrial application, and you must engineer the minimums to satisfy the application.

The AHJ will only be able to look at the point of attachment of the power supply from the premises wiring, to the main disconnecting means of your specialized industrial equipment. Your equipment must be labeled to satisfy NEC requirements.


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## ponyboy (Nov 18, 2012)

HARRY304E said:


> Well said..:thumbsup:


i thought he was being sarcastic


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## Ultrafault (Dec 16, 2012)

ponyboy said:


> i thought he was being sarcastic


I think it would have been uncalled for to attack someone for posting there math and reasoning in a profesional forum. So I took it at face value.


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## Jlarson (Jun 28, 2009)

SteveBayshore said:


> DLO cables installed properly in cable trays. Higher current carrying capacity, a lot more flexible





JRaef said:


> Lots of stuff. Often times if it is current you need, for example in high temperature electric melt furnaces, or Epitaxial Reactors (a high temp chamber for making silicon wafers).


Agree on the DLO, parallel runs of it was often how we did it in semiconductor equipment.


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