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MCC wire ampacity
- Thread starter lmorriso
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friebel
Senior Member
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- Pennsville, N.J.
Re: MCC wire ampacity
I am puzzled by your question of the wiring in a bucket that is in a MCC, from the Breaker to the contactor.
The wiring is sized for the size bucket that you are working with. For example: A size one starter, will take up to 10 HP, 460 volts, wheras a size 3 starter will go up to a 50 HP, 460 volts.
The manufacturer does the sizing of the wire, and it has nothing to do with a raceway.
Am I stating your question properly.
I am puzzled by your question of the wiring in a bucket that is in a MCC, from the Breaker to the contactor.
The wiring is sized for the size bucket that you are working with. For example: A size one starter, will take up to 10 HP, 460 volts, wheras a size 3 starter will go up to a 50 HP, 460 volts.
The manufacturer does the sizing of the wire, and it has nothing to do with a raceway.
Am I stating your question properly.
Re: MCC wire ampacity
In an attempt to povide an accurated answer for the poster, it must be clarified whether the wire was factory installed, and if so was it a UL listed assemble from the factory, or field wired and installed.
This is they way I addressed this issue in the past where an AHJ has red tagged enclosed control or an MCC:
Factory MCC assemblies are commonlly tested per UL standards and must pass the UL tests to be able to be UL listed. This does not mean that all MCCs are UL listed but most are.
If the MCC comes from a factory that is authorized to place a UL sticker on it, all of the internal components, wires, enclosure, etc. comply with the UL tests. Wire sizes within the enclosure are often times smaller than would be if it were to be built using the NEC.
But keep in mind that if the MCC has a UL label and has not been modified of altered in the field then it is allowed per article 110.2 and 110.3.
When you start modifying the wiring in the field then it must comply with the applicable sections of the NEC and should be inspected by the AHJ.
In an attempt to povide an accurated answer for the poster, it must be clarified whether the wire was factory installed, and if so was it a UL listed assemble from the factory, or field wired and installed.
This is they way I addressed this issue in the past where an AHJ has red tagged enclosed control or an MCC:
Factory MCC assemblies are commonlly tested per UL standards and must pass the UL tests to be able to be UL listed. This does not mean that all MCCs are UL listed but most are.
If the MCC comes from a factory that is authorized to place a UL sticker on it, all of the internal components, wires, enclosure, etc. comply with the UL tests. Wire sizes within the enclosure are often times smaller than would be if it were to be built using the NEC.
But keep in mind that if the MCC has a UL label and has not been modified of altered in the field then it is allowed per article 110.2 and 110.3.
When you start modifying the wiring in the field then it must comply with the applicable sections of the NEC and should be inspected by the AHJ.
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