Feeder cables wiring installation through block or concrete walls

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arscaribe

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I would like to know if is permitted by NEC to install feeder cables (let say a run of four single conductors THHN) from a MDP (main distribution panel) through the walls of a commercial building to a main disconnect switch on an equipment. The installation of the conductors are without any type of conduit (metallic or non-metallic) just the cables directly in contact with the wall concret or blocks.

Thank you
 
I am inclined to agree, but whether it is a hazard or not is something else. It seems like a fairly common practice to chop a hole in a concrete wall and feed conductors through between two enclosures mounted on either side.
 
petersonra said:
I am inclined to agree, but whether it is a hazard or not is something else. It seems like a fairly common practice to chop a hole in a concrete wall and feed conductors through between two enclosures mounted on either side.
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If the conductors are supported clear of the concrete by the bushings on the two enclosures, that is very different from laying a longer run of conductors into place supported by the concrete or able to rub against the concrete. Although an inspector still may not allow even that.
 
GoldDigger said:
If the conductors are supported clear of the concrete by the bushings on the two enclosures, that is very different from laying a longer run of conductors into place supported by the concrete or able to rub against the concrete. Although an inspector still may not allow even that.
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why is it different? it is still not a chapter 3 wiring method.
 
petersonra said:
why is it different? it is still not a chapter 3 wiring method.
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It is no different in terms of the applicable code, just in the underlying safety hazard that led to that code requirement being made. :)

I was trying to address the "fairly common practice", even though it is not code compliant.
 
PowerSupportElec said:
I've never seen that. Usually they will either stub conduits or install a piece of trough between the two enclosures.
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I can't say I recall seeing a trough in such a case, but I have seen a fair number of conduits of various kinds, along with just holes the wires run through.

I just do not see it as that much of a hazard that I would worry about it all that much despite not being code.

I see EMT and various kinds of flex that have come loose pretty regularly that bother me more.
 
petersonra said:
I can't say I recall seeing a trough in such a case, but I have seen a fair number of conduits of various kinds, along with just holes the wires run through.

I just do not see it as that much of a hazard that I would worry about it all that much despite not being code.

I see EMT and various kinds of flex that have come loose pretty regularly that bother me more.
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I've seen people run loose #14 THHN out of a receptacle box behing their stove up through the wall into the JB on the vent fan above. This is ok too? It's only a few amps in those conductors, not like a feeder. And it's only drywall that the conductors are running through, not abrasive concrete block.


:thumbsup:
 
PowerSupportElec said:
I've seen people run loose #14 THHN out of a receptacle box behing their stove up through the wall into the JB on the vent fan above. This is ok too? It's only a few amps in those conductors, not like a feeder. And it's only drywall that the conductors are running through, not abrasive concrete block.


:thumbsup:
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There is a difference between "not to code" and "hazardous".

I have seen stuff wired in 2 wire lamp cord. Not to code and no EGC so actually hazardous, where as the same thing wired in 2c/g SO is perfectly safe but not to code either.

I have gotten to the point where I worry less about things that do not actually present some hazard than actual hazards in existing work.
 
petersonra said:
There is a difference between "not to code" and "hazardous".

I have seen stuff wired in 2 wire lamp cord. Not to code and no EGC so actually hazardous, where as the same thing wired in 2c/g SO is perfectly safe but not to code either.

I have gotten to the point where I worry less about things that do not actually present some hazard than actual hazards in existing work.
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I agree with you on that.

But feeders running through a block wall like described is not something I would consider safe or professionally installed. I think it's hack work, and IMO it's more dangerous than the THHN running in a wall like I described above, which most people would also consider hack work.
 
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