AC or MC cable installed in conduit?

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Sdr96

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I'm looking at an installation where apparently AC cable has been installed in conduit "for more protection." Seems like killing a cockroach with a shotgun. I've not been able to find any code reference why it couldn't be done. In the past I've found where NM can be translated into circular area and the fill tables applied for use in conduit. Is there anything similar for AC or MC cable. My biggest concern would be heat and the need for derating.
 
Yes, You can install AC or MC cable in a raceway, in fact it is specifically mentioned in 330.10(A)(7) for MC cable. As you pointed out if the raceway is used as a wiring method then conduit fill must be maintained. But if you are just using the raceway as a sleeve conduit fill is not a problem.

Chris
 
raider1 said:
Yes, You can install AC or MC cable in a raceway, in fact it is specifically mentioned in 330.10(A)(7) for MC cable. As you pointed out if the raceway is used as a wiring method then conduit fill must be maintained. But if you are just using the raceway as a sleeve conduit fill is not a problem.

Chris
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Chris, how can you use mc or ac in a raceway legally unless it is just a sleeve? You wouldn't be able to terminate the cable properly.
 
Dennis Alwon said:
Chris, how can you use mc or ac in a raceway legally unless it is just a sleeve? You wouldn't be able to terminate the cable properly.
Click to expand...

You have to run 1-1/4" and at the end of the run you put a 1-1/4" rigid coupling with a 1-1/4"-1/2" reducing bushing installed backwards and a 1/2" threaded 2-screw MC connector inside the reducing bushing. Then, you have just enough threads of the reducing bushing sticking out so that you can put it through a 1-1/4" KO in the box and a locknut on the other side to securely terminate the raceways to the box.

I'm actually kinda surprised that you didn't already know this. :roll:


:grin:
 
paul said:
You have to run 1-1/4" and at the end of the run you put a 1-1/4" rigid coupling with a 1-1/4"-1/2" reducing bushing installed backwards and a 1/2" threaded 2-screw MC connector inside the reducing bushing. Then, you have just enough threads of the reducing bushing sticking out so that you can put it through a 1-1/4" KO in the box and a locknut on the other side to securely terminate the raceways to the box.

I'm actually kinda surprised that you didn't already know this. :roll:


:grin:
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I can't imagine doing it either. First off, why would you have a complete raceway and pull mc in it? Secondly, how many boxes would accommodate 1 1/4" KO's if you are running a small size mc as 12/3 or so.

Sorry I didn't know it but I rarely use mc and would never have a complete raceway with mc installed inside it.

BTW, I am still not sure of what you are describing.
 
Dennis Alwon said:
I can't imagine doing it either. First off, why would you have a complete raceway and pull mc in it? Secondly, how many boxes would accommodate 1 1/4" KO's if you are running a small size mc as 12/3 or so.

Sorry I didn't know it but I rarely use mc and would never have a complete raceway with mc installed inside it.

BTW, I am still not sure of what you are describing.
Click to expand...


* Tongue was planted firmly in cheek with my post. I'm with you on this 100%.
 
paul said:
* Tongue was planted firmly in cheek with my post. I'm with you on this 100%.
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Sorry I missed the humor. I should have realized it. :grin:

Actually I wanted to say "Are you out of your mind", but I was being nice for a change. :)
 
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Sdr96 said:
I'm looking at an installation where apparently AC cable has been installed in conduit "for more protection." Seems like killing a cockroach with a shotgun. I've not been able to find any code reference why it couldn't be done. In the past I've found where NM can be translated into circular area and the fill tables applied for use in conduit. Is there anything similar for AC or MC cable. My biggest concern would be heat and the need for derating.
Click to expand...

I think its great that an engineer is even asking or careing
while maybe over kill have you visited the job ? Often on paper things simply are not seen .
 
paul said:
You have to run 1-1/4" and at the end of the run you put a 1-1/4" rigid coupling with a 1-1/4"-1/2" reducing bushing installed backwards and a 1/2" threaded 2-screw MC connector inside the reducing bushing. Then, you have just enough threads of the reducing bushing sticking out so that you can put it through a 1-1/4" KO in the box and a locknut on the other side to securely terminate the raceways to the box.

I'm actually kinda surprised that you didn't already know this. :roll:


:grin:
Click to expand...

That is a super cost effective way to do it. :)
Or you could take the same 1 1/4" and run it into a 10"x10"x4" box, them put a smaller 4" sq. box inside of that and run the MC to the 4" sq. can't have to much protection.
 
Dennis Alwon said:
Chris, how can you use mc or ac in a raceway legally unless it is just a sleeve? You wouldn't be able to terminate the cable properly.
Click to expand...

I didn't say it would be easy, just that 330.10(A)(7) specifically permits MC cable to be installed in any raceway. It would be tough to terminate and secure and support the cable.:D

Chris
 
Jim W in Tampa said:
I think its great that an engineer is even asking or careing. while maybe over kill have you visited the job ? Often on paper things simply are not seen
Click to expand...

As far as asking the question, it's easy when you're an engineer who
1. admits that you don't know everything,
2. knows that paper and real life are two completely different worlds
3. has done enough DIY adds and mods to appreciate the craft.

My first thought in a situation like this is to visit the job to get a feel with my own eyes ears, hands, etc. Unfortunately, of all places, this is in the Middle East, and not one of the resort areas either. I am reviewing some photos, an internal site visit report, and an external report. It looks as though conduit was installed as a sleeve and then AC cable pulled through it. Near the termination points at boxes, fixtures, etc., the conduit stops short and the cable connects to the box.
 
Sdr96 said:
It looks as though conduit was installed as a sleeve and then AC cable pulled through it. Near the termination points at boxes, fixtures, etc., the conduit stops short and the cable connects to the box.
Click to expand...

I believe this is code compliant, IMO
 
Sdr96 said:
It looks as though conduit was installed as a sleeve and then AC cable pulled through it. Near the termination points at boxes, fixtures, etc., the conduit stops short and the cable connects to the box.
Click to expand...

I have seen this before.... in a 50 year old building we were rewiring.
 
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