Conduit

Jay Ashworth

Well-Known Member
We have discussed in the past that NEC prohibits hanging lighting fixtures from electrical conduit, that is, thin or thick wall pipe with connectors placed directly in it.

Does it violate the code, though, to, let us say, run one or two pieces of 12/2 what I would call BX, and what I gather people now call MC, through a piece of galvanized pipe intended for use as a lighting support?

In that case the connector protection is provided by the metal jacket of the cable, & I wonder if that's good enough for AHJ's.

If it is acceptable, would additional protection be required where the BX entered and exited such a run through be threaded opening of a tee?

And, because I have participated in these conversations before, please: no "how could you??". :)

If it's not acceptable, just say so...
 
Running a clad cable in a conduit system (NM or MC) is a no. The question is, "Is it really a conduit system?" Well, it's actually a support structure, so you are kind of "out of the frying pan and into the fire." ST could probably give clarity on scripture and verse, but I would suspect your local AHJ would flag it.
 
Google images for "light fixture supported by conduit" and see if you can't feel OK about what you want to do. Not sure what the fixture mounting is but I believe it is OK to support a fixture or pendant a fixture from a condulet, which in my experience does mean rigid ("thick wall" in your terms?) conduit.

Though, since I have an NEC on the floor by my feet - the desk is heaped too high - I look and in fact it says under means of support for luminairs around 410.16 n(F) "Raceway fittings used to support a luminair(s) shall be capable of supporting the weight of the complete fixture and lamp."

Probably more complicated than tha.
 
It is, in fact, a support system; I'm talking about 1.5 or 2 inch threaded water pipe and threaded fittings. Its primary job would be to hold the luminaires up in the air. And it would be supported as such.

It merely happens to be hollow, and a convenient place to run the armored cable... if that's permissible.
 
It seems a better solution than tie wrapping the BX to the outside of the pipe, which is what they have now.
 
It is, in fact, a support system; I'm talking about 1.5 or 2 inch threaded water pipe and threaded fittings. Its primary job would be to hold the luminaires up in the air. And it would be supported as such.

It merely happens to be hollow, and a convenient place to run the armored cable... if that's permissible.

Yes - we run wiring inside handrails and such and steel tubes, so it's fine. Just observe all the rules of access and bending radius etc.
 
One issue I see with it is that the MC cable has rated ampacity in free air. Enclose it in a pipe and what is its ampacity rating? Also, the bend radius of it going into a water pipe T would be too tight for MC cable. Not only would that be a code violation, but it wouldn't go in without damage. That is more likely to catch the inspector's eye than anything else.
 
You mention threaded pipe. Keep in mind that the cast couplers people have used in the past to connect schedule 40 pipe are not suitable for load bearing systems. ANSI 1.4 requires an internal splice sleeve which might stop you from getting your MC cable through the pipe.
 
Running a clad cable in a conduit system (NM or MC) is a no. The question is, "Is it really a conduit system?" Well, it's actually a support structure, so you are kind of "out of the frying pan and into the fire." ST could probably give clarity on scripture and verse, but I would suspect your local AHJ would flag it.

I realized that in my house, MC was run in the original, no out of service, gas pipe, from basement to attic, and it was fine. Considering you can fish MC through walls and floors, I can't see that running it through a pipe - again as long as you observe bending radius and support rules - is a problem. In the handrails I mentioned, the MC entered the rail on a angle so there was no sharp bend. IN this OP's instance, the pipe is a support and as long as it is "strong enough" it should be fine. Passing through a "T" would be an issue of geometry and minimum bend radius and pipe size.
 
Well, I can't edit the original now, but for the record, I've given up worrying about this; I'm just going to have the BX moved up into the suspended ceiling as it should have been originally; I'm not clear why one run goes there and the other doesn't.

Thanks all.
 
AC90 (BX) can be run through EMT if the portion of the cable in the EMT is stripped of the armoured jacket and the correct connector is used. Generally AC90 is only used like this for short runs as it is very difficult and it is easier and more acceptable to put a junction box on the end of the EMT. I have never seen rigid conduit used in this way.
On the other hand you specify using the pipe for lighting support, EMT can not be used in this way at all, and Rigid conduit has severe limitations by code. however if you were intending theatrical lighting fixtures that is a big huge NO. Rigid can only be used to support a light fixture designed to be threaded onto the conduit and both supported and wired in this way.
you can not use conduit to support anything else!
You can not run AC90 through lighting battons (pipes).
thought id do my part to fill in any blanks Jay even though you've already finished.
Sounds like the wire should of been run this way anyways.
 
Alas, Dionysus, it sounds like most of the other responses run counter to yours. :)

You're making the assumption I wanted the pipe to be /an electrical fixture/ ("strip the armor off the BX"), and I thought I was pretty clear that I was trying to avoid that..
 
AC90 (BX) can be run through EMT if the portion of the cable in the EMT is stripped of the armoured jacket and the correct connector is used. Generally AC90 is only used like this for short runs as it is very difficult and it is easier and more acceptable to put a junction box on the end of the EMT. I have never seen rigid conduit used in this way.
On the other hand you specify using the pipe for lighting support, EMT can not be used in this way at all, and Rigid conduit has severe limitations by code. however if you were intending theatrical lighting fixtures that is a big huge NO. Rigid can only be used to support a light fixture designed to be threaded onto the conduit and both supported and wired in this way.
you can not use conduit to support anything else!
You can not run AC90 through lighting battons (pipes).
thought id do my part to fill in any blanks Jay even though you've already finished.
Sounds like the wire should of been run this way anyways.

I assume you are speaking of Canada, not the USA?
 
Yes this is in Canada, I can only assume this is the case in the USA. Our codes don't vary very much.
Hopefully everything came through okay as I am on some serious painkillers with a broken hand with 3 pins.


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Well, I believe that you can run AC through a pipe just like you can run it through a wall in the US, which is why i asked. The pipe is just a part of the building. There is nothing in the wiring methods that prohibit it. Running it through a piece of material that is sold as conduit but being used as a building material and not a part of the required wiring methods is likewise acceptable. No different than using conduit to support a light fixture when it isn't a part of the wiring system but simply a material being used for a support.
 

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