Another question about Romex in conduit

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bhsrnd

bhsrnd

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Fort Worth, TX
I've already read some of the threads pertaining to NM in conduit, but I present the following scenario:

A residential installation. An approx. 6' section of 2" EMT terminates to an LB at each end. One LB terminates to a breaker panel located on the exterior side of the residence and the other LB has a fitting installed which is pushed through a sealed hole in the side of the house leading into the attic. There is no box on the attic side where the LB fitting protrudes. NM is pulled through the attic side of the LB and fitting into the breaker panel.

Which one of the following would be a Code compliant NM installation method for the above scenario?

1. Strip off enough NM sheath and pull only the insulated conductors (including bare ground) through the conduit so as to not take up so much room for conduit fill now that the sheath is gone? (To my understanding this would alter the NM cable and "void" its UL listing or rating)

2. Leave the sheath intact and pull the NM through the conduit allowing the NM to only occupy 53% of the conduit fill as mentioned in another thread? I'm trying to remember the Code section which talks about NM and conduit fill but having a brain lapse at the moment.


I know the consensus is that NM is despicable, part of the President's "Axis of Evil", a cousin to Satan, etc. All that aside, is either #1 or #2 Code compliant or is there a better way to accomplish this using the 2" EMT?

EDIT: Punctuation.
 
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bhsrnd said:
I've already read some of the threads pertaining to NM in conduit, but I present the following scenario:

A residential installation. An approx. 6' section of 2" EMT terminates to an LB at each end. One LB terminates to a breaker panel located on the exterior side of the residence and the other LB has a fitting installed which is pushed through a sealed hole in the side of the house leading into the attic. There is no box on the attic side where the LB fitting protrudes. NM is pulled through the attic side of the LB and fitting into the breaker panel.

Which one of the following would be a Code compliant NM installation method for the above scenario?

1. Strip off enough NM sheath and pull only the insulated conductors (including bare ground) through the conduit so as to not take up so much room for conduit fill now that the sheath is gone? (To my understanding this would alter the NM cable and "void" its UL listing or rating)

2. Leave the sheath intact and pull the NM through the conduit allowing the NM to only occupy 53% of the conduit fill as mentioned in another thread? I'm trying to remember the Code section which talks about NM and conduit fill but having a brain lapse at the moment.


I know the consensus is that NM is despicable, part of the President's "Axis of Evil", a cousin to Satan, etc. All that aside, is either #1 or #2 Code compliant or is there a better way to accomplish this using the 2" EMT?

EDIT: Punctuation.
Click to expand...

1. I have done this many times, using a choke connector where the romex enters, and pulling the skinned romex through emt, but I'm not positive what this does to the rating, or if it violates code off the top of my head...

2. Chapter 9, note 9.

3. Romex is not evil, it is a perfectly acceptable method assuming it is used properly. How else would you rope a house without it costing a fortune?
 
nyerinfl said:
1. I have done this many times, using a choke connector where the romex enters, and pulling the skinned romex through emt, but I'm not positive what this does to the rating, or if it violates code off the top of my head...

2. Chapter 9, note 9.

3. Romex is not evil, it is a perfectly acceptable method assuming it is used properly. How else would you rope a house without it costing a fortune?
Click to expand...

Thank you for the reply. I should have clarified the comment about NM being "evil" in that some posters hold this opinion based on other threads I've read :). I agree that it would be extremely expensive (if not completely cost prohibitive) to use individual THHN type conductors and conduit all over a house.
 
To clarify, when I speak of the chokers, I'm not talking about for 2", I'm talking 1/2 and 3/4. You could always put your 2" into a trof, then enter your romex into it, skin it from there and feed it through the 2". Assuming your derating is ok I wouldn't see a problem with that. I do similar installations like this all the time in commercial for an MC changeover.
 
The only rule that lets you run NM in a raceway and terminate that raceway at a panel is the Exception to 312.5. It does not appear that this installation meets the conditions of the exception.
Don
 
Stripping NM does NOT allow you to then run it in conduit as individual THHN conductors. The required labeling is on the sheath, not on the conductors. Once you remove the sheath, the individual conductors do not have the required labeling. I believe Don has given you the correct answer. The installation that you are proposing cannot be made NEC compliant.
 
don_resqcapt19 said:
The only rule that lets you run NM in a raceway and terminate that raceway at a panel is the Exception to 312.5. It does not appear that this installation meets the conditions of the exception.
Don
Click to expand...

Which part of the exception would you say this does not meet? I could see how (e) would not be met if #1 in the scenario were used.
 
bhsrnd said:
One LB terminates to a breaker panel located on the exterior side of the residence...
Click to expand...

Do you intend to run the NM in an exterior location? Regardless of how it gets there, an exterior panel is a wet location and the conduit point is irrelevent - unless you're talking about UF instead. I remember a thread a while back where someone ran a piece of NM into the back of an exterior JB and it wicked enough water back inside to cause some unwanted arcing in an interior box - or something like that. If you are indeed running to an exterior location and use UF, you can't very well split the strands, so just calculate cross sectional area in the normal non-round fashion.
 
Here is a crude drawing of what I'm talking about. Please don't be jealous of my extensive artistic abilities.:D

Drawing1.jpg
 
looks like your method #2 would still violate (b) ?

plus, with 53% fill, wouldn't you still have to derate because of the number of conductors ?

if this is the easiest way to get to the panel, the easiest compliant method I can think of is just use THHN and put a box on the end of your conduit(s) at the attic and make up your splices there.
 
This method has been illegal since 2005 I believe, but I still do it all the time and will continue to do it until I'm forced to do otherwise.

All of our services/panels here are exterior and the common method is to use EMT as a sleeve to protect the romex when adding circuits.

I'd skip the LB at the top and use a 8x8x4 wp box. You have more room and it's cheaper. I'd skip the lb at the bottom and just hit the top of the panel with a sealing locknut or meyers hub. You won't hane to fight the cables as much.

I haven't been turned down yet because logic still prevails. In real life, if the inside of the panel is not a wet location, the inside of the conduit should not be either.
 
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220/221 said:
This method has been illegal since 2005 I believe, but I still do it all the time and will continue to do it until I'm forced to do otherwise.
Click to expand...

Why is this comment not hard to believe? :roll: And remember its only your logic, as your disclaimer reminds us.
 
220/221 said:
This method has been illegal since 2005 I believe, but I still do it all the time and will continue to do it until I'm forced to do otherwise.
Click to expand...

Do you put that on the trucks? :grin:

Ignoring the codes until I'm forced to do otherwise
 
IMO, you have 2 choices. Either sleeve UF in the conduit or run thwn wire and install a JB in the attic. From there you can run NM.
 
Vaughn,
The exception that I cited only applies if the raceway enters the top of the panel. Also NM is not permitted in exterior conduit. This was made clear with a new rule in the 2008 code.
Don
 
Maybe this was just an academic question and not a real life quandary, but I would but a sub in the attic and just pull a feeder thru the pipe - seems a million times easier. Also then we could discuss whether you can pull se cable thru that pipe ;)
 
electrofelon said:
Maybe this was just an academic question and not a real life quandary, but I would but a sub in the attic and just pull a feeder thru the pipe - seems a million times easier. Also then we could discuss whether you can pull se cable thru that pipe ;)
Click to expand...

We could also discuss whether the height clearance can be made and then of course the ambient temp in an attic, etc.... :grin:
 
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