NM to outside panel

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kikomera

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st pete, fl, usa
My area has finally started to enforce the 2014 NEC and I keep running into the same problem: Inspectors are failing inspections due to NM wire exiting from the attic into a conduit and then into the main panel. They point out that NM is not rated for outside use, and I get that, but they don't follow up with how it's suppose to be done now. One inspector told me to start doing everything in UF, and another told me I'm going to need junction boxes inside transitioning every conductor from NM into individual THWN conductors, which seems excessive. I'm scheduled to do several panel changes and HVAC installs and I'm starting to get very anxious about the proper "new" way of doing things. So my question is this: when running NM circuits in the attic of a residential home, how do I proprely exit the attic and land them in an exterior panel? Thank you for your time
 
kikomera said:
So my question is this: when running NM circuits in the attic of a residential home, how do I proprely exit the attic and land them in an exterior panel? Thank you for your time
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There is no NEC compliant way to exit the attic to outside and continue the NM all the way to the panel in pipe.

In the case you describe I would switch to THWN just before I left the attic.
 
kikomera said:
My area has finally started to enforce the 2014 NEC and I keep running into the same problem: Inspectors are failing inspections due to NM wire exiting from the attic into a conduit and then into the main panel. They point out that NM is not rated for outside use, and I get that, but they don't follow up with how it's suppose to be done now. One inspector told me to start doing everything in UF, and another told me I'm going to need junction boxes inside transitioning every conductor from NM into individual THWN conductors, which seems excessive. I'm scheduled to do several panel changes and HVAC installs and I'm starting to get very anxious about the proper "new" way of doing things. So my question is this: when running NM circuits in the attic of a residential home, how do I proprely exit the attic and land them in an exterior panel? Thank you for your time
Click to expand...

How far will you need to extend these circuits? I think I may see a lot of arc fault breakers in your future.

Better check that out before pricing any panel swaps.
 
kikomera said:
My area has finally started to enforce the 2014 NEC and I keep running into the same problem: Inspectors are failing inspections due to NM wire exiting from the attic into a conduit and then into the main panel. They point out that NM is not rated for outside use, and I get that, but they don't follow up with how it's suppose to be done now. One inspector told me to start doing everything in UF, and another told me I'm going to need junction boxes inside transitioning every conductor from NM into individual THWN conductors, which seems excessive. I'm scheduled to do several panel changes and HVAC installs and I'm starting to get very anxious about the proper "new" way of doing things. So my question is this: when running NM circuits in the attic of a residential home, how do I proprely exit the attic and land them in an exterior panel? Thank you for your time
Click to expand...

you don't -- run down inside the exterior wall to the back of the panel -- you could have the builder make a chase on the exterior & put siding on it
 
wwhitney said:
Maybe box out the conduit with siding so it is no longer in a wet location?

Cheers, Wayne
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Sierrasparky said:
I agree with Wayne
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I agree, code compliant and why I carefully worded my post to include 'outside'. If the conduit does not go outside you are good to go.

Now that said, having conduits or cables boxed in is not a very realistic option for most circuit additions.


Yes, I can install those few new outlets you want on the second floor but after I am done you need a carpenter and painter with matching siding and / or paint. :roll:

Switching to THWN in the attic is easy and fast, you can also run a smaller conduit then if you where snaking cables into them.

To each their own. :)
 
kikomera said:
My area has finally started to enforce the 2014 NEC and I keep running into the same problem: Inspectors are failing inspections due to NM wire exiting from the attic into a conduit and then into the main panel. They point out that NM is not rated for outside use, and I get that, but they don't follow up with how it's suppose to be done now. One inspector told me to start doing everything in UF, and another told me I'm going to need junction boxes inside transitioning every conductor from NM into individual THWN conductors, which seems excessive. I'm scheduled to do several panel changes and HVAC installs and I'm starting to get very anxious about the proper "new" way of doing things. So my question is this: when running NM circuits in the attic of a residential home, how do I proprely exit the attic and land them in an exterior panel? Thank you for your time
Click to expand...
I don't understand the reference to the 2014 NEC. The rule that applies first appeared in the 2008 code..
 
iwire said:
Now that said, having conduits or cables boxed in is not a very realistic option for most circuit additions.
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Agreed. I got the impression from the OP that sometimes this comes up as an existing non-compliant sleeve for multiple circuits. (Could be my imagination.) In which case boxing out the conduit might be easier than splicing all the circuits, assuming there is not also a derating issue.

Cheers, Wayne
 
If the inside of that conduit in the OP's question is considered a wet location, how does it get "arranged to drain" before the "wetness" drains into the panel?
 
Michael15956 said:
If the inside of that conduit in the OP's question is considered a wet location, how does it get "arranged to drain" before the "wetness" drains into the panel?
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By coming into the side with an LB and drilling a drain hole.
I never bring conduits into the top of an enclosure that is in a wet location unless there is absolutely no other way to do it.
 
kikomera said:
My area has finally started to enforce the 2014 NEC and I keep running into the same problem: Inspectors are failing inspections due to NM wire exiting from the attic into a conduit and then into the main panel. They point out that NM is not rated for outside use, and I get that, but they don't follow up with how it's suppose to be done now. One inspector told me to start doing everything in UF, and another told me I'm going to need junction boxes inside transitioning every conductor from NM into individual THWN conductors, which seems excessive. I'm scheduled to do several panel changes and HVAC installs and I'm starting to get very anxious about the proper "new" way of doing things. So my question is this: when running NM circuits in the attic of a residential home, how do I proprely exit the attic and land them in an exterior panel? Thank you for your time
Click to expand...
This is pretty basic and as don said has nothing to do with the 2014 code. UF cable with or without pvc or thwn and j-boxes. If you are talking an attic air handler for the AC around here we run it with the line set in the sleeve the HVAC guys put up. (don't know how they do it in your area.) It still needs to be UF in that sleeve.
 
Michael15956 said:
If the inside of that conduit in the OP's question is considered a wet location, how does it get "arranged to drain" before the "wetness" drains into the panel?
Click to expand...

Entering the top of an exterior panel with a Myer's hub would help -- The design is for keeping standing water out of the panel -- generally the moister will follow the wiring inside the conduit so arrange a drip loop so that any condensation will drip to the bottom of the panel -- if you have that much excessive moisture entering the panel with a side ko & LB that you need a weep hole drilled maybe sleeve the branch circuit with an approved LFMC.
 
I agree that using UF or switching to THWN is a Code compliant way to go. Now, I have no Code reference for this but I remember a CEU class that I once took where the instructor claimed that if you are running PVC on the outside of a house and just stubbing into an attic and a basement it wasn't considered "outside" because any condensation that "might" build up would evaporate. If you terminate any or both ends it would then be considered "outside" and subject to condensation and as such would require wiring to be rated for outdoors.

As it turns out, most of the EI's in my area don't believe in this theory and I have failed several inspections. So, now I generally use UF as a rule.
 
kikomera said:
My area has finally started to enforce the 2014 NEC and I keep running into the same problem: Inspectors are failing inspections due to NM wire exiting from the attic into a conduit and then into the main panel. They point out that NM is not rated for outside use, and I get that, but they don't follow up with how it's suppose to be done now. One inspector told me to start doing everything in UF, and another told me I'm going to need junction boxes inside transitioning every conductor from NM into individual THWN conductors, which seems excessive. I'm scheduled to do several panel changes and HVAC installs and I'm starting to get very anxious about the proper "new" way of doing things. So my question is this: when running NM circuits in the attic of a residential home, how do I proprely exit the attic and land them in an exterior panel? Thank you for your time
Click to expand...

Code Nazi's run amuck. What has happened to common sense? Have we had sooo many NM-B failures in exterior conduit, along with the subsequent fires? :happysad: I would venture to say that there is more danger to safety because of the difficulty in stripping the outer sheath of UF when the conductors become exposed.
 
mwm1752 said:
Entering the top of an exterior panel with a Myer's hub would help -- The design is for keeping standing water out of the panel -- generally the moister will follow the wiring inside the conduit so arrange a drip loop so that any condensation will drip to the bottom of the panel -- if you have that much excessive moisture entering the panel with a side ko & LB that you need a weep hole drilled maybe sleeve the branch circuit with an approved LFMC.
Click to expand...
The problem is that if you have rigid conduit running vertically out of the top of an enclosure and there is a coupling in the vertical conduit, it will leak at the coupling.

In my opinion, it would not be unreasonable to read the "arrange to drain" rule as prohibiting a top entry in wet locations.
 
goldstar said:
I agree that using UF or switching to THWN is a Code compliant way to go. Now, I have no Code reference for this but I remember a CEU class that I once took where the instructor claimed that if you are running PVC on the outside of a house and just stubbing into an attic and a basement it wasn't considered "outside" because any condensation that "might" build up would evaporate. If you terminate any or both ends it would then be considered "outside" and subject to condensation and as such would require wiring to be rated for outdoors.

As it turns out, most of the EI's in my area don't believe in this theory and I have failed several inspections. So, now I generally use UF as a rule.
Click to expand...
The code wording doesn't say anything about where the conduit terminates. It applies where the conduit is installed in an above grade wet location. Note this is not just exterior locations....it applies in interior wet locations as well as exterior wet locations.
 
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