# Air Conditioning - Romex in flexible liquid tight



## riniboo (Apr 11, 2010)

I hired an Air Conditioning company to install a unit for our house last year, and recently I am reading on the electrical code (since I am planning for other projects in the house) that I learned that it is not up to code to put Romex in flexible liquid tight conduit. 

They use Romex NMD90 10/3 (Canadian version of Type NM-B) cable running from the main panel in basement to outside. There is a breaker outside (a grey box), then it runs to the air conditioning unit. The 2 wires are protected by the flexible liquid tight conduit.... my question is, is this violating the code??? 

The information I have is because of the insulation jacket on Romex, when it is sitting inside the conduit (regardless of PVC or flex), it may overheat. 

When I walked around I saw all the neighbors are having similar setup, some even have 10 feet of those liquid tight conduit. 

R.B.


----------



## beenthere (Oct 11, 2008)

Is the NM ran to the disconnect/outside breaker in conduit, or just the wire from the outside breaker box to the unit.

Often, the run from the main panel box to the outside box is a straight shot, and no conduit is used. The sealtite from the outside box to the condenser usually has THHN/THWN wire, instead of NM.


----------



## brric (Mar 5, 2010)

It is a violation, not because of potential overheating but because it is a wet location. NM cable is not suitable for use in wet locations.


----------



## rjniles (Feb 5, 2007)

Running NM in flex conduit outside to an AC unit is a code violation. But it us also very common. My AC was replaced last year and that's exactly how it was done. It was also inspected and passed.


----------



## InPhase277 (Feb 9, 2008)

Code violation, yes. Dangerous, no.


----------



## Arrow3030 (Apr 19, 2015)

Someone made the argument that inside the flex is a dry location. Sounded good to me so I roll with it.


----------



## Jim Port (Sep 21, 2007)

Arrow3030 said:


> Someone made the argument that inside the flex is a dry location. Sounded good to me so I roll with it.


All you need to do is read the Article 100 definition of Location, Wet. Conduit outside is considered a wet area.


----------



## beenthere (Oct 11, 2008)

Arrow3030 said:


> Someone made the argument that inside the flex is a dry location. Sounded good to me so I roll with it.


Seen more then 1 sealtite run have water in it.


----------



## Oso954 (Jun 23, 2012)

Time to ask the OP for his location. 
I think he needs CEC, not NEC.


----------



## WyrTwister (Jul 22, 2013)

My understanding is recently manufactured Romex has THHN insulated wire inside the jacket .

If I am correct , if you are worried , pull the Romex out of the flex ( with the power off ) , remove the jacket. & put the wire back in the Romex .

Re-terminate & turn the power back on .

But I personally would go hunt something more imporeant to obcess about .

It will last longer than you , me or the condenser will .

God bless

Wyr


----------



## WyrTwister (Jul 22, 2013)

Oops! Sorry . :-(

Put the wire back into the flex .


God bless
Wyr


----------



## rjniles (Feb 5, 2007)

WyrTwister said:


> My understanding is recently manufactured Romex has THHN insulated wire inside the jacket .
> 
> If I am correct , if you are worried , pull the Romex out of the flex ( with the power off ) , remove the jacket. & put the wire back in the Romex .
> 
> ...


That will not make it compliant. Even if it is THWN, it is not marked as such. My advice is leave it be.


----------



## Arrow3030 (Apr 19, 2015)

When sleeving romex it should continue it it's sheath through the pipe


----------



## riniboo (Apr 11, 2010)

Honestly speaking I am just curious, not going to re-do it... I am not that crazy. I agree with InPhase277 - code violation yes, dangerous no. I guess most houses are done violating the code at least in my city. LOL.. Indeed I visited my friends houses just for my own curiosity to check it out. 

If my information is correct, the PROPER way is to use NMD90 (NM-B in US) from the panel and then transition to T90 (THHN/THWN in US) in a junction box inside the house, then pass the T90/THHN/THWN in the flexible liquid tight conduit to outside, to the disconnect metal box outside, then use T90/THHN/THWN again in conduit to the air conditioning compressor. 

If this is the way, I should be able to see a junction box inside the house - but I couldn't see them in any of my friend's house. One of my friend's Romex cable was stapled to the joist, of course without running board!! My house is better because I hired the pot light installer who is a licensed electrician prior to the Air Con installation, so the AC guy used the same hole for his cable.


----------



## rjniles (Feb 5, 2007)

riniboo said:


> Honestly speaking I am just curious, not going to re-do it... I am not that crazy. I agree with InPhase277 - code violation yes, dangerous no. I guess most houses are done violating the code at least in my city. LOL.. Indeed I visited my friends houses just for my own curiosity to check it out.
> 
> If my information is correct, the PROPER way is to use NMD90 (NM-B in US) *from the panel and then transition to T90 (THHN/THWN in US) in a junction box inside the house, then pass the T90/THHN/THWN in the flexible liquid *tight conduit to outside, to the disconnect metal box outside, then use T90/THHN/THWN again in conduit to the air conditioning compressor.
> 
> If this is the way, I should be able to see a junction box inside the house - but I couldn't see them in any of my friend's house. One of my friend's Romex cable was stapled to the joist, of course without running board!! My house is better because I hired the pot light installer who is a licensed electrician prior to the Air Con installation, so the AC guy used the same hole for his cable.


If you run the NM from the panel directly thru the wall into the back of the disconnect (with a NM connector), I think you will not find an inspector that will object.


----------



## riniboo (Apr 11, 2010)

Good point indeed, but in our area.... from what I have seen the disconnect usually is installed with certain height above grade, maybe because of snow?? I am not expert. Since the cable is coming from the basement, it's too close to the ground to install the disconnect. Is there a minimal height requirement for disconnect installation? Maybe snow is not an issue, because even you install 3-4 feet above ground, snow can each that too in some winters.. LOL.. 

Just curious, say there is no snow and height is not an issue. If NM is coming directly thro wall to the back of disconnect, is the NM connector able to provide enough water proofing?


----------



## Jim Port (Sep 21, 2007)

The interface between the wall and disconnect should be caulked. The connector should not be subject to rain, snow.


----------

