running NM cable in conduit

[franklin pug]

I have to wire two 20A circuits in my garage and don't want to tear the walls apart. I was planning on running 3/4" conduit along the outside of the walls (on the inside of the garage of course) and connecting my receptacles with appropriate conduit boxes. I plan on running two 12/2 NM cables inside the 3/4" PVC conduit.

The line in is from my basements panel, which is connected to my garage.

Sound okay?

[FINER9998]

You might consider bringing 12/3 in, using the black for 1 20 amp circuit and the red for the second circuit. The white would be a shared common. Be sure to ground all switches and receptacles when using plastic conduit.

[franklin pug]

I would rather run inflexible conduit, as I can easily snag power from the box in the basement and seal the conduit junction box. Also, I can run 2 circuits through the same peice of conduit.

I don't want to get fancy and use 12/3 to run two circuits. I am happy to run 2 lines through the same conduit and then have them split at a "T" and run to their respective GFCI receptacles. That way they terminate independently and simply at the panel.

Does anyone know the fill limit for 3/4" conduit?

[wbrooks]

ATG you are kidding right?
Most of our igloos actually have 120/240 V 60 HZ just like you guys.
It takes a dog load of juice to keep them igloos from meltin between March and December ;)
You may be surprised where a good deal of the power used by your northern states comes from - Hint - Not the USA.

Sorry FP don't know the limits for conduit

[PLUMBER RICK]

as far as i know, romex is not allowed to be pulled into conduit. it creats a heat issue. it would be much better to pull 12 gauge, thhn wire. 2 hots, a nutreal and a ground. this will give you 2 - 20 amp circuits. be sure to pull the 2 hots from the 2 opposite sides of the panel. if not the nutreal will be overloaded up to 40 amps. with the proper 2 hots, opposite (legs) the nutreal could actuall pull 0 amps with both hots drawing 20 amps each:eek:

personally i would pull #8 and install a sub panel. this would give 40 amps a side and the posibility of 240 volts for future use. it will fit into 3/4'' pvc with 4-#8, 2 hots, nutreal, ground.

see what the sparkies say about this:confused:

rick.

[Roadrunner]

as far as i know, romex is not allowed to be pulled into conduit. it creats a heat issue.
personally i would pull #8 and install a sub panel. this would give 40 amps a side and the posibility of 240 volts for future use. it will fit into 3/4'' pvc with 4-#8, 2 hots, nutreal, ground.

see what the sparkies say about this:confused:

rick.

This begs an interesting question that I'm sure will need a sparkie reply. I have an exterior breaker box, I need two 20A circuits to the garage, at the other end of the house no less. I will have to run the wire up the outside of the house (conduit) and across the attic (Romex) I'd like to do this w/o a junction box, but it appears that by code, I may be a bit screwed. Advise on how to do. The hole coming through the top plate in the attic is quite full, so I'm not sure going through the drywall from the inside is an option. Would it be code to transfer from 4-#6 THHN(red, black, white, green) in the conduit to a #6-3 w/g to run across the attic in a junction box right inside the gable end wall? I'm proposing a 50A breaker to feed the box, and the run is across a 45' attic, 8 up and 8 down on each end for a total run of 61 feet.
I figure I'll go with the heavy wire for the better to have it and not need it than need it and not have(redo) it.

[franklin pug]

thats a bummer - I was hoping to install the conduit.

Is it okay to run BX instead of conduit then, and attach it directly to the drywall (with clamps into studs of course).

If this is okay, what type of boxes do I use for the wall?

Lastly, am I required to connect the incoming feed (through a 2x6 from the basement panel) to a junction box before running the circuit?

[wwsmith]

Pug, when I used to help wire hot tubs we used to use NM cable. At the time it was cheaper for whatever reason than buying just #12 cable. We would simply remove the outer sheath (shell?) using a simple tool you can by at any box store that pinches around the Romex and you pull it to split the sheath open. It can be bought for about $2 US. Then we would pull wire out and run the wire through the conduit. I don't know about all places, but it is against code to pull Romex through conduit with the outer sheath on in AZ and MT.

[franklin pug]

So i could simply rip the sheath off of 12/2 NM, fish the individual conducters through and be okay?

How would I keep track if i was running two separate circuits through the same conduit?

[Bob D.]

I wonder, is the insulation on the individual conductors you rip out of NM cable OK to use without the outer jacket?

I know that inside a box it is, but for longer runs through conduit I wonder.

[wwsmith]

Bob, I do not know the answer to your question and a valid point. The gentleman I worked with in AZ doing this work was a master electrician and I was simply a "young peon" earning some extra cash doing some of the less envious manual labor in the projects and helping out where I could while in college. I have also seen other electricians do it.

But I do admit I am in no way an expert electrician and only did as told from someone who was and took it to be correct. I suppose one of the sparkies on here could answer that question better. Either way, I have not looked in a while and it may be cheaper to buy individual wires of the proper gauge now. I just bought 250 ft of 12/2 Romex a couple of weeks ago for a finishing a couple of new rooms in my basement and it was $85!

[FINER9998]

As Rick suggested, pull 4 wires - red, black, white and green. Red, white and green are one circuit and black, white and green are the other circuit. The white(neutral) and green(ground) are common to both circuits.

[franklin pug]

Okay just got some info from the elecrical inspector

PVC is against code to run indoors - I have to run steel conduit. I think PVC releases toxic gases if it melts during a fire.

NMC can't be run in any conduit if it has a sheath. I need to buy #12 wire individually and use an insulated ground in my connections.

Thanks for the suggestions fellas.

[Polar Sparky 1224]

I would rather run inflexible conduit, as I can easily snag power from the box in the basement and seal the conduit junction box. Also, I can run 2 circuits through the same peice of conduit.

I don't want to get fancy and use 12/3 to run two circuits. I am happy to run 2 lines through the same conduit and then have them split at a "T" and run to their respective GFCI receptacles. That way they terminate independently and simply at the panel.

Does anyone know the fill limit for 3/4" conduit?

If you have 6 12 awg thhn wires you are fine.
In the code book it says you can have a max of 16 12 awg thhn in 3/4" EMT. I'd like to see how easy those pull.:D Good luck with running the conduit along the walls to each outlet box.

As for the outer seath on 12/2 It's there to protect the wires but conduit will do a much better.

[sparkync1]

here in nc we cannot pull "romex" through any conduit ..emt, pvc or any type of flex if it is terminated on both ends in some basements the inspectors are making us put up a board on a block wall like they did years ago and put each romex into the panel with a romex connector not using the 2 inch pvc like we used to do if this is your case and your flexible coundut will not be terminated at the panel then you can do it or at least you can here in nc have you considered wire mold it might be a little bit more attractive than any of those other options you are considering ??

[Rocky Mountain Sparky]

Okay just got some info from the elecrical inspector

PVC is against code to run indoors - I have to run steel conduit. I think PVC releases toxic gases if it melts during a fire.
That must be a Canada thing - PVC is used by plumbers extensively in the homes around here, and I don't believe it gasses any more or less than NM cable would in a fire. PVC is used by electricians when running through a slab and stubbing up for islands in kitchens of slab on grade houses.

NMC can't be run in any conduit if it has a sheath. It can't be run in conduit without a sheath, as the conductors are not marked appropriately for conduit use. The markings are on the sheath of the cable.

334.15 of the NEC actually requires romex to be installed in conduit if exposed to physical damage.

I would buy the right length of 12/3 romex with ground, fish it in the walls, and call it a day. Keep it simple. :)

[franklin pug]

The inspector told me to run individual #12 wires - which is what I did. NMC can get hot i guess. I connected the panel to a junction box with regular 12/2 NMC (though framing members). From the junction box I ran three individual #12 insulated wires (black, white, green) through EMT conduit to a GFCI receptacle, which in turn fed another.

[Pierre]

I cannot speak for Canada, as I am not familar with the code up north.

In the states, there are a couple of items of note.
In the 2002 NEC, during the code cycle change, there was an issue (not done on purpose) which restricted the installation of some cables inside of raceways. that has been resolved in the 2005 NEC. In the raceway Articles, there is a section, xxx.22 that will tell one whether or not a cable type is permitted to be installed in a raceway. In most instances, a cable is permitted installed in raceways.
As for PVC permitted indoors, there are also a couple of issues.
1. Check for local more restrictive codes.
2. Most types of PVC conduits are permitted indoors (HDPE is not one of the permitted PVC types permitted indoors).

If an inspector is asking for something that is not in the NEC, ask him if this is a local law and then ask for the section number so you can educate yourself. Then you will also find out if the inspector is up to snuff.;)

[proplumb]

pug you inspector is talking bullshit. ther is no place in the national plumbing building or electrical codes where it says pvc cant be used indoors. pvc is required on most commercial jobs due to its fire rating. you need to call again. i use pvc for wiring, plumbing, and condinsate lines.

[franklin pug]

Thsnks for the heads up proplumb, I'll call again if I need to run anymore conduit.

[rjniles]

I ran a 12-2 UF, 20 amp line to my shed. I used a short piece of EMT to protect the UF where it ran into the ground at the house and shed. Have I caused an issue with overheating in this circuit?

[JimDon]

No, that's a common practice with UF going into a trench. Just hope that you used a plastic bushing at the end of the 90 as it enters the trench.
Jim Don

[TheElectricalGuru]

Hello,
I have been reading the direction of this post and it needs to be made clear.

1) Yes, NM Cable can be installed in RNC if it is for protection and the claim could be used in most all cases for protection. Nothing in the NEC prevents NM Cable in RNC and this is specific in 352.22 and since 334 does not prevent it in RNC it is allowed.

Now....it boils down to can NM Cable be in conduit for just no reason.....no because the only allowance for not securing it at a box is unless for physical damage......so prove it is for physical damage and you dont need to secure it at either end.

2) While it is the allowed in the premise of (1) above....understand you could have issues with derating and conduit fill ahead of you.

Now.....if you are speaking of running it from a cabinet, cutout boxes, and meter socket enclosures to a junction box.....say in your garage....you will have to meet the requirements of 312.5(C) Ex. and it must be more than 18" but less than 10'..........and if over 24" dont forget ampacity adjustment factord of 310.15(B)(2)(a).