Can you use “stripped” romex in conduit
Hi,
So far so good on my whole house remodeling. I passed inspection on the third floor but would have like a more rigorous inspection! That said, I have two questions:
1) Is it ok to use romex wires stripped of their outer (yellow) jacket as the conductors within ENT or the plastic equivalent? Or is it better to purchase the separate conductors? It seems as though the jacket is more durable but I am not sure of that. Speaking of conduit any preference for metal vs plastic?
2) I know this question has been touched on before but I wasn’t 100% clear as to the conclusion. Is it ok to have multiple 20A rated outlets on 20A circuit? I understand the logic behind having multiple 15A rated outlets on a 20A circuit but unclear whether this logic extends to 20A rated outlets.
Many thanks,
John
Replies
John,
1. if the conductors (wires) in the cabe are designed and UL-listed to be used as free conductors in conduit, yes you can. How do you tell? The individual wires will have marking on then, describing the type of insulation (typically, THHN). If the wire is marked THHN/THWN, or some other standard designation, it signifies that the wire is O.K. for use in conduit.
The catch is, common NM cable is not made with wires so identified. Even if the insulation was the same as that on free THHN conductors, it'd cost more to label the individual conductors and get them UL-listed. So there no reason for the cable manufacturers to do it.
My suggestion: just go buy some THHN wire and pull it in the pipe. Use a junction box to make the transition between the romex and the free wire.
Metal vs plastic conduit? Depends on the application. Plastic is better underground, or in wet or corrosive areas (like a barn) where it's not exposed to severe physical assault. Metal is better in any other instance, but costs more and takes more time and skill to install. EMT (thinwall conduit) is a good tardeoff between the durability of medium wall (IMC) and the ease of installation of greenfield (flex or flexible metal conduit). GRC (galv rigid conduit) is not used much outside of govt buildings and industrial settings. It's expensive and hard to bend.
2. You can put as many 20A receptacles as you want on a 20A circuit, in residential occupancies at least. The question is, why would anyone want to? There are very few tools or appliances that require a 20A receptacle, and 15A receptacles can be had that are just as robust and durable as the 20A ones. That's the main reason people want 20A recepts--durability, strong grip, etc. Just get a commercial or even spec grade duplex 15A recept and save a little $ over the 20A one.
The only time Code requires a 20A receptacle on a 20 A circuit is when the circuit has only one receptacle on it--that's a simplex (single) receptacle, not one duplex receptacle. One duplex 15A receptacle on a 20A circuit is fine.
You can't put any 20A receptacles on a 15A circuit.
Good luck,
Cliff
"You can put as many 20A receptacles as you want on a 20A circuit, in residential occupancies at least."
No, you can't. The NEC limits the number of receptacles that can be on a circuit and/or it limits the number of "openings" that can be in a single circuit.
No, you can't. The NEC limits the number of receptacles that can be on a circuit and/or it limits the number of "openings" that can be in a single circuit.
Where does it say that? that would be news to me. ;)
I agree with you...I don't believe you can run as many 20A receps on a 20A circuit. I could be mistaken but I believe there is a limitation, can't recall exactly.
Tim,
You're mistaken. Can you cite the NEC section(s) that lead you to think there's a limit on the number of receptacles in a branch circuit?
There aren't any; there is no limit in the NEC on the number of receptacles on a circuit, for residential occupancies. Some local Codes do have limits, though.
In the NEC, there is a requirement for different occupancies laid out in the load calculations for the service size as to the number of volt-amps to be provided for lighting and convenience circuits; for houses, it's 3 VA/sf, and this can then be translated to a required number of lighting/convenience receptacle branch circuits.
But the NEC has no specific requirements or limits on the number of receptacles allowed on a branch circuit. Most of the time the outlets are generally evenly distributed among the general lighting circuits. But there's no requirement to do so. It'd be bad design to have 33 outlets on one circuit and 2 on another, unless there was a good reason to, but the NEC is not a design manual and generally doesn't address this kind of thing.
There is an NEC requirement that the circuit be sized to support the expected loads, but for receptacle outlets on residential general lighting circuits, there is no prescribed load per receptacle (or lighting) outlet.
On the other hand, in commercial occupancies, the NEC requires one to use the actual or expected load on a receptacle outlet when sizing circuits, and if that's unknown, to assume 180 VA per receptacle. This requirement does limit the number of receptacles on a circuit, in a commercial occupancy. But that's not what the OP is dealing with, and this is a board about homebuilding.
I'm not saying that a person should put an unlimited number of receptacles on a circuit; that's a design issue. Factors like the expected use of the outlets and cost and cost-effectiveness come into play. What I'm saying is that the NEC doesn't have specific requirements limiting the number of receptacles on a branch circuit in a house.
Cliff
Re: number of outlets on a circuitYou're right, at least according to an electrician I consulted not so long ago about this issue. He told me there is no specific limit on residential work.But I seem to recall he said the NEC sets a limit of 8 outlets on a circuit for commercial work. It seems stupid to me, but theoretically you could put 50 outlets on a circuit according to the NEC.However, I wonder if local jurisdictions ever place limits on the number of outlets per circuit?********************************************************
"It is what we learn after we think we know it all, that counts."
John Wooden 1910-
"I seem to recall he said the NEC sets a limit of 8 outlets on a circuit for commercial work."
As CAP mentioned, for commercial work you assume 180VA per receptacle if the loads aren't known. 8 x 180 = 1440va, 1440/120=15 amps. So, for a 15 amp circuit he's basically right although the NEC doesn't exactly say it that way.
Local jurisdictions do sometimes have limitations on the number of receptacles/circuit for residential work; I imagine they probably do for commercial work as well, but I haven't run into it here in the Twin Cities area.
The question is, why would anyone want to? There are very few tools or appliances that require a 20A receptacle,
What drives me nuts are the tools (and there are alot of them) that state in the manual, "this tool must be used on a circuit with a 20A breaker", and they come with a 15A plug!
If they shipped with a 20A plug, then they could be ensured that they would only be used on 20A branches. Of course they don't because most 20A residential branches don't have 20A receptacles.
Personally, I'd like to see a code change to eliminate the use of 15A receptacles on 20A branches. Over time, that would remove the tool manufacturer incentive to use 15A plugs.
I have yet to see any device with an actual 20amp plug on it. I'm sure the exist, but even the washing machine (which is supposed to have a 20 amp outlet) doesn't have a 20 amp plug.
we have a treadmill with a 20A plug as well as a toaster (4 slice/2bread-2 bagel) at work - so "they" are out there, just not very common
I saw one on a window shaker A/C once. Probably dumpstered by now.
-- J.S.
" I'm sure the exist, but even the washing machine (which is supposed to have a 20 amp outlet) "No it is suppose to be on a 20 amp circuit. Says nothing about the receptacle. Now, as already stated, a 20 amp circuit can have 15 amp receptacles if there more than one receptacle on the circuit.The type of plug is based on the load (washing machine) and I suspect that most are in the 8-10 amp range.
Regardless of the lack of markings, you can use individual NM conductors in conduit with the sheathing removed.
Otherwise one could never use bare copper.
---
I agree there is no limit to the number of recepts allowed on a residential circuit.
I don't understand. Why would anyone want bare copper in EMT?+++++++++++++++++++++++++++++++++++++"Doubt is not a pleasant condition, but certainty is absurd." Voltaire
To keep someone from getting shocked by it, obviously.
If Tyranny and Oppression come to this land, it will be in the guise of fighting a foreign enemy. --James Madison
In Colorado an EMT installation is the ground. I'm not an electrician, but I installed EMT in my shop and it was inspected and passed with no bare wire. I just had flex metal sheathed wiring installed by a licensed master, same deal.???+++++++++++++++++++++++++++++++++++++"Doubt is not a pleasant condition, but certainty is absurd." Voltaire
Wow,
What a response! As regards why I would want to strip romex the answer is that I do have a bunch left over from wiring the rest of the house. As for the 20A outlets, a friend gave me 2 boxes of Hubbell 20A receptacles. If I didn't have these I would 15A receptacles. Given everyone's advice I think I will ask my inspector what his feeling is on the unstripped romex in the conduit . I'll cite the code as recommended and I'll go that way if he is ok with it. I will also use the 20A receptacles in a few circuits in the basement. One other question - does anyone have experience/recommendations as regards LED lighting? I want to put new lighting in the basement and there is currently pretty old can lighting installed. I took at look at American Permlight's website and their stuff seems good. Kind of expensive though but I think they will pay for themselves in the long term. Many thanks!
John
Re LED lights, you're probably just as well off with compact fluorescent -- not quite as efficient and long-lived, but close enough, and a lot cheaper with more options to choose from
If Tyranny and Oppression come to this land, it will be in the guise of fighting a foreign enemy. --James Madison
The compact flourescent bulbs put out more lumens per watt than LEDs do - so far, and are a lot cheaper.
LEDs make better spot lights, CFLs make better area lighting.
The CFLs might not work in some can lights due to heat problems.
The question of markings being needed on the wire is important. Yes, obviously the bare ground wire is the exception - but for the rest of the wires it needs to be readily apparent what temprature the insulation is rated for. This is important to know how many wires you can put in that piece of conduit.Rebuilding my home in Cypress, CA
Also a CRX fanatic!
"Otherwise one could never use bare copper."Bare copper usage is limited to EGC's. Not current carrying conductors.Without the markings how can use show what the insulation is and thus the tempature ratings for calcualted the ampactiy of the circuit.
"Bare copper usage is limited to EGC's. Not current carrying conductors."What makes you think that the wire is copper and not just some wire that looks like copper? Usually the fact that the empty spool is lying aroung is sufficient."Without the markings how can use show what the insulation is and thus the tempature ratings for calculated the ampactiy of the circuit."The box is marked NM. That makes the individual conductors 90 degrees.---
So 5 years from now, when I buy this guys house, and I go to run another wire down this conduit... what - is it safe?
What if I go to any random house, not knowing the previous owner or workmanship. I just have some wire in conduit - is it OK or is it not? Who knows?
It's not like it could heat up and burst into flames. Oh wait - yes it could!Rebuilding my home in Cypress, CA
Also a CRX fanatic!
"The box is marked NM. That makes the individual conductors 90 degrees."Actually if the box is marked NM then they are 60 degree insulation.While you might know what the wire is the inspector has no way of know.
It is not my obligation to satisfy an inspector who makes outragous demands.(The NM cable sold near me is 90 degree.)
What's sold now is NMR.
If Tyranny and Oppression come to this land, it will be in the guise of fighting a foreign enemy. --James Madison
Whatever
If it is NM cable it is very, very, old stock and it is rated for 60.Show me a picture of the box that says otherwise.
You can run the romex conductor wire in conduit but why would you want to?
Unless it is just a short run or you already own a lot of romex it is not really smart to do so. Three THHN wires should run cheaper than the same length of romex and who wants to sit and strip the jacket off any length of romex.
As for conduit I generally end up using rigid PVC in residential because it is easy and cheap.
-day
Here's a real good case for running stripped romex in conduit. You've wired your own house with romex and still have 100' or more leftover and you bought it back when it cost about 1/2 of any copper wire today...now you're getting down to wiring a few extra outlets in your garage/shop that you're going to run in conduit.
It's really not hard to strip...just run out 20' or so, or however much you need, then tale a utility knife with a new blade and strip away...have to be careful you don't knick the actual conductor insulation.
Why strip the jacket and run the risk of nicking the insulation ? Just pull the whole NM cable in the conduit.
And just to head off those who overheard in the men's room that this isn't legal, it is specifically allowed by the NEC in Chapter 9, Table 1, Note 9.
If I measured and did the math correctly, the cross-sectional area of your 12 AWG romex is .15 square inches, so you can use half inch EMT (or anything larger) for one cable.
Just that it makes it easier to pull through a 90° if the jacket is stripped off....but thanks for the tip and code reference.
That settles that!
Yeah, that's what I kind of thought the case was and I must admit to having done the same thing myself in a pinch.
In reality I use enough wire that what I have left over from one house just gets moved to the next house getting flipped. I must have 1500' of different types of wire sitting in a jobbox in my garage right now, it gets used quicker than I realize on a rewire though and keeps me working and out of the car and Blowes.