Another Construction Question: 220v Wiring
 

This forum is the best as I get all kinds of info here from the brain trust as well as seeing other people's projects for comparison.

I'm moving my oven from one wall to another. I need to move the 220v outlet which I did last weekend. I replaced the original 220v wiring with new wire which spans about 25' from the circuit breaker to the outlet. Basically, I am keeping exactly what I had but just moving to a different area an using new wiring.

My Question: This wiring is run under the house and I put in flexible metal conduit. Someone at work told me that I might not use conduit due to heat generation of the wiring - Can anyone tell me the best practice or code for this. I used large 1.5" flexible metal conduit. The original wiring was in 3/4" flexible conduit but the original wiring was single strand and the new wiring is incased so that all 3+ground is contained (similar to romex but for 220v (actually 600v)). I used the larger conduit simply because I had it and it was a good thing as it was a pain to feed thru it; I would never have gotten it into the smaller conduit.

Any advice would be appreciated.

The heat is determined by the wire size and the current. And the routing means is determined by code.

What size wire did you run?

I think you are probably 100% fine for safety...not sure about code. Did you run 'liqui-tite' conduit with proper fittings at each end? How is it secured to the house?

You wired from the breaker to the new box, right? Not an extension from the old box?

Is the underside of the house 'exterior' or 'basement'?

A pic might be good.

3 wire Romex is rated @ 60 Centigrade (!40 degrees F)
Your house isn't going to burn down the NEC is your friend

60C is easy to hit on a hot day with undersized wire...which is probably not the case here.

Can't put Romex in conduit around here, code. If it is Romex, just secure it to the side of the floor joist and come up the wall, done.

http://forums.pelicanparts.com/uploa...1619111053.jpg

It's not romex. I was saying it's encased like romex - basically a black wrapping around all three wires + ground. Vs single strand (unwrapped) like the original). I don't remember all the specifics but definately remember seeing 600v stamped on the sheathing.

Exactly, conduit is for single strand wiring and if running Romex or equivalent cabling, putting that into conduit creates additional de-rating of the amperage carrying capacity due to heat build up.

If you have cable, ditch the conduit.

I work around electrical inspectors. They will not pass anything that does not follow NEC to the letter. If a cable has not been UL tested and approved to be placed in conduit, then doing so would be inconsistent with code.

I dunno about Vern's black-sheathed cable, but I would guess it is like a black style of Romex. NM rated. If so, then you just staple it to the floor joists. They like to see neat workmanship, BTW.

Thanks All.

My OCD will guarantee neat workmanship (once completed).

He probably has SO or SOW cord. Does it look like this?

https://cdn10.bigcommerce.com/s-9k6q...0.1280.jpg?c=2

I expect as much, Vern. If nothing else, I can tell by your name. Vern.

Don't mess around with anything else. Go get a length of Romex and use that. Find out the amperage required by the new oven and get the correct wire size accordingly. Its still cheaper then having something that wouldn't pass code and if it burns or cause any issues, you will be one responsible. Its not worth it. This isn't getting inspected?

^^^ Or pull individual conductors through the conduit.

I was going to say, you could always strip the sheathing and pull it as separate wires.

Noooooo. Don't use that wire. Throw that wire in the trash or use it an an extension cord. Get the required wire by code. normally it is the THHN wire that's needed in conduit. They should have tons at Home Depot or your electrical supply house.

I do NOT think Vern is trying to cut any corners here. I think he is asking these questions because he wants to do this right.

What I do n these situations is ask a friendly electrican what is correct and code, then I do the dogs body work of running the cable etc. then get the electrican to inspect and OK it. Minimal dollars.

Around here electricans like their work but don't like crawling around under floors of drilling holes through old timber.

Those wires will not have the appropriate rating. THEW , THHN something like that is correct.

Easiest way is a new wire, no conduit.

Cheapest way is to pull a new red, black, white, and green single conductor.

I know he's not. he maybe trying to use what he has lying around. Timber or s piece of steel, its fine but not wires. It must be correct type. Not worth saving a trip to the hardware store or 90 bucks of wires.

I hear what everyone is saying and I will submit a photo of the codes on the wires (tonight, after my day job).

Yes, I am using what I have laying around however, it is the wire that was recommended by my electrician when installing 220v for my dryer. I purchased a 100' spool which was about $300 and I am using the remaining for my stove/oven. Regardless, I will report back on the exact specifications. The wire is not Romex, I merely used romex as an example as this is very thick individual strands that are encased in a black wrap which states 600v plus a bunch of other stuff.

My primary question was about the conduit as I thought that would be the safest until our plant engineer told me he didn't think I should be doing that. However, on all of my projects, I want to follow the proper code. I have a friend that is a contractor that will be coming over this weekend to review my work.

Romex will sweat inside conduit.

You appear to to have 6/3 romex inserted into fmc.
The potential for heat generation is minimal.
Two 180* phases with a neutral and a ground will offset and cancel. It's not like you are running a single conductor in an enclosed space.
You went over and above sleeving in the fmc, worried about potential damage from rodents and whatnot, but i hope you at least put a bushing on both ends of the conduit.

On the fuse box end, there is a solid 1" heavy conduit that comes out of the circuit breaker box downwards and then curves into the foundation (about 5' total) of the house and ends. This is something that must stay as it is cemented into the house.

After that, my flexible conduit is connected via a threaded connection to the permanent fuse box pipe.

The flexible conduit is then routed to it's final destination and strapped to the bottom of the 4x6 floor joists under the house. The flexible conduit is then routed up and thru the wall to it's final destination.

I will take photos of the wiring tonight to help determine if it needs to be inside conduit or not. We'll go from there. My only regret is that I'm gonna have to crawl under the house again - I too old for this S#!T :)

If you do it right, it's an ab workout.

You'd think that over-designing the installation would get you a pat on the back. Using the proper non-conduit cable, and then protecting it in conduit. Makes sense, but the inspector may very possibly fail it. I knew of one installation which the inspectors failed, causing the builder to start over. It was "direct burial" cable, perfectly suited for just burying (at the proper depth). Builder pulled it through conduit for extra protection. Fail.

Who knew? Electrical inspectors are persnickety.

Small tangent:
"Not basement but a crawl space"

What kind of ventilation is going through the foundation there?
Critters will get in and make a home i.e. poop if they can.

Is the underside of the crawl space going to be vapor-barrier sealed from ground or below the joists?
That space where the wire runs through might be considered 'exterior' to code and might require different specs.
IDK.

As a layman, my first thought is a sealed full floor wrap up to the rim/floor joists to prevent ground radon/moisture/fumes from getting into the house.

(sorry for tangent just some random thoughts)

Yep, just run the bundled wire exposed stapled to the underside of the joists,
Enclosing it in conduit could cause condensation and is not code approved.
Only single strand wire is allowed in conduit

He already said it's not Romex, I am guessing SOW now.

We aren't debating 'safe' any more, it's to code, or not to code. And my guess is it's not.

The "other stuff" should include the wire gauge, which is VERY important.
Look at the oven and see how many amps it draws. I'm sure some of the experts here can take that information and calculate what gauge you need for that length of run.
For a crawl space I would critter-proof the system with new individual wires run through your conduit.

Update:

The code on the wiring is as follows:
Romex (R) Simpull (7M) AWG 6 CU7 CDR With AC 10 Ground Type NM-B 600 Volts

I was incorrect on my previous comments on Romex. My thinking was that this wire is not like common household outlet wiring (i.e., Romex).

http://forums.pelicanparts.com/uploa...1619194929.jpg

http://forums.pelicanparts.com/uploa...1619194971.jpg

http://forums.pelicanparts.com/uploa...1619195022.jpg

Since it's not exterior I believe you can run that direct.

Someone from CA should confirm it meets your code.

Yep. Can't be exposed to light. As long s its under the house and run in-wall, you will be fine. 6 gauge, that's a big puppy. How many amps does this oven draw?

6 awg is a 50 amp circuit

Thinking that NM cable cannot be placed in conduit is one of the most perpetrated falsehoods in the electrical trade. In fact, under certain circumstances where damage is imminent, it is required.

However, the issue is conduit wire fill. I didn't look it up but 6/3 with ground in 1.5" conduit should meet wire fill requirements. (In fact, I did look it up, but not in the NEC. Says wire fill must not exceed 53%)

One thing against pulling NM, NMC and NMS cables in any conduit is the pull itself. I would pull the cable into the conduit outside while the conduit ls laid out straight and clamped. Of course I would have determined the needed length first and left a foot of extra cable out at each end for make up.

There are not many cables that cannot be in conduit unless it's buried (wet location). And NM (Romex) is definitely one of those. that can't be used in wet locations. For that you need individual wires rated THWN. In fact MHF (mobile home feeder used a lot for direct burial between buildings) MUST be in conduit once above ground. It is terminated in a panel located as close to the riser as possible and still meet location requirements. (That was just an example for dispelling the myth.)

Note to the above: when determining wire fill one must measure the widest part of a wire bundle to calculate area by using a pi formula either by radius or diameter to determine the area in a circle form even if the cross section of the cable is not a circle. In the case of 12/2 Romex with ground, that's about 1/2" on the flat side so no way will 1/2" conduit be large enough. 3/4 does that job.

334.15 (C), you’re good