*
O.K., this may be in the “dumb” catagory, but conider the source:
Can you run a #2 3 wire (plus ground) romex style (or UF) underground through a conduit??? Or do the wires get too hot? Through conduit, do the wires need to be separate for cooling purposes or does the NEC allow a romex style cable to be run through? Good god almighty, I caint write today…hope this makes sense…
Newman
Replies
*
Yes, you can do that. It is routine when UF comes out of hte ground and goes up to a meter box or into a building. And yes, where the conductors are run effects their amp rating.
There are tables in NEC for different variations such as "Ampacities of Insulated Conductors Rated 0-2000 volts, 60 to 90C (140 to 194F), Not more than Three Conductors in Raceway or Cable or Earth (Directly Buried) Based on Ambient Termperature of 30C (86F)" It has 8 different columns with 40 different types / temperature rating. (e.g. THHW 75C, THHW 90C, THHN 90C, etc.)
And others at different temperatures and in different situations (number of wires, free air, etc). In the example given above, the ampaities of 2 AWG copper, UF 60C is 95 amps. And for 2 AWG aluminium, UF 60C is 75 C. So a current-limiting device (fuse or circuit breaker) of that amperage or smaller must be feeding the conductors. Breakers downstream of the cable can, surprisingly, be larger. So a 100-amp main breaker in a load distribution center (a.k.a breaker panel) would be okay to be fed by such cable.
So go to the library and check which table is closest to what you are doing. Or maybe somebody here has got a copy they can check for you.
*David,Thanks for the reply--What I am planning on doing is running a 100 amp sub panel to my detached garage...The wire will run about 45 feet in the crawl space of my house into conduit (which I just found out I will need to trench)for about 26 then travel about another 25 feet in stud walls to the sub panel. The garage is being set up for wood working with about 3 240 machines (only run 1 at a time).While I thought I had existing conduit to fish a new line, it turns out that the old line was buried...so I will now need to trench...So I thought I would run one line from the main through the conduit, through the stud walls, to the sub panel (i.e. no junction box headaches). Does this sound like a plan or am I missing something? Should I use UF or basic romex?Thanks--Newman.
*WTF....!?....Get thee subpanel 4 wire...Not SE or Romex.Run it in conduit the entire path.near the stream,aj
*Why would pay extra for this stuff? Terminate the romex at a junction box on the outside of the home. Go down and across and up with conduit and #4 (or whatever diameter is appropriate for the load and length. Terminate it at a box on the shop wall, and continue with your Romex. That stuff is harder to pull and is about double in expense. Run a second piece of conduit and put in a pull tape for shits and grins.I don't know about you, but any length of #4 over about 25 feet is a b*tch to pull, lubricant or not. Romex is so stiff, I can't imagine trying to pull it down, across and up over any length. You'd have to hire a team of mules.
*AJ,Thanks for the reply...O.K., I'm getting conflicting information...Some electricians are telling me that I can't run an enclosed wire like Romex in 26 feet of conduit because it heat's up too much...As to subpanel 4 wire--here comes more dumb questions...this is a special wire specifically for subpanels??? How is it different from Romex? More flexible, etc. If it is made for subpanels....well that seems to be the ticket since that's what I'm doing. (BTW-I'm only running the wire, an electrician is going to hook it up. The problem is figuring out the best way to do it and meeting code...)Thanks,Newman.
*Scooter-Meister,I had thought about the junction box, but how the hell do you junction two #2 wires??? That's one hell of a wire nut :-)!I had NOT planned on actually "pulling" the wire, but building the conduit piece by piece on the wire...if you know what I mean.Another electrician suggested using Romex, then stripping the cover off that section that will be in conduit...This would prevent overheating in the 26 feet of conduit and allow it bend more readily through some of the corners...What do you think?
*> I had thought about the junction box, but how the hell do you junction two #2 wires??? That's one hell of a wire nut :-)! For wire that big, you use either split bolts or other large-guage connectors, and wrap them with vinyl tape. Use big junction boxes (the weatherproof PVC type where you drill your own holes work pretty well).If local inspectors allow, type UF can be direct-buried without conduit. If not, use separate wires in non-metallic conduit. Don't use type NM (Romex), even in conduit its paper core doesn't belong underground. For only 25 ft., if you use conduit do yourself a favor and run a big diameter for an easy pull.
*Newman,As a humble DIY'er here's my opinion, for what it's worth.I think you are thinking way to much. In my opinion you should ask the electrician who is going to be making the connections a lot of these questions.Because:1. He knows what your local inspectors will accept.2. He will be doing work and he will tell you what is acceptable to him.3. You stated that you were thinking of laying the wire in the conduit as you go. If I remember from a previous discussion on this topic this may be frowned on by certain inspectors. It would be a major league bitch to have to pull all of the wire out.4. Maybe I'm missing something but why don't you want to run conduit from panel to panel? It seems to me that this would be the professional way to do it, but then again I'm just a amateur looking in.
*Another unuseable Electricution thread....near the armchair wizards playing with death in the e stream,aj
*Whatever you do, don't put Romex in a conduit!fv
*
O.K., this may be in the "dumb" catagory, but conider the source:
Can you run a #2 3 wire (plus ground) romex style (or UF) underground through a conduit??? Or do the wires get too hot? Through conduit, do the wires need to be separate for cooling purposes or does the NEC allow a romex style cable to be run through? Good god almighty, I caint write today...hope this makes sense...
Newman