Situation:
I need to run #6 sized conductors to an outdoor subpanel which is attached to the same structure as the main SEP.
1-1/2″ PVC conduit is already trenched in and subpanel mounted.
Conduit terminates inside in a crawlspace – just a raw pipe end at the moment.
Will need to run cable / wire roughly 50′ across the crawlspace, into the basement to the SEP. Then another 15′ – 20′ to the outdoor subpanel.
Question:
I believe it is not legal to run Romex through conduit when the conduit run is underground. Yes, legal? No, not legal?
If “yes, legal” my question is answered – no need to read any more.
The easiest way to cross the basement and crawlspace would be with 6-3 w/ground Romex.
Assuming that Romex is not legal for an underground run in conduit, I would need to transition to single conductors Type THWN through the conduit to the outdoor subpanel.
I am thinking of making the Romex to THWN by using a panel box with a pull-out type disconnect – Romex in – THWN out in conduit to outdoor subpanel. I do not need the disconnect feature – just seems like a cheap, easy way to make the required splices.
Thoughts? Suggestions?
Thanks in advance.
Jim
Replies
You are right for the wrong reasons.
Underground conduit is a Wet Area. And romex is not rated for wet areas.
You can use UF cable or USE (underground service entrance cable).
But UF is really stiff. And USE can't be used inside, except long enough to terminate it into a box or another wiring system.
I am guessing that this is for a pool or spa of some sort. They have to be wired with an insulated ground wire and not bare copper. So that leaves out the UF.
So I think that running THWN is your best bet for the UG part. And depending on "everything" you can continue the conduit inside or connect to a different wiring system.
William the Geezer, the sequel to Billy the Kid - Shoe
Spa.
THWN it is for the underground.
Your opinion of using a pull-out disconect as a box to transition between Romex for inside and the THWN for the underground? Square D, 60 amp rated = $6.50
Just to clarify re: insulated ground wire. The THWN will be insulated and inside of the conduit to the subpanel.
Coming out of the subpanel (30A GFCI and 20A GFCI, 2 pole breakers) and running in PVC flex, the ground wire must be insulated - correct? This was my understanding, even before your post!
Thanks, I always value and trust your input.
JimNever underestimate the value of a sharp pencil or good light.
If I were you, I would continue the conduit across the crawl space and have a continuous run of wire from the outside panel to the inside panel.
PVC conduit is cheap and so is single strand wire (well, relatively cheap)
I would imagine running romex in a crawl space would be way easier than installing conduit and running wire through it.Somebody mentioned installing a disconnect box at the point that you go from romex to THNN. Why not just use a j-box and splice the two sets of wires at that point?A disconnect under the house in a crawl space sounds like overkill.
I would run the conduit. It gives you that extra protection from rodents etc, saves you the hassle of messing with a junction box ( I agree with you that a junction box is a much better idea than a disconnect switch) and eliminates a set of connections that possibly could go bad down the road, and lastly is probably cheaper than doing it the other way.
It's an easy DIY project. You can easily bend PVC conduit with a heat gun.
"Coming out of the subpanel (30A GFCI and 20A GFCI, 2 pole breakers) and running in PVC flex, the ground wire must be insulated - correct? This was my understanding, even before your post!"I am not really up on spa and pools.But it is my understanding that anything outside of the house has to have an insulated ground.But you can run NM-B or other systems that have a bare ground inside the house.About the disconnect. A little strange, but it should work.One caution. If you need a neutral there won't be a spot in the box for that and you will still need to splice it. Might not be enough room for that..
William the Geezer, the sequel to Billy the Kid - Shoe
Not sure about starting a whole other thread, so maybe Bill or someone could answer (please):
Am trenching a utility line (just got the gas line installed) where I am running an electrical service to a separate structure on the property (an existing pool house from the new house). I will have 1 1/4" conduit in the ground in which to pull my wires.
Couple questions:
1. In that 1 1/4" line/conduit that will come into a small breaker box of the pool house, can I go "back out" of the breaker box in the same conduit with some wire to service some exterior outlets/receptacles and pool pump shed (for filter pump) i.e. sharing the 1 1/4" conduit for all the wires?
2. And/or if the above is (not) possible and I decide to also run a small conduit out of the breaker box for the services outlined above, say with 1" conduit, can I share multiple circuits in the conduit? I was thinking maybe 2, 10A lines; one for the exterior outlets/receptacles and one for the pool pump shed?
Thanks!
"1. In that 1 1/4" line/conduit that will come into a small breaker box of the pool house, can I go "back out" of the breaker box in the same conduit with some wire to service some exterior outlets/receptacles and pool pump shed (for filter pump) i.e. sharing the 1 1/4" conduit for all the wires?"Electrically you can, if conduit fill is correct. But mechanically I don't know how you would do it.the conduit runs from the house to the pump house. How are you going to get the wires out of that conduit to to the receptacles.Or do you mean running additional circuits from the house to the pump house and than out the pump house to the new receptacles.That isn't legal. You can only have one circuit (service) to a structure. You can have some other control circuits, such as a 3-way lights between the two. But the idea is that if you kill the feeder breaker than you guarantee that there is no power in the outbuilding.The logical way to handle that would be to add the new circuits to the pump house sub-panel. Even if that means a new sub-panel. Probably cheaper anyway than running all of that copper..
William the Geezer, the sequel to Billy the Kid - Shoe
Thanks for that Bill. I may not have been so clear. I am going to go New House ------------> Pool House ------> Pump Shed I would be back tracking in the same trench from Pool House ------> Pump Shed with two circuits or lines (the actually circuit being in the break box at the Pool House) going for 1. landscape receptacles and 2. to power the filter (and probably a light) in the Pump Shed.
Electrically you can, if conduit fill is correct. But mechanically I don't know how you would do it.
the conduit runs from the house to the pump house. How are you going to get the wires out of that conduit to to the receptacles.
What I was thinking possibly "mechanically" was to install a T-Box (not sure the correct term) where when I come back from the Pool House to Pump Shed, I would then peel off with the additional circuit lines via two tees. So on the 1 1/4" line I would install tees with reducers down to like 3/4" to run those branch lines.
The reasoning basically for this "shared" configuration is that the conduit has to run outside the structure from where I come up from my trench. There is too much hardscape to get to the existing breaker box/sub panel underground all the way. So I was thinking the less conduit I had to attach to the building, the better.
If I follow you correctly that should work. Just to be clear that "t" needs to be accessable, IE above ground.But the problems are conduit fill.And derating. If the length of common conduit is more than 24" then you need to derate the wiring.If you have 4-6 equivalent current carrying condutors you need to derate to 80%. If 7-9 then to 70%.The feeder will be 120/240. That is 2 hots and neutral. There is only 2 equivalent current carrying conductors in that. If you have full load on 1 hot and neutral (120) then the other neutral has zero. If you have full 240 load then the neutral does not have any current.If you have two other independent circuits then you will have 4 more current carrying conductors for a total of 6.If you use THHN/THWN you can use the 75C column in the wire tables so you might not have a problem. But it depends on what size wire and feeder and branch circuits that you are using.BTW, the "t" is called a conduit body and you can get them with the 3 ports going in different directions compared to the cover.But you might want to look at a different option.You can get plastic boxes with no ports in them. Then drill out the holes and glue in nipples. (I not sure if that is what they are called. Basically a short piece of tubing with a flange on it.)That will give you a little more working room and you can make each port the size and direction that you need..
William the Geezer, the sequel to Billy the Kid - Shoe
Thanks again Bill. The "T" would be buried (funny, not only did the guy at Home Creepo say I could bury it--I mean it does have a gasket he said-- but he also suggested I run romex in it to boot!). I suppose they don't make a conduit body, T, without a cover, eh?
Anyway, I had thought about conduit fill and yeah, I will have a 120/240 feeder which should be fine for the 1 1/4" but may be getting a little "tighter" with the additional circuit wires. I didn't think to much about derating other than in the original plan of bringing down a feeder to the Pool House from the new house, we did account for that, but not really with additional wire in there. Not even sure what I wired from the new house's main panel to the near outside of the new house; need to look in the panel box again.
Probably cleaner to just run that second conduit on the exterior of the pool house and dump in the trench back out the same way the feeder came in and then branch out, hopefully finding a couple tees that can be buried. Thank you!
Underground conduit is a wet area anyway.I am not sure as I have never had to dig into this (all puns intended), but I think that any conduit you need to be able to access it to pull new wires and a buried conduit body would not allow that.But you could use a "handhole". That is the same as a manhole, but sized much for to get a hand in.But you need to bring it to the surface.But in all I think that running the separate conduit will end up being clearner in the long run..
William the Geezer, the sequel to Billy the Kid - Shoe
Years ago an electrician friend told me that the ground wire from swimming pool lights must be continous from the fixture to the panel. No junction boxes, splices, etc. Apparently it's code requirements.
Thanks for the info, but there are no lights.
Other question would be "Which panel?" Meaning if said lights had OCPD / GFCI protection at an outdoor subpanel in the vicinity of the pool - woud that count as a "panel" or is the reference only to the main SEP?
Jim
Never underestimate the value of a sharp pencil or good light.
Edited 1/4/2009 5:47 pm ET by JTC1
Lights, pumps, etc. anything electrical. Apparently the concern is anything electrical hooked up to pools, spas, etc. Don't want to lose the ground due to connections failing.
Sorry I can't confirm since my friend died years ago.
"Lights, pumps, etc. anything electrical. Apparently the concern is anything electrical hooked up to pools, spas, etc. Don't want to lose the ground due to connections failing."It would be to a common point. If you have a pool house with a sub-panel it would be there.The critical thing in pools is BONDING. ANY AND ALL METAL HAS TO BE BONDED TOGETHER SO. That includes things like ladders and rebar.Anyone interested in more details for pools, they can start here.http://tinyurl.com/78qeqvBut it is based on the 1999 NEC and it is not easy to read. And neither is the code..
William the Geezer, the sequel to Billy the Kid - Shoe