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Junction box question

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billconner

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Extending a sub panel feed across an attic I'll insulate. Local inspector says junction box has to be above loose fill insulation. 1" pvc conduit, and I'll elbow up to a box, and back down to continue across lower chords of trusses. 2 hots, neutral, and a ground, all #6, all spliced in the box. I think minimum 30 c.i. but I always like more room. I can't seem to find a PVC junction box. Should I be able to find one or should I just but metal? If metal, dose the pigtail to ground box have to be #6?

Thanks in advance!
 
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mike93lx

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These are stocked around me

www.homedepot.com

Carlon 6 in. x 6 in. x 4 in. Gray PVC Junction Box E987RR - The Home Depot

The Junction Box is UL listed with a NEMA 6P rating per Section 314.29, Exception of the NEC. The box is made with a thermoplastic material and features a gasket lid attached with stainless-steel screws.
www.homedepot.com

I can't say I have always kept junctions above the insulation, but if it's getting inspected, you are stuck. I'm sure he would argue that buried isn't "accessible".
 
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mike93lx

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Yeah, I knew what you meant. I've never seen a marker like that and I expect it would be argued that it could be easily removed/damaged.

You'll have to pull back the existing wire to glue up the elbows and fittings. Sounds like a PIA
 
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billconner

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I've never used plastic conduit. I have used a lot of PVC for plumbing. Isn't it pretty similar? Thought I could do one coupling with wires in conduit. Only 20' and 2 bends if I have to pull it back 6'.

Could pull it and replace with new and not bother with junction box. 80' of #6 thhn.
 
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mike93lx

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Same process as plumbing.you just have to complete the conduit run before putting wire in since the glue melts insulation. 80 ft x4 of thhn won't be cheap
 
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billconner

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20' times 4 - so $80 or so, and avoid some conduit, fittings, and a box - so maybe a little less - especially since I have to add near 40' x 4. A single 250' roll should do whole run.

Thinking out loud........
 
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mike93lx

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billconner said:
20' times 4 - so $80 or so, and avoid some conduit, fittings, and a box - so maybe a little less - especially since I have to add near 40' x 4. A single 250' roll should do whole run.

Thinking out loud........
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Ah, that's a lot better. For 20', I wouldn't deal with splicing at all

You need green, white and then can use the same color for the other two, just not white, green or Grey.

I bought copper xhhw by the foot at wireandcableyourway.com recently. Cheapest option when not buying full spools
 
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Norcal

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For 6 AWG the grounding conductor only needs to be a green 10 AWG, the neutral needs to have white insulation, tape is not permitted for 6 AWG & smaller conductors. a 4 11/16 square metal box would work quite well.
 
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billconner

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All 4 of existing are black, with three marked with green, red, and white tape. I hoped to continue in that way. I'll check with inspector. He's very fair and reasonable. I think I could replace it all with a 250 ft roll. Cost goes up a lot if cut pieces or 4 100' rolls.
 
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mike93lx

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If he is making you put the box above blown in, I bet there is no chance he let's you violate code on wire marking.
 
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Norcal

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billconner said:
All 4 of existing are black, with three marked with green, red, and white tape. I hoped to continue in that way. I'll check with inspector. He's very fair and reasonable. I think I could replace it all with a 250 ft roll. Cost goes up a lot if cut pieces or 4 100' rolls.
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If 6 AWG & smaller it does not meet code, I would leave it just don't continue the non compliant work, grounded & grounding conductors have have the properly colored insulation.
 
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billconner

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I get the ground, but hard not to use white for a hot in 3-way switch leg with Romex.

Since existing feeder is 4 black #6s, not crazy about extending ground with a green #10.

I'd originally planned a new feed in SEC from main panel - #2 for 90 amps - to a jb from where it's rigid underground to new garage. Then thought why not just reuse panel (from existing attached garage I'm turning into living space) and continue existing 50 amp feed (now in plastic conduit) to new detached garage. Probably should spend a little more, replace wire, and not have junction box in attic.
 
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mike93lx

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billconner said:
I get the ground, but hard not to use white for a hot in 3-way switch leg with Romex.

Since existing feeder is 4 black #6s, not crazy about extending ground with a green #10.

I'd originally planned a new feed in SEC from main panel - #2 for 90 amps - to a jb from where it's rigid underground to new garage. Then thought why not just reuse panel (from existing attached garage I'm turning into living space) and continue existing 50 amp feed (now in plastic conduit) to new detached garage. Probably should spend a little more, replace wire, and not have junction box in attic.
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White is fine for a hot in a cable assembly like nm-b. It's different when using individual conductors
 
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PCustoms

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Build a plywood box around the junction.

**** all insulation out.

When inspector leaves fill the box with fiberglass or foam sheet insulation and mark it.

Pretty sure all modular homes are built with junction boxes in the attic like yours.
 
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sparky 1971

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The inspectors I deal will let us mark #8 and #6. Some know it's a load of **** and no more "dangerous" than marking #4 and larger while the others are do it all inspectors that don't even know that rule exists.
 
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Norcal

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sparky 1971 said:
The inspectors I deal will let us mark #8 and #6. Some know it's a load of **** and no more "dangerous" than marking #4 and larger while the others are do it all inspectors that don't even know that rule exists.
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If they are marked correctly it's not unsafe, just not code compliant.
 
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dscheidt

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wyliesdiesels said:
Ive never understood that code (cant tape #6 and smaller)…
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My guess it's because that work is more homeowners and handyman types would do, bigger stuff is going rto be done by someone who knows what they're doing. The code has a fair amount of protect idiots from themselves in it.
 
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billconner

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Measured more carefully. Existing run is around 42' and new run will be around 90'. Seems simple to just replace wire, reuse conduit, and avoid JB and splice in attic. Could yet change my mind.

@mike93lx - an idea of shipping and handling at wireandcableyourway.com? Thanks.
 
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mike93lx

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billconner said:
Measured more carefully. Existing run is around 42' and new run will be around 90'. Seems simple to just replace wire, reuse conduit, and avoid JB and splice in attic. Could yet change my mind.

@mike93lx - an idea of shipping and handling at wireandcableyourway.com? Thanks.
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They aren't cheap...I paid $27 to ship 4x113' pieces of #10 thwn. That said, it was the cheapest option since I had no use for full rolls. If I could have used sizes that were available in roll lengths, I bet HD would have been cheapest.

I would strongly recommend getting the conduit in place, **** through a piece of Mason line, pull that out and measure. I did that, added 3 feet and cut off 3 feet when I installed the wire
 
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billconner

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Thanks Mike. Sort of what I guessed. If I put in all new it's near three 100 ft rolls and wouldn't be much different than local.

I'll probably wait till I can pull a tape through conduit and get exact.
 
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billconner

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Doing demo around the area before I do electrical, and have arrived at cutting PVC conduit and adding a junction box, elevated, and leaving existing 4 no. 6s all black with tape; continuing from there with 6-6-6-6 SER to exterior junction box (put in last year with hurried rigid metal conduit to new garage); and splice there with white, red, and black thhn/thwn to relocated panel in new garage. Use rigid for ground (and there is an ufer). Not especially proud but basically complies with code and lowest cost and lowest labor.

Any reason not to use wire nuts in junction boxes? I could go to insulated crimps. The screw type seem crazily expensive.
 
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wyliesdiesels

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Not quite clear here. Does the SER run underground?

Also, you dont need #6 for the EGC. What size breaker is feeding this?
 
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billconner

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No. SER runs across attic joists, doen through exterior wall, and into a NEMA R3 jb mounted on exterior wall. From there I have rigid metal, some underground, to detached building.

50 amp 2 pole in existing panel (feed) as well as planning to reuse sub panel with a 50 main.

Existing is 4 no. 6s. The SER I found (https://www.wireandcableyourway.com/6-6-6-6-copper-ser-service-entrance-cable) on Mike's suggested site) was 6-6-6-6.

Need about 20' of SER and 20' of thhn/thwn in rigid.

I think you're suggesting I find 6-6-6-10 SER. I guess I could. I don't think it's required by code.
 
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billconner

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Since more than half of the almost 100' run is no. 6 copper, I think I'll stick to it. I'll ask inspector if I can go to a 60 amp breaker, since 50 was a compromise to save money by reusing existing panel and wiring.

I also can't find no. 8 cu SER anyplace and since it will be exposed to exterior for a short run, I think it has to be SER.

And don't google this question. Overwhelmingly the answer for a 50 amp sub panel feed is no. 6 cu or 4 al.
 
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