# underground service wiring conundrum



## RustyShackleford (Jun 17, 2018)

I'm trying to run 30-amp/240v electrical service to my shed, maybe 60ft.   I bought a 100ft roll of 10-3 UF-B awhile back.   But today I tried to dig the trench and it was all I could do to get 18" deep (instead of 24" required).   So I've gotta do PVC conduit.   I'm wondering if I should return the UF-B and buy THHW; it'll be about a wash in cost but a bit of a hassle.   I'm worried about trying to pull the UF-B, especially since there's a 90-degree bend midway (maybe I can smooth it out to two 45s).   Speaking of pulling, what size conduit should I run ?    Also, reading the NEC, it looks like I can go to 35 amp service if I use THHW (instead of 30 amps for the UF-B)


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## Ashful (Jun 17, 2018)

Pulling UF-B thru conduit can be a bear, if favor THHN.  In overhead conduit, I use what’s called a “pulling elbow” or an outlet body (eg. Type LB), when I need to install a 90 elbow, but you’d have to check to see if they’re rated for burial.

I can look in my book tonight for minimum conduit size, but have you de-rated your conductors for distance, if over 100 feet total from breaker to load?  There is margin in the 10/30 combo, so the derating is likely nil for up to 150 feet, but I’d have to look that up to be sure.


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## begreen (Jun 17, 2018)

For that distance I'd go 8/3 if power equipment will be a frequent load. If just lighting and an occasional hand tool then 10/3 might suffice. If this is at the shed soften the radius with a wide sweep elbow. Or if this is in ground, eliminate it completely with a gentle curve over a greater length of the conduit.


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## zrock (Jun 17, 2018)

Pull the wire through as you bury the conduit. Or run a rope through it while burring it and pull it through.. Put a extra pull rope/string in the conduit as well incase in the future you want to add something else.


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## Don2222 (Jun 17, 2018)

Hello
I did the direct burial, I do not like the idea of water collecting in conduit.
See all my pics and detail here.
Hope this helps
https://www.hearth.com/talk/threads...ld-i-use-10-3-uf-b-or-10-2-uf-b-and-is.76717/
BGreen remember? I had to upgrade the main panel from 100 amp to 200 amp to have a 30 amp breaker for the shed to do it correctly. 
https://www.hearth.com/talk/threads...box-in-new-circuit-panel.137937/#post-1852573
Good luck


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## xman23 (Jun 17, 2018)

All excellent suggestions. As Bgreen said, whats the service for. If your running motors that have starting current, oversize the wire based on the distance. See the online calculators for this.  Whatever you use avoid any 90's. I like the Idea of sliding the pipe over the wire.


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## RustyShackleford (Jun 17, 2018)

Ashful said:


> Pulling UF-B thru conduit can be a bear, if favor THHN.  In overhead conduit, I use what’s called a “pulling elbow” or an outlet body (eg. Type LB), when I need to install a 90 elbow, but you’d have to check to see if they’re rated for burial.


Since even the inside of a conduit is a "wet" location, I don't see why it'd be a problem.   But since underground, it doesn't really help unless I pull the wire as I bury, in which case I don't really need it.



> I can look in my book tonight for minimum conduit size, but have you de-rated your conductors for distance, if over 100 feet total from breaker to load?


It's definitely under 100ft.    Wire can crry the same amperage regardless of distance, except, of course, for voltage drop.    The resistance of 10awg is exactly a milli-ohm per foot, so my <200ft round-trip would drop <6 volts when pulling the full 30 amps.  I think that's ok.



begreen said:


> For that distance I'd go 8/3 if power equipment will be a frequent load. If just lighting and an occasional hand tool then 10/3 might suffice.


I've been using a heavy-grade extension cord (probably 12awg, certainly not over 10awg), on a house circuit protected by 20 amp breaker, and it's fine.  I can start up compound-miter saw while small pancake compressor is running, and no issue - that's good enough for me.



> If this is at the shed soften the radius with a wide sweep elbow. Or if this is in ground, eliminate it completely with a gentle curve over a greater length of the conduit.


Trench is dug, machine returned.    No long gentle curve is gonna happen, but wide-sweep elbow will fit.



zrock said:


> Pull the wire through as you bury the conduit. Or run a rope through it while burring it and pull it through.. Put a extra pull rope/string in the conduit as well incase in the future you want to add something else.


Good ideas.   One thing i wonder: it means you gluing the next piece of conduit with the wire already pulled past the joint; is it ok to get the PVC cement on the wire ?



Don2222 said:


> Hello
> I did the direct burial, I do not like the idea of water collecting in conduit.


Ship has sailed: trench dug, machine returned.

So back to my original question: assuming I'll pull the wire AS I'm burying the conduit, should I go to the trouble of replacing the UF-B with THHW ?   And, what size conduit should I use ?


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## begreen (Jun 17, 2018)

A hard 90 may be required above ground at the building. If so, use a type LB for pulling access.


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## begreen (Jun 17, 2018)

RustyShackleford said:


> It's definitely under 100ft. Wire can crry the same amperage regardless of distance, except, of course, for voltage drop. The resistance of 10awg is exactly a milli-ohm per foot, so my 200ft round-trip would drop 6 volts when pulling the full 30 amps. I think that's ok.


It depends on the incoming line voltage and what's normally running in the shed. If at a later date a freezer or beer fridge is added, this can matter.


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## RustyShackleford (Jun 17, 2018)

begreen said:


> A hard 90 may be required above ground at the building. If so, use a type LB for pulling access.


Definitely planning to use those.  Am I correct that, if I end up using THHW, I could make the splice between NM-B from the breaker box and the THWW, inside the LB elbow ?   (Because it can't be ok to run the THHW all the way to the breaker, unless I run it in conduit of some kind, a PITA, since a rather tortuous path).

What about those slip joints, that allow movement between the LB elbow on the side of the two buildings, and the buried conduit ?  When are they required ?    They are expensive !   Not much frost-heave here in the sunny south - is that the issue ?


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## Don2222 (Jun 17, 2018)

I have 2 - 20 amp breakers in the small 2 breaker circuit Panel in the shed with all yellow 12 Guage Wiring. I put a compressor on one breaker and saw and vac on the other breaker. No problems. Since I built a new workshop next to the house with 80 amps, 50 for my welder, it is all set.


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## RustyShackleford (Jun 17, 2018)

> One thing i wonder: it [pulling the wire as you bury the conduit] means you gluing the next piece of conduit with the wire already pulled past the joint; is it ok to get the PVC cement on the wire ?


A quick googling suggests, as I suspected, that it is NOT ok to get PVC cement on wire - since it basically does a solvent weld.   So I guess the solution is to run a pull cord in the PVC as I'm burying it, and then use that to pull the wire.

All this is making me think I should definitely use THHW (and return the UF-B).  And wireandcableyourway.com sells 8awg by the foot but 10awg only by 100ft rolls, so since I only need 80ft or so, it won't cost much more to go with 8awg.  So I might do that after all.   Given that: what size conduit ?   Considering conduit is cheap.


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## RustyShackleford (Jun 17, 2018)

Don2222 said:


> I have 2 - 20 amp breakers in the small 2 breaker circuit Panel in the shed with all yellow 12 Guage Wiring. I put a compressor on one breaker and saw and vac on the other breaker. No problems.


But what size breaker protects the feed to the shed ?    Double-pole 20 amp, I presume.


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## begreen (Jun 17, 2018)

I don't believe it is ok to splice in an LB fitting unless there is enough volume. @fbelec would know. Wondering if instead you could use an outdoor outlet box with a gasketed cover. What diameter conduit will you be using, 3/4"?

https://www.homedepot.com/p/BELL-1-...1-2-in-or-3-4-in-Outlets-PSB37550WH/202284521


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## Don2222 (Jun 17, 2018)

RustyShackleford said:


> But what size breaker protects the feed to the shed ?    Double-pole 20 amp, I presume.


The main panel has a 30 amp 220v breaker because the shed panel is rated for 30 AMP 220vac and the wire is 10-3 UF-B
The conduit goes 3 feet below ground and then the direct burial cable is just in the dirt. After 12” of dirt, the red electric cable warning tape was laid in. Remember Dig Safe! 
The small conduit is for the phone & cable TV wires, don’t forget those to have with the kegerator!


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## RustyShackleford (Jun 17, 2018)

Don2222 said:


> The main panel has a 30 amp 220v breaker ...


You didn't use the expansion couplings ?   I can't decide on that.   They say if things will move more than 1/4".   The horizontal buried run is not an issue because the soil is so constant temperature.    The coefficient of thermal expansion of the PVC is 34ppm per degree-F.    So if your riser comes up 50" out of the ground, a 100 degree temperature swing is gonna move it about 1/6".   So should be ok.   Except for ground settling and/or frost heave.   Would be a no-brainer, but those things are expensive.   I'm already pissed about having to buy PVC at all (since I couldn't get to 24" deep).


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## RustyShackleford (Jun 17, 2018)

begreen said:


> I don't believe it is ok to splice in an LB fitting unless there is enough volume.


Those things are huge; even if I go to #8 wire, it's only 3 cu-in per wire, or 21 cu-in (ground counts as 1, I believe).

But, it turns out it's not ok just sufficient for the box to be big enough, its size needs to be marked: https://www.ecmag.com/section/codes-standards/box-fill-calculations-part-xii . (scroll down to 314.16(C)(2))

Weird, since for normal boxes, they aren't required to be marked (I think, at least I rarely see it on metal ones).

I will be using much larger than 3/4" conduit.   But that's one thing I'm trying to get an answer to: how big should I go ?   (I don't care about the conduit fill calculations, those are ludicrous, at least for a run this long).


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## Don2222 (Jun 17, 2018)

RustyShackleford said:


> You didn't use the expansion couplings ?   I can't decide on that.   They say if things will move more than 1/4".   The horizontal buried run is not an issue because the soil is so constant temperature.    The coefficient of thermal expansion of the PVC is 34ppm per degree-F.    So if your riser comes up 50" out of the ground, a 100 degree temperature swing is gonna move it about 1/6".   So should be ok.   Except for ground settling and/or frost heave.   Would be a no-brainer, but those things are expensive.   I'm already pissed about having to buy PVC at all (since I couldn't get to 24" deep).


Hello
All 8 cement blocks under the shed rest on 2 foot deep holes filled with 1/4” stone! The heavy duty steel entry door still opens and closes fine after 5 years because of the stones the shed has not settled not even 1 millimeter!

Don’t forget a heater for the winter! I installed a small wood pellet stove that I can turn on from the main house. No sense going out to a cold shed. 
Also to help on heating in the winter and cooling in the summer I suggest reflectix foil on top of your shed insulation for a good thermal break!
See mine
https://www.hearth.com/talk/threads/shed-roof-thermal-relief-for-winter-summer.84824/#post-1112024


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## RustyShackleford (Jun 17, 2018)

Don2222 said:


> Hello
> All 8 cement blocks under the shed rest on 2 foot deep holes filled with 1/4” stone! The heavy duty steel entry door still opens and closes fine after 5 years because of the stones the shed has not settled not even 1 millimeter!


Mine is a shipping container.  One thing I could do is to simply not cement the joint were the riser goes into the LB box: the inside of conduit is a "wet location", so doesn't seem like it really matters if a smidgen of water gets it there.  The main point of the conduit, I believe, is to simply project the wire within; that would still be the case.



> Don’t forget a heater for the winter! I installed a small wood pellet stove that I can turn on from the main house. No sense going out to a cold shed.


I'm in NC, not NH


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## Don2222 (Jun 17, 2018)

Yes the conduit is just to protect the wire from something bumping into it and hungry rodents like squirrels that chew the wires!
NC does not get as cold and snowy as up here!


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## begreen (Jun 17, 2018)

FWIW there are no expansion joints on our ~50' run from the house to the garage.


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## RustyShackleford (Jun 17, 2018)

begreen said:


> FWIW there are no expansion joints on our ~50' run from the house to the garage.


I think it's the vertical risers where they might be needed.  Even Carlon says you don't need 'em for buried horizontal runs, because the soil temperature is so nearly constant.


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## begreen (Jun 17, 2018)

Yes, understood, I should have been more specific. Our vertical risers before the garage LB and panel end don't have them. Our climate is mild like yours.


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## fbelec (Jun 18, 2018)

i've never spliced in a LB because there is not much room and you don't bend the wires to sharp that there could be a weak spot. a box is a good thing it's where the romex can splice into the uf cable without a code violation. some codes are dumb and we have to follow them anyway but putting a expansion fitting where a pvc comes out of the ground is a good thing. more than half the time i come across a pipe without one it usually breaks the knock outs out of a meter socket or breaks the box


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## fbelec (Jun 18, 2018)

a number 10 wire spliced into a box or anything grounds count as one wire but rest is 2.5 cubic times 6. white red and black are 3 and the other white red and black are 3 different wires. so that splice is 17.5 cubic fill


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## tadmaz (Jun 18, 2018)

I ran 100amp to my detached garage a few years ago.  #1 aluminum NM in the basement stapled to the floor joists, splice using Panduit splicers inside of a large junction box to #3 copper THHN.  2" LB's and PVC.  PVC from the junction box to LB fitting, PVC underground 18" to other LB, PVC to electrical box in garage.  Unbond ground and neutral in garage electrical box.  Pound in 8' grounding rod, #6 copper to garage electrical box.  Used a pull string and wire pulling lubricant, no problems with 2" PVC.


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## RustyShackleford (Jun 18, 2018)

fbelec said:


> a number 10 wire spliced into a box or anything grounds count as one wire but rest is 2.5 cubic times 6. white red and black are 3 and the other white red and black are 3 different wires. so that splice is 17.5 cubic fill


Right, or 21 cu-in if I decide to go up to 8awg.   I looked at the 1-1/4 LB boxes I have and they ARE marked with their volume (as code requires if they are used for junctions) and well in excess of 21 cu-in.   Plus I'm seriously thinking about increasing to 1-1/2".

I still have remaining questions:

1. What size conduit should I use ?   Seems like going up to 2" is silly, as it sounds like @tadmaz found it to be plenty even for 3awg wire.  Tempted to increase from 1-1/4" to 1-1/2" since I calculate it'll cost me a mere $10 extra, and I do have that underground right-angle fitting.  

2. If I switch to THHW (and return the UF-B), can I increase to 35 amps or to 40 amps ?   I'm very confused by the relevant NEC table:

http://www.usawire-cable.com/pdfs/nec ampacities.pdf

... and as regarding the wire I'd probably use (if I switch):

https://www.wireandcableyourway.com/THHN-THWN/


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## Ashful (Jun 18, 2018)

My limited experience, I’ve never regretted going too big, but I’ve often regretted going too small.  The regret comes two years from now, when you decide you want to add a 3-way switching circuit (or two) to control the exterior shop/shed lights from the house.

At $10 incremental cost, I’d always favor going at least one or two sizes over minimum required.


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## RustyShackleford (Jun 18, 2018)

Ashful said:


> At $10 incremental cost, I’d always favor going at least one or two sizes over minimum required.


Makes sense.   Plus, since I can get 8awg by the foot, and I only need 80 ft (as opposed to 100ft rolls of 10awg), it's almost as cheap to run 8awg, so I think I'll do that.

Running THHW/THWN, if I go 8awg, the EGC wire only needs to be 10awg, right, and it can be bare uninsulated wire ?


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## RustyShackleford (Jun 18, 2018)

Or use XHHW, which sounds like it's just fine for underground in conduit, and is sold by the foot in 10awg (at wireandcableyourway-dot-com)


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## fbelec (Jun 18, 2018)

if you are going with 8 then it should handle the 40 amp. if your going with LB instead of boxes pull 3 14ga wires in with it for the possible 3 way cuz you won't be able to pull thru LBs after. i'll bet the small pvc box is cheaper than the LB then the only 90 degree bends should be pipe sweeps so future pulls are easy.


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## RustyShackleford (Jun 19, 2018)

fbelec said:


> if your going with LB instead of boxes pull 3 14ga wires in with it for the possible 3 way cuz you won't be able to pull thru LBs after. i'll bet the small pvc box is cheaper than the LB then the only 90 degree bends should be pipe sweeps so future pulls are easy.


I'm not following.  Why won't I be able to pull thru my LBs after ?     Isn't that what they're designed for ?   And whatever I do, I'll have a 90 where the underground line kinks, and a 90 where each end comes up out of the ground.


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## begreen (Jun 19, 2018)

Once wires are in a conduit it is hard to pull additional wires. Use a metal snake to pull the wires, not rope. 

Instead of a 3-way, I decided to put outside motion detecting lights at the garage entrances.


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## RustyShackleford (Jun 19, 2018)

begreen said:


> Once wires are in a conduit it is hard to pull additional wires.


My conduit is grossly oversized, using 1-1/2" for four 10awg XHHW conductor.   So I hope for the best.  Still better off than I would have been if I'd been able to get the damn ditch 24" deep and used the UF-B.   I guess the fallback (if I want to add wires) is to disconnect and pull the existing wires and start over.



> Use a metal snake to pull the wires, not rope.


Why ?   You mean if I need to add wires later ?   For the initial, I was going to string old climbing rope thru the PVC as I install it (not the wire, so as not to get PVC dope on the wire insulation), and use that rope to pull the 4 strands of XHHW and a light nylon cord for future work.


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## RustyShackleford (Jun 19, 2018)

RustyShackleford said:


> Those things are huge; even if I go to #8 wire, it's only 3 cu-in per wire, or 21 cu-in (ground counts as 1, I believe).
> 
> But, it turns out it's not ok just sufficient for the box to be big enough, its size needs to be marked: https://www.ecmag.com/section/codes-standards/box-fill-calculations-part-xii . (scroll down to 314.16(C)(2))


Interesting followup, there's some character over at stackexchange who has made this erroneous statement (that you can't splice in an LB), and when I corrected him, well, let's just say he wasn't happy (see last few comments after the one "answer"):

https://diy.stackexchange.com/questions/123384/pulling-wire-through-emt-and-pvc-conduit

His answer was actually quite good, except for that one mistake.

Stackexchange is a weird place: Half the time I ask a question there, I get more bitching and moaning about how I asked the question, or was it in the right forum, that actual helpful responses.


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## begreen (Jun 19, 2018)

RustyShackleford said:


> My conduit is grossly oversized, using 1-1/2" for four 10awg XHHW conductor.   So I hope for the best.  Still better off than I would have been if I'd been able to get the damn ditch 24" deep and used the UF-B.   I guess the fallback (if I want to add wires) is to disconnect and pull the existing wires and start over.
> 
> Why ?   You mean if I need to add wires later ?   For the initial, I was going to string old climbing rope thru the PVC as I install it (not the wire, so as not to get PVC dope on the wire insulation), and use that rope to pull the 4 strands of XHHW and a light nylon cord for future work.



Multiple reasons. A metal snake (fish tape)  will eliminate the need to thread as the pipe is laid down. Rope, especially poly or nylon may get glued? A metal snake stays much more rigid in a pipe for smooth pulls. They are cheap at Harbor Freight. https://www.harborfreight.com/100-ft-fish-tape-3891.html

1.5" conduit is really big for 4 #10s so pulling additional wires may not be an issue with a pull rope already in place. But if you are planning on future updates, then why not get them done now? The issue with pulling additional wires is that they may wrap around (over and under) the existing wires and cinch up. It can be done, but sometimes is a real hassle.


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## tadmaz (Jun 19, 2018)

Come to think of it, I think I used metal fish tape (like above) and the chinese finger trap type device to connect the wire to the fish tape.


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## Ashful (Jun 19, 2018)

When I add additional wiring to the conduit, I always disconnect the original wire bundle, use it to pull the snake back thru, tie in the new wire, and re-pull the entire bundle.  My pulls are almost always under 200 feet, so it’s not a big deal, and it keeps everything neat and tidy, soothing my overly anal-rentitive tendencies.  Also, even with oversized conduit, pulling a snake and new wire past bends can be a bear, and I worry about the possibility of the snake rubbing one of the existing wires in the bend.


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## RustyShackleford (Jun 19, 2018)

Ashful said:


> When I add additional wiring to the conduit, I always disconnect the original wire bundle, use it to pull the snake back thru, tie in the new wire, and re-pull the entire bundle.


I thought of that, but it seems like it puts a lot of wear and tear on the insulation of the older wires.


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## Ashful (Jun 19, 2018)

RustyShackleford said:


> I thought of that, but it seems like it puts a lot of wear and tear on the insulation of the older wires.



Maybe.  But I suspect not nearly as much as running 100+ feet of metal fish tape past a fixed point of existing wire insulation in a swept conduit elbow.


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## xman23 (Jun 19, 2018)

If I remember my industrial wiring. No more than 2, 90's. And pulling around 2 90's is not easy. No splices where you can't access it. I think you are doing LB underground, so no splicing there.  Avoid splices, there only potential bad connections. 

I would consider pulling some of these. A few pairs of 14 gauge, cable line, cat 5,  a multi cable with a number of twisted shielded pairs.


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## RustyShackleford (Jun 19, 2018)

xman23 said:


> If I remember my industrial wiring. No more than 2, 90's. And pulling around 2 90's is not easy. No splices where you can't access it. I think you are doing LB underground, so no splicing there.  Avoid splices, there only potential bad connections.


Hmm, there's already two 90s, where the risers to the LB boxes on the two buildings (house and shed) come out of the ground.  So no 90s allowed in the horizontal run ?    Glad I'm using way-too-big conduit then.

I am most definitely NOT using an LB underground.   There IS a 90-degree bend underground though.  And I'm certainly not intending to splice underground.    I will splice NM from the main breaker box to the XHHW from the shed, in the LB on the side of the house (treating it as a junction box and noting that it's easily got enough volume, which volume is clearly marked).


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## fbelec (Jun 20, 2018)

those two 90's are ok  leave them and just pull your wires. i think your starting to over engineer the simple job of a circuit thru a pipe. your doing fine with the size pipe you have. i pulled a 430 foot service from the house out to the transformer 4 90 degree bend but only used 3 90's. one bend was sweeped over gradually. 2 inch pipe 3 250 mcm wires. legal with the code book. had to use a truck to pull the copper wires in the pipe and 3 people feeding it. 2 gallons of wire ease. in that pull the owners truck had 17000 miles and tranny got so hot it melted a plastic tranny line connector turned the fluid black and call a hook for that dodge truck. got a backhoe to finish he managed to get 20 feet pulled. to much for the backhoe. the hook arrived we talked him into using his winch. he had his truck on two wheels sideways and broke the 10000 pound tinsle strength rope. thought someone was going to lose a head with steel line coming out at us. backhoe dug so we could hook the rope again and then i hooked up my e350 and pulled the rest of 80 feet til the rope broke again. finished the next day by taking off 1 of the 90's and it just about slid itself in the last 20 feet. long story but that's how 1 90 degree fitting can make it miserable


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## begreen (Jun 20, 2018)

fbelec said:


> those two 90's are ok  leave them and just pull your wires. i think your starting to over engineer the simple job of a circuit thru a pipe. your doing fine with the size pipe you have. i pulled a 430 foot service from the house out to the transformer 4 90 degree bend but only used 3 90's. one bend was sweeped over gradually. 2 inch pipe 3 250 mcm wires. legal with the code book. had to use a truck to pull the copper wires in the pipe and 3 people feeding it. 2 gallons of wire ease. in that pull the owners truck had 17000 miles and tranny got so hot it melted a plastic tranny line connector turned the fluid black and call a hook for that dodge truck. got a backhoe to finish he managed to get 20 feet pulled. to much for the backhoe. the hook arrived we talked him into using his winch. he had his truck on two wheels sideways and broke the 10000 pound tinsle strength rope. thought someone was going to lose a head with steel line coming out at us. backhoe dug so we could hook the rope again and then i hooked up my e350 and pulled the rest of 80 feet til the rope broke again. finished the next day by taking off 1 of the 90's and it just about slid itself in the last 20 feet. long story but that's how 1 90 degree fitting can make it miserable


 Wow. That is one service install you'll never forget.


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## CaptSpiff (Jun 20, 2018)

fbelec said:


> those two 90's are ok  leave them and just pull your wires. i think your starting to over engineer the simple job of a circuit thru a pipe. your doing fine with the size pipe you have. i pulled a 430 foot service from the house out to the transformer 4 90 degree bend but only used 3 90's. one bend was sweeped over gradually. 2 inch pipe 3 250 mcm wires. legal with the code book. had to use a truck to pull the copper wires in the pipe and 3 people feeding it. 2 gallons of wire ease. in that pull the owners truck had 17000 miles and tranny got so hot it melted a plastic tranny line connector turned the fluid black and call a hook for that dodge truck. got a backhoe to finish he managed to get 20 feet pulled. to much for the backhoe. the hook arrived we talked him into using his winch. he had his truck on two wheels sideways and broke the 10000 pound tinsle strength rope. thought someone was going to lose a head with steel line coming out at us. backhoe dug so we could hook the rope again and then i hooked up my e350 and pulled the rest of 80 feet til the rope broke again. finished the next day by taking off 1 of the 90's and it just about slid itself in the last 20 feet. long story but that's how 1 90 degree fitting can make it miserable



Oversize your conduit, keep your workers happy. 
Oh,.. and don't be cheap with the cable lube, that's what new guys are for. 

Pulling problems are one of the leading causes of unscheduled OT.
And Yup, your equipment breakdowns were the result of pulling problems.


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## Andyman (Jun 20, 2018)

One of the few things i remember from electrical school is that 4-90's is the max in a single run. (360 degrees total for all bends)


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## RustyShackleford (Jun 20, 2018)

Andyman said:


> One of the few things i remember from electrical school is that 4-90's is the max in a single run. (360 degrees total for all bends)


Assuming you don't count the LB bodies at each end, and do count where the risers to the LB bodies go into the ground, I'll have three 90s and a 45.


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## xman23 (Jun 20, 2018)

fbelec said:


> those two 90's are ok  leave them and just pull your wires. i think your starting to over engineer the simple job of a circuit thru a pipe. your doing fine with the size pipe you have. i pulled a 430 foot service from the house out to the transformer 4 90 degree bend but only used 3 90's. one bend was sweeped over gradually. 2 inch pipe 3 250 mcm wires. legal with the code book. had to use a truck to pull the copper wires in the pipe and 3 people feeding it. 2 gallons of wire ease. in that pull the owners truck had 17000 miles and tranny got so hot it melted a plastic tranny line connector turned the fluid black and call a hook for that dodge truck. got a backhoe to finish he managed to get 20 feet pulled. to much for the backhoe. the hook arrived we talked him into using his winch. he had his truck on two wheels sideways and broke the 10000 pound tinsle strength rope. thought someone was going to lose a head with steel line coming out at us. backhoe dug so we could hook the rope again and then i hooked up my e350 and pulled the rest of 80 feet til the rope broke again. finished the next day by taking off 1 of the 90's and it just about slid itself in the last 20 feet. long story but that's
> how 1 90 degree fitting can make it miserable



Frank,
You start by saying leave those 90. Then your burning up a truck pulling thru your 90. So funny.


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## fbelec (Jun 20, 2018)

begreen said:


> Wow. That is one service install you'll never forget.


never


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## fbelec (Jun 20, 2018)

CaptSpiff said:


> Oversize your conduit, keep your workers happy.
> Oh,.. and don't be cheap with the cable lube, that's what new guys are for.
> 
> Pulling problems are one of the leading causes of unscheduled OT.
> And Yup, your equipment breakdowns were the result of pulling problems.


i am usually a oversize guy but at that time the cost was big for a reduced rate for buying 500 feet and i did what at the time boston edison use to require and that was use copper underground not aluminum. at that time it was transitioning to aluminum the customer was complaining why the cost of the service was high and the other houses on the street were aluminum i couldn't add on any more


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## fbelec (Jun 21, 2018)

Andyman said:


> One of the few things i remember from electrical school is that 4-90's is the max in a single run. (360 degrees total for all bends)


that's right and that's what i had


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## fbelec (Jun 21, 2018)

xman23 said:


> Frank,
> You start by saying leave those 90. Then your burning up a truck pulling thru your 90. So funny.


when i said that it sounded like rustyshakleford was going to bury the Lbs. if you can get away with the 45 degree instead of a 90 do it. and by the way out of 6 houses on the street he was the only copper service and no issue's 3 other houses aluminum services blew up


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## RustyShackleford (Jun 21, 2018)

fbelec said:


> ti think your starting to over engineer the simple job of a circuit thru a pipe.


Hey, as a work buddy says (fellow engineer), "anything worth doing is worth over-doing".


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## Ashful (Jun 21, 2018)

fbelec said:


> he was the only copper service and no issue's 3 other houses aluminum services blew up


That’s a surprise.  Every home I’ve ever owned, including my current house, has aluminum mains.  I suspect it’s all they use around here.  Unlike the aluminum wiring they tried using in houses in the late 1960’s (much of which failed or caused fires), I’ve never heard of anyone having any problem with aluminum mains, assuming they’re buttered and tightened properly into approved lugs.


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## Andyman (Jun 21, 2018)

RustyShackleford said:


> Assuming you don't count the LB bodies at each end, and do count where the risers to the LB bodies go into the ground, I'll have three 90s and a 45.



As long as you can access the openings in the LB's, they would count as the beginning and end of the run, yours looks good.


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## RustyShackleford (Jun 21, 2018)

Andyman said:


> As long as you can access the openings in the LB's, they would count as the beginning and end of the run, yours looks good.


Thanks guys.   I think we've beaten this problem into submission.  For the record, I decided to return the UF-B and go with 8awg XHHW, in 1-1/2" conduit in case I want to add stuff later.

One last question: This joker at stackexchange insists you can't splice in the LB body.   Which I want to connect NM from my main load center to the XHHW, at the LB body at the beginning of the run on the side of my crawlspace.  When I point out he's wrong, he grudgingly admits, but still insists you'd be a moron to do this (instead of adding a separate junction box, which you need somehow to protect the XHHW going from theLB to this junction box, as I don't think you're allowed to have unprotected XHHW or THHN even in a crawlspace).   I think his arguments are silly.   What do you guys think:

https://diy.stackexchange.com/questions/123384/pulling-wire-through-emt-and-pvc-conduit

See comments after the "answer".


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## Andyman (Jun 21, 2018)

RustyShackleford said:


> Thanks guys.   I think we've beaten this problem into submission.  For the record, I decided to return the UF-B and go with 8awg XHHW, in 1-1/2" conduit in case I want to add stuff later.
> 
> One last question: This joker at stackexchange insists you can't splice in the LB body.   Which I want to connect NM from my main load center to the XHHW, at the LB body at the beginning of the run on the side of my crawlspace.  When I point out he's wrong, he grudgingly admits, but still insists you'd be a moron to do this (instead of adding a separate junction box, which you need somehow to protect the XHHW going from theLB to this junction box, as I don't think you're allowed to have unprotected XHHW or THHN even in a crawlspace).   I think his arguments are silly.   What do you guys think:
> 
> ...



NEC Article 370-5 states that you are not to splice in a "short radius conduit body" such as a "capped elbow" or "service entrance elbow"
NEC Article 370-16(c) States in paragraph 2:
"Conduit bodies shall not contain splices, taps, or devices unless they are durably and legibly marked by the manufacturer with the cubic inch capacity. The maximum number of conductors shall be computed using the same procedure for similar conductors in other than standard boxes"

Edit - my code book is a bit old, (as am I), so double checking would be prudent.


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## RustyShackleford (Jun 21, 2018)

Andyman said:


> "Conduit bodies shall not contain splices, taps, or devices unless they are durably and legibly marked by the manufacturer with the cubic inch capacity. The maximum number of conductors shall be computed using the same procedure for similar conductors in other than standard boxes"


My LBs are durably and legibly marked at 32 cu-in.    So they can have my 2*3+1 of 8awg wire count, with 11 cu-in left over.

I'm curious of people think the objections given to doing this by that Harper guy have any merit, or if he's just trying to argue away the fact that I found a mistake in his "answer".


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## Andyman (Jun 21, 2018)

RustyShackleford said:


> My LBs are durably and legibly marked at 32 cu-in.    So they can have my 2*3+1 of 8awg wire count, with 11 cu-in left over.
> 
> I'm curious of people think the objections given to doing this by that Harper guy have any merit, or if he's just trying to argue away the fact that I found a mistake in his "answer".




I was an industrial electrician for 15 years, and I've seen a LOT of splices in conduit bodies, some on the machines i was working on, and some in the routing to the equipment. I myself don't see any problem with it.


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## Ashful (Jun 21, 2018)

RustyShackleford said:


> I'm curious of people think the objections given to doing this by that Harper guy have any merit, or if he's just trying to argue away the fact that I found a mistake in his "answer".


He’s wrong to have said it’s not permitted by code, but he is right that there are better ways to do it.  I also prefer mounting a larger box indoors for the splice, rather than doing in the LB.  I actually prefer to put a service loop in the LB, in case I ever need an extra few inches of wire after doing some repair or expansion on that line.


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## fbelec (Jun 22, 2018)

RustyShackleford said:


> My LBs are durably and legibly marked at 32 cu-in.    So they can have my 2*3+1 of 8awg wire count, with 11 cu-in left over.
> 
> I'm curious of people think the objections given to doing this by that Harper guy have any merit, or if he's just trying to argue away the fact that I found a mistake in his "answer".



for my own curiosity what brand Lb are you using? can you take a pic of it? I've never seen this.


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## fbelec (Jun 22, 2018)

Ashful said:


> He’s wrong to have said it’s not permitted by code, but he is right that there are better ways to do it.  I also prefer mounting a larger box indoors for the splice, rather than doing in the LB.  I actually prefer to put a service loop in the LB, in case I ever need an extra few inches of wire after doing some repair or expansion on that line.



how could he be wrong if it is in the code book


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## fbelec (Jun 22, 2018)

you are also telling me that if you are running a 100 amp sub panel that you would loop #3 copper in that Lb????????????


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## fbelec (Jun 22, 2018)

Ashful said:


> That’s a surprise.  Every home I’ve ever owned, including my current house, has aluminum mains.  I suspect it’s all they use around here.  Unlike the aluminum wiring they tried using in houses in the late 1960’s (much of which failed or caused fires), I’ve never heard of anyone having any problem with aluminum mains, assuming they’re buttered and tightened properly into approved lugs.



i use aluminum on all my services, now. also but this service like the others is underground. this was twenty years ago and up until then the utility would not hook up underground aluminum they just started doing it at that time i just didn't believe it would work well at that time and the home owner was glad that it was copper


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## RustyShackleford (Jun 22, 2018)

fbelec said:


> for my own curiosity what brand Lb are you using? can you take a pic of it? I've never seen this.


From HomeDepot, I'll check later.  What have'n't you seen, the cu-in marking ?


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## RustyShackleford (Jun 22, 2018)

Ashful said:


> He’s wrong to have said it’s not permitted by code, but he is right that there are better ways to do it.  I also prefer mounting a larger box indoors for the splice, rather than doing in the LB.


So how do you get from the LB to the other box ?   You can't just have XHHW or THHN running loose from the LB to the box, even in a crawlspace, can you ?

Do you run a little more conduit ?   If the LB is 1-1/2", there aren't many reasonably-sized boxes with openings that large, so do you cascade a bunch of reducers ?    I have no idea, but sounds like something people do.


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## CaptSpiff (Jun 22, 2018)

Ashful said:


> That’s a surprise.  Every home I’ve ever owned, including my current house, has aluminum mains.  I suspect it’s all they use around here.  Unlike the aluminum wiring they tried using in houses in the late 1960’s (much of which failed or caused fires), I’ve never heard of anyone having any problem with aluminum mains, *assuming they’re buttered* and tightened properly into approved lugs.



Yup, Penetrox is your friend. Better living thru chemicals.

And I also haven't seen a copper service drop to the weather head in 40 years. Meter to the main is a mix. Even the grounds are copper-weld to save money.


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## CaptSpiff (Jun 22, 2018)

fbelec said:


> i use aluminum on all my services, now. also but this service like the others is underground. this was twenty years ago and up until then the utility would not hook up underground aluminum they just started doing it at that time i just didn't believe it would work well at that time and the home owner was glad that it was copper



The 1980's was the transition time when Utilities (some kicking and dragging) updated their construction standards "books", green-lighting aluminum everywhere. The memories of Al-Cu home wiring damage was still too fresh for many back then.

The other thing I recall back then is people pulling Al thru conduit "sized from old copper-conduit tables", that's why I developed my up-size conduit attitude.


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## fbelec (Jun 23, 2018)

thru the code up sizing is mandatory amps wise. i have a few customer now that still have aluminum wire in their homes. 15 amp aluminum is 12ga and 20 amp is 10ga  and as long as it's look on that way there is no problem. up sizing pipe is a good idea but i don't like the idea of pulling hard on a aluminum wire cuz it has no sense of humor. one to many yanks and a weak spot is developed. that is why i used copper for this guy's service. and probably why so many failed on that street. loooong driveways


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## Ashful (Jun 23, 2018)

fbelec said:


> you are also telling me that if you are running a 100 amp sub panel that you would loop #3 copper in that Lb????????????



No, I’ve always run 60 amp subs to out buildings.


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## begreen (Jun 23, 2018)

Ashful said:


> That’s a surprise.  Every home I’ve ever owned, including my current house, has aluminum mains.  I suspect it’s all they use around here.  Unlike the aluminum wiring they tried using in houses in the late 1960’s (much of which failed or caused fires), I’ve never heard of anyone having any problem with aluminum mains, assuming they’re buttered and tightened properly into approved lugs.


My sister just had a buried aluminum main fail. 1982 install date. Power company said they are seeing many of these happen locally.


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## venator260 (Jun 23, 2018)

begreen said:


> My sister just had a buried aluminum main fail. 1982 install date. Power company said they are seeing many of these happen locally.




I'd be curious to know why. I have buried aluminum in conduit (could be galvanized drain pipe; looks the same) from the poll to the meter installed in 1968 when the service was updated from 100 to 200 amp. 3 years ago when I updated the panel, the guys from the power company tested the voltage and were happy with the results.


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## fbelec (Jun 24, 2018)

at one point the power company would spec out that 3 inch pipe for what ever size service
so the telephone company with cable was saying the same. i had a problem not with the service but with the requirement of a 3 inch pipe for a RG6 quad shield in a 3 inch pipe. oversize is one thing stupidity is another. 3 inch pvc pipe is not cheap.


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## CaptSpiff (Jun 24, 2018)

fbelec said:


> at one point the power company would spec out that 3 inch pipe for what ever size service
> so the telephone company with cable was saying the same. i had a problem not with the service but with the requirement of a 3 inch pipe for a RG6 quad shield in a 3 inch pipe. oversize is one thing stupidity is another. 3 inch pvc pipe is not cheap.


No, not cheap... but it's easy to pull thru.


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