underground service wiring conundrum
- Thread starter RustyShackleford
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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
Hey, as a work buddy says (fellow engineer), "anything worth doing is worth over-doing".
Ashful
Minister of Fire
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.
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".
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.
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.
Ashful
Minister of Fire
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.
for my own curiosity what brand Lb are you using? can you take a pic of it? I've never seen this.
you are also telling me that if you are running a 100 amp sub panel that you would loop #3 copper in that Lb????????????
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
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.
CaptSpiff
Minister of Fire
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
Minister of Fire
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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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
Ashful
Minister of Fire
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.
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.
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.
CaptSpiff
Minister of Fire
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