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-   -   driving wire through buried conduit (http://www.diychatroom.com/f18/driving-wire-through-buried-conduit-48228/)

amakarevic 07-06-2009 01:48 PM

driving wire through buried conduit
 
my detached shed will have a 50A subpanel and connected to the main panel by gauge 6 wire. i have already run the indoor portion, which is cable 6/3 and waiting to do some more digging outside so that i bury the conduit.

originally, i was planning to use 6/3 UF wire for the outside without conduit but, since i will also be burying water supply and sewer, decided to go with a conduit and regular wire. however, what i am trying to decide is whether to go with 6/3 NM cable or individual wires. someone recommended individual cause of the heat issue with the outer coat of insulation within a conduit as well as the same coat giving resistance while driving through. what do you guys recommend ?

as a bonus question, as someone who has never really driven wire through conduit, what should be my limits in terms of distance or number of 90 deg elbows that i should realistically expect myself to be able to drive ? e.g. looking from afar, i wouldn't dare take a stab at more than 2-3 max elbows over a 10-15 ft distance at a time cause of jamming. wondering what the pros think ?

Scuba_Dave 07-06-2009 02:07 PM

NM cable can't go in a conduit - not wet rated
UF is rated for burial, conduit must be big enough to hold the wire
Wire must be THWN rated - wet location

Max elbows without a pull box is 360 degrees
I had (4) 90 degree elbows at a distance of 70'+ w/ (3) #6's & a #8 green ground
I used yellow lube & a snake - easy going
I also oversized my conduit to 1.5" size
#6 is rated for 55a & you can feed with a 60a breaker
I used a small 100a panel w/main breaker in my pool cabana

10-15' should be easy even with 3 elbows
Difficulty will depend on conduit (bigger is better), number of elbows & distance
2 people makes it much easier - I was solo
1 person feeds the wire as the other person pulls on the snake

Some people use all sorts of stuff for lube
I bought the electric lube from HD - $7 I think
Some liquid dish soaps have animal fat in them & smell after a while

amakarevic 07-06-2009 02:11 PM

why does it have to be wet rated if it goes in a conduit ???

i plan to use 1" conduit, will that be sufficient for the type of wire that i need. the guy at HD told me that, if i used 6/3 UF cable (flat and real wide), i don't need conduit.

so, which wire/cable combination should i use ???

jbberns 07-06-2009 02:21 PM

Individual wires are easier to pull. How far do you have to go? Use a fish tape to pull in a 1/4" rope if its really hard. It's going to be in conduit so it's a dry location. (Water usually seaps in though)

amakarevic 07-06-2009 02:25 PM

Quote:

Originally Posted by jbberns (Post 298003)
It's going to be in conduit so it's a dry location.

so, are you saying it is OK to use NM wire ?

Scuba_Dave 07-06-2009 02:26 PM

Conduit buried underground by definition is considered a wet location

You can use UF & direct bury the wire at 24", protected where it goes in & comesout of the trench
Conduit you can bury at 18"
Bring a piece of 1" conduit to the wire & take a look at the cross section of the wire compared to the 1" conduit
I prefer conduit to better protect the wire
And if anything happens you can pull new wire instead of digging again

Scuba_Dave 07-06-2009 02:27 PM

Quote:

Originally Posted by jbberns (Post 298003)
Individual wires are easier to pull. How far do you have to go? Use a fish tape to pull in a 1/4" rope if its really hard. It's going to be in conduit so it's a dry location. (Water usually seaps in though)

Quote:

Originally Posted by amakarevic (Post 298008)
so, are you saying it is OK to use NM wire ?

Absolutely NOT !!

amakarevic 07-06-2009 02:29 PM

OK, which wire then ?

Scuba_Dave 07-06-2009 02:32 PM

Direct burial = UF
Conduit (if big enough) - you could use UF
But better to go with THWN rated individual wires

jbberns 07-06-2009 02:33 PM

Quote:

Originally Posted by Scuba_Dave (Post 298009)
Conduit buried underground by definition is considered a wet location

In the NEC or by you? Just curious

amakarevic 07-06-2009 02:35 PM

Quote:

Originally Posted by Scuba_Dave (Post 298013)
But better to go with THWN rated individual wires

will a 1" conduit support this ?

Scuba_Dave 07-06-2009 02:36 PM

Quote:

Originally Posted by jbberns (Post 298014)
In the NEC or by you? Just curious

You are a journeyman & you are asking me? Really ?
You think conduit underground is a dry location?

300zx 07-06-2009 02:42 PM

Quote:

Originally Posted by amakarevic (Post 298016)
will a 1" conduit support this ?

Yes 1" conduit can have up to 7 -#6

InPhase277 07-06-2009 03:03 PM

Quote:

Originally Posted by jbberns (Post 298014)
In the NEC or by you? Just curious


Article 100: Definitions. Location, Wet: Installations underground or in concrete slabs or masonry in direct contact with the earth; in locations subject to saturation with water or other liquids, such as vehicle washing areas; and in unprotected locations exposed to weather.

There are some of the sharpest electricians here, and some real good DIY'rs as well. This isn't like Mike Holt's forum where you would be ridiculed and beat down over it, but you got to stay on your toes, because you WILL be called out on it. I think it is fair to say that even the most experienced of us have learned something new at one time or another from this lowly DIY forum:thumbsup:.

MacRoadie 07-06-2009 03:04 PM

Quote:

Originally Posted by jbberns (Post 298014)
In the NEC or by you? Just curious

Article 100.

Location:

Wet Location: Installations underground or in concrete slabs or masonry in direct contact with the earth, and locations subject to saturation with water or other liquids, such as vehicle washing areas, and locations exposed to weather and unprotected.

Article 310-8. Wet Locations.

(a) Insulated Conductors. Insulated conductors used in wet locations shall be (1) lead-covered; (2) Types RHW, TW, THW, THHW, THWN, XHHW; or (3) of a type listed for use in wet locations.

Conductors used for direct burial applications shall be of a type listed for such use.


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