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al vs copper

bjochman

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Jun 7, 2009
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55
Location
Seymour, WI
Any reason not to use AL wire for service to my garage? It will be in pvc conduit underground. Opinions appreciated.
Thanks.
 
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sberry

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Jun 18, 2005
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Brethren, Michigan
The power fed to your place is coming down aluminum conductors. A lot has to do with distance and cost, long runs get aluminum most of the time.
 

Falcon67

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Jun 11, 2009
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18,371
Location
Merkel, TX
I have some aluminum triplex left over from another service entrance that I was going to run overhead to the shop to replace some 6-3 cable I got on the cheap. I have copper on both ends. From my brief research, unless you are terminating at a CU/AL rated device (breaker, panel lugs, etc) your best bet to tie AL to CU is to use a plated brass splice that keeps the condutors separate and to use some dielectric grease on the AL connection. Or a weather tight crimp splice like that used by the power co. I'm still looking for the right splices.
 
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bward76

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Jan 19, 2009
Messages
25
No problems with AL.. A lot of fellow contractors I know have started using it quite a bit more due to copper costs. Just be sure to use AL or AL/CU rated lugs or splices. Nolox is a must for any termination with AL. Plan on checking the torque a few years down the road. I'm not sure about needing Brass, that maybe an area specific thing. We use any kind of Burndy, or T&B as long as it's rated. Personally I wouldn't worry about trying to turn it into copper as it would be adding unnecessary splices. I would use it and take it point to point. Just my 2 cents.
 
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bjochman

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Jun 7, 2009
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55
Location
Seymour, WI
it's a 130 foot run. #2 AL is $86 (3 runs), #2 CU is $336. I would rather save the money, but i don't want to burn my garage down...Sounds like AL is ok as long as i check connections every couple of years?
 

Gary S

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Dec 27, 2008
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Bismarck, ND
Your price difference between aluminum and copper would be less than you stated.
You don't compare #2 aluminum to #2 copper.
#2 copper is roughly equal to 1/0 aluminum for amperage
#2 aluminum is roughly equal to #4 copper for amperage
 
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porschedude996TT

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Oct 28, 2007
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Santa Maria, California
The Power company in my part of the country has used AL wire underground for years. It is direct bury type. I've only heard of one problem, it just happens it was under my driveway going to the neighbors house. One of the junctions failed. Probably would have happened if it were Copper also...
 

Aceman

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Jan 28, 2007
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Location
Eastern Oregon
Nolox is a must for any termination with AL. Plan on checking the torque a few years down the road.

The aluminum alloy used today doesn't require nolox, it's always recommended but not required. Wire manufacturers also don't recommend retorqueing connections. If you must, the proper way is to snip the end off, restrip, and then retorque.

So are you saying that they direct buried a splice?

It's done all the time with direct burial wire and it's legal. It isn't an issue. We use the T&B shrinktube with the scotchkote type sealant in it like Charles mentioned, makes a great underground waterproof splice.
 

bward76

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Jan 19, 2009
Messages
25
I'm sorry I didn't finish my sentence. I'm amazed they would direct buy a splice under your driveway especially from one house to another. I KNOW very legal. Just seems like poor planning on the utility's part.

Anyway, Your correct, Aceman...Save the 6 bucks, don't use the nolox and put enough of a loop of 1/0 into the panel to re-terminate every couple years. Maybe you could build a spreadsheet on how many years an 18" loop will buy you and put it behind the panel schedule.
 

porschedude996TT

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Oct 28, 2007
Messages
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Location
Santa Maria, California
When I was doing some research on a power upgrade at the house, I found that the power companies are not governed by any chapter in the NEC. They are governed by the various PUC's around the country. Their only requirement is to provide safe power to consumers. I was told this by a PG&E Project Engineer who was telling me that I needed to use 4" conduit between the power box and my house and I tried to argue that the NEC only requires...he stopped me short and said that we don't follow the NEC.
 
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