shop and home wiring advice?

THEFERMANATOR · #1 07-12-2007, 12:10 AM

I'm doing some electrical work at home trying to get my shop and trailer in order so I can move in. I need to replace the wire going to them and I am at a cross road between ALUMINUM or COPPER. It will be buried inside of SCH40 conduit for the whole run and is for a 100 amp service to both places. One run is about 80 feet and the other is almost 150 feet from the pole. I've already checked the code book and I'll need either number 3 COPPER or number 2 ALUMINUM. My big dilemna is that copper is over twice as much as aluminum, but I keep hearing bad stories about aluminum failing in a year or two.

Any electricians out there have any advice to offer?

rb437 · #2 07-12-2007, 12:23 AM

I'm not an electrician but when I had my home inspected before I bought it I talked to the inspector and he said copper is prefered. Something aout mixing copper and aluminum conductors and different expansion and contraction rates with temperature change which = loose connections which = higher resistance which = fire hazzard. I don't know if I got that exactly right but i'm sure he prefered copper.

Skools Out · #3 07-12-2007, 12:25 AM

being in Fla as you are you should use Copper, i've replaced my feeder at the coast due to salt eats up the aluminum at the lugs and it eats it up in the skin, now all copper at the coast but if you were here and not near any salt i'd say use Aluminum

THEFERMANATOR · #4 07-12-2007, 12:49 AM

I'm 30 miles inland, so salt isn't a concern. Cost is a major concern though. I'm needing almost 800 feet total by the time I get from the pole to the breaker box's. So 95 cents a foot vs 44 cents a foot really adds up. I just don't want to have to redo it in 2 or 3 years.

Skools Out · #5 07-12-2007, 01:21 AM

well that's close enough for salt it is in your air. i'm running my shop on 750 ft of copper 1/0 due to welders and compressors it has a 300 amp service, i'd pay the difference for copper and do it once and do it right.

turbinedoctor · #6 07-12-2007, 03:06 AM

As far as salt goes, I can see the ocean from my front yard and I have aluminum service into my house. I have been in the electrical field for about 20 years now and I cant say I have heard of anyone using copper for the service entry and I haven't heard of anyone having problems with the aluminum either.

As to mixing copper and aluminum, there are special connectors for that. Thay will say AL/CU rated on them. It also helps to use some antioxidation paste on them also. Ask you electrical supply house and they will show you what stuff to use.

As to connections coming loose, I like to tighten them down real tight with the paste on them and come back once an hour for about three or four hours and retighten them or until they dont turn any more.

Mac_Attack · #7 07-12-2007, 07:40 AM

In Mich we use Alu for our service entrance cables. As TBD said use the no ox paste and tighten them down. If you have the money go with the copper. Billy Mac ;D

tsubaki · #8 07-12-2007, 08:24 AM

I'm sure you are useing 4 wire (2 hots,neutral and ground), being it's a subfeed panel. Also the distance on the 150ft feeder may need to be upped one wire size.
Cu or AL shouldn't be any problem being it's in conduit. Copper is going to be better all the way around.
Either wire type used do coat the ends with Noalox, you will be glad later.*

Stinky_Hooker · #9 07-12-2007, 11:40 AM

I use direct burial 100 amp aluminum mobile home feed around here and it works well. During my days running an electrical truck we did as well. I have some running my shop at home (just over 100') and it has been underground for just over 8 years now with no problems.

THEFERMANATOR · #10 07-12-2007, 11:42 AM

My wiring is going to be off of a 200 amp main panel located by my wells. I'm going to be making 4 runs off of it, 2 will be going to my 2 wells and the other 2 will be going to my shop and trailer. They will be 4 wire runs(2 hots, neutral and bare copper ground) inside of SCH40 conduit buried(local building department said I have to use conduit for a sub-panel), nothing really complicated. The actual feeder to my 200 amp panel will be 2 4/0 pieces of aluminum and a piece of 3/0 for the neutral since the local power company uses aluminum wire in there overhead runs. I've just heard to many people talking about ALUMINUM breaking inside of the conduit because of heating and cooling expansion. Just looking for advice on it. I personally want to run copper, but $1K a roll is a steep price tag.