Electricians in the house? Copper vs AL exterior commercial

[YY1]

A couple of years ago, I paid a contractor to replace a 100A Zinsco main breaker box and re-feed a 60A sub panel at my shop.

They did good work, using a Square D panel and weather tight compression 1" EMT.

Now I find I need to move the sub panel about 15 feet.

I was surprised to find they used #4 aluminum wire.

Why wouldn't I want #6 copper?

I know the feed from the utility is aluminum.

Is there something about exterior runs?

BTW, I'm thinking about moving the sub panel to the interior of the building.

I don't think there's any issues with that, are there?

 

[727]

Copper is better just cost more $$
Aluminum works ok as long as you don't knick the insulation and be sure to use the anti-corrosion sealer on the end connections

 

[BeepBeepRR]

Its just cheaper.. They can also use triplex which is aluminum with a neutral and a ground. The cost is higher for copper. Copper is better in my opinion and aluminum well, has its issues that come with it. Ask anyone that lives in a old mobile home with aluminum wiring. The heating of the AL wire is just terrible. And thus not safe in those old trailers.

 

[Budnicks]

calling @kiwigtx

 

[747mopar]

As mentioned it's cheaper, simple as that. The problem with aluminum is it grows and contracts much more resulting in loose connections plus corrodes over time. Because it's terminated in clamps at both ends it's usually perfectly fine for service runs as long as you use an anti corrosion lube on it. I've got aluminum service wire on both garages, my home and our woodshop and never had a problem.

 

[Glenwood]

Aluminum is fine. Most power lugs are alloys that can terminate copper or aluminum. Noalox keeps oxidation in check for connections.
A major problem with aluminum branch wiring are the devices it terminates to. When people started replacing switches and receptacles, the terminals were often not rated for aluminum. Dissimilar metals caused corrosion which added resistance leading to heat and eventually fire.
Nothing wrong with feeder wiring being aluminum imo, but not a fan of branch wiring.
If the sub is going inside just make sure your local codes are followed.

 

[YY1]

Looks like about $150 to do this if I use #6 copper and a #8 ground.

I can do that.

I could have swore I saw AL prices the first time I searched Lowes but now I don't.

We used to use "NoAlOx" on AL connections.
(I see someone posted that as I was typing)

I was an electrician apprentice for 2.5 years and then 5 years in building maint.

 

[Mike67]

Problem with Al is like 747 said is it expands more than copper which loosens the connectors. Plus it will oxidize. .
Just need to make sure your lugs are rated for both Al/Cu anytime you use Al, that goes for outlets, switches wire nuts ect.
I always use an anti oxidant like NoAlox.

 

[YY1]

Looks like I'll be replacing a 20 ft run of #4 Al with a 35 ft run of #6 copper.

Should be easier to pull.

 

[BeepBeepRR]

Do you have ground rods at your garage? If not Id probably install one. But thats just me.

 

[beanhead]

These guys have pretty much nailed it... Aluminum is fine, it will just be be up-sized for ampacity per NEC compared to copper. The utility companies use it. As long as the termination lugs are rated for it, and they used some 'noalox' compound it's okay(you didn't get shafted!) As far as moving your sub panel inside, if you can do it, do it. It's always better to have that stuff inside protected from the elements as much as possible.

Oh, and..

...to replace a 100A Zinsco main breaker box...

That's the best thing anybody can do! Zinsco panels are horrible...

 

[Lefty71]

Aluminum is ok for services. Just take the needed precautions, lube ends, expansion sleeves set mid-point, leave slack, don't skimp, etc. Since it's cheaper, go up a size, and you'll do just fine. Don't ever be tempted to go with aluminum in the smaller sizes like regular romex though. There were a lot of fires in the 70's, we learned that lesson as a society. BTW, fine wire copper is the cats meow (forget the actual type) but's it really high dollar. Just consult a sizing table and jump up one, you'll do great. And you already know, stick with Square D QO style mains and breakers. They are the world standard, and you'll always be able to get parts. HTH, Lefty71

 

[mopar 3 B]

Looks like I'll be replacing a 20 ft run of #4 Al with a 35 ft run of #6 copper.

Should be easier to pull.

A little wire lube and it pulls even better.

 

[YY1]

IIRC I once pulled four #6 and an 8 ground 250 ft in 1" conduit with a double offset in the middle and a 90 at each end.

That was NOT fun.

I begged the guy that was running the job to break it in the middle and add more soap.

Problem was it was 35' up on the wall.

We finally did and pulled to the break, then to the end.

8 Hours to pull that after 2 hours to run the pipe.

 

[moparmarks]

Aluminum when installed and terminated correctly will out last all of us. Can be used most any where except hospitals and branch circuits.
If you have the doe and it will make you sleep better at night then use copper.

 

[moparmarks]

Try pulling 4-#500mcm copper 700' through 4 boxes up 11 stories, one shot. Didn't do it by myself of course. Had a little help. Gotta love large hospital work.

 

[beanhead]

IIRC I once pulled four #6 and an 8 ground 250 ft in 1" conduit with a double offset in the middle and a 90 at each end.

That was NOT fun.

I begged the guy that was running the job to break it in the middle and add more soap.

Problem was it was 35' up on the wall.

We finally did and pulled to the break, then to the end.

8 Hours to pull that after 2 hours to run the pipe.

I would have fired the whole crew (foreman first!)

 

[BeepBeepRR]

Try pulling 4-#500mcm copper 700' through 4 boxes up 11 stories, one shot. Didn't do it by myself of course. Had a little help. Gotta love large hospital work.

Pulled 350 foot of 500 MCM and it was 50 feet short.. Spent all day half hitching that **** back out.. The foreman got fired for messing up the measurement.. And having 4 guys pulling that **** back out all day.

 

[747mopar]

I learned a cool trick at work that I use often now when running long conduit runs. I had ran a ton of rigid in preparation for an install when the plant manager came by and asked why I didn't use compressed air vs a snake... he explained and I seldomly ever use a snake now. Takes a little practice but I've blown pull strings threw 200ft of rigid in seconds using a simple blow gun.

 

[Mike67]

Try pulling 4-#500mcm copper 700' through 4 boxes up 11 stories, one shot. Didn't do it by myself of course. Had a little help. Gotta love large hospital work.

We always fed down....too dangerous puling up with that ammount of weight....had two people on each reel, chocks at first few j boxes.
Came in after another crew let one go down 10 stories....very lucky it didn't kill the guy working the tugger....destroyed the vault...