janagyjr

Definitely worth learning about in case of working on older homes, but does anyone actually use aluminum conductors on new work these days? If so, is it just because of the relative cheapness of Al (I would figure though that it would be offset by having to buy the larger conductor sizes to get the necessary ampacity ratings)? It doesn't seem easier to work with, having to use an inhibitor to prevent oxidation at the connection point. Plus you have to figure for creep, strength, etc.

I'm asking because in Chapter 4 of the EWR textbook, there is a whole section devoted to aluminum conductors (which encompasses about 3 dozen or more paragraphs over 3 pages (along with tables and charts and diagrams)).

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Shockdoc

I use Al on services on Long Island. Local codes restrict Al to only services and in some town jurisdictions they even require mac adapters on the terminations. Copper is nice but way overpriced. Al is safe and reliable when terminated properly. I tend to avoid split bolts for Al splices, the utility co. supplies featherbox connectors, I use themfor all troft Al splices, more cross sectional contact.

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oliquir

just check pricing of CO/ALR devices and it will eat the difference of price between alu and copper

janagyjr

Everything I'm reading so far seems to be the case, restricted to use in services now-a-days.

Mac adapters? Featherbox connectors? I googled the latter and couldn't find anything useful.

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backstay

Used in services and feeders, most if not all panels are cu/al rated, so no price increase there. Most suppy houses around here don't carry service feeders in copper. Here is my price differance for a 200 amp res service

CU-$7.87/ft had to build this out of single conductor, supply house didn't carry triplex copper.
AL-$1.75/ft

janagyjr

I was more curious about using Al for branch circuits, though. If there is no benefit (copper is better, has less issues, switches and receptacles are generally made for them unless otherwise listed, etc.), why still use Al (if it is still used in branch circuits) at all?

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backstay

Ahh...no, don't us AL for branch circuits. I don't have my code book in front of me but that went out with the fires it caused in the 70's. When I find AL in the walls, I rip it out! If you ever have to deal with aluminium at devices or at the breaker, what you see is they tend to break with little bending. Oh and 12/2 nmb is just below 40 cent a foot

janagyjr

I get the impression it is allowed, just have to use a larger AWG due to ampacity. I don't have the 2k8 book in front of me right now (getting ready to head out on a date with the fiancee), though. I'll read up on it, but that's a big 10-4 on not using it for branch circuits.

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knowshorts

I just bought a 1000' reel of 4c 1/0 alum. Cost 4k. Copper would probably been well over 15k.

I've seen al/cu outlets at HD for like $1.25 each. I don't believe they are TR. But cheaper than purples.

It doesn't make cent$ to pull copper feeders now unless it's spec'ed.

backstay

334.104 Conductors
The insulated power conductors shall be sizes 14 AWG through 2 AWG with copper conductors or sizes 12 AWG through 2 AWG with aluminum or copper-clad aluminum conductors.

Vintage Sounds

We roughed in 6/2 AL NMWU for the central A/C condenser in the townhouse units I'm currently working on. Seems like a good idea, way cheaper than equivalent copper for a four story vertical run. For that matter I wonder why it's not more popular to use 6/3 AL for kitchen range receptacles instead of 8/3 CU. The receptacle is AL/CU rated anyway and 8/3 copper is expensive/heavy/annoying.

Mike in Canada

I just finished an 800A run of tandem 350kcmil aluminum. The run was about 400' long. If I'd done it in copper I could have used 250kcmil, but the copper would have been way heavier and more expensive. The aluminum was less than a pound per foot, so we were able to pull it into place by hand.

For services, particularly long runs, aluminum is very nice. It's irritating to have to make sure the lugs are dual-rated, and it's irritating to make sure you have noalox on hand, but other than that it's all good.

janagyjr

So for services and where the wire is already going to be rather large gauge, Al is more feasible, but not really for branch circuits?

*nods and ponders* Thanks guys. (:

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hardworkingstiff

Are you able to purchase AL in 12/2 and 10/2 ? I sure would hate making up devices in a kitchen with 10/2 even if it is AL.

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jwjrw

I'm doing a really ugly seu 200 amp service upgrade today. The seu will bend around the corner and go up to get my 12 ft required clearance. I will be feeding main breaker with 4/0 xhhw-2 al also.

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BBQ

I think 8 AWG is the smallest AL available right now.

BBQ

I do not think you realize how much of a price difference there is.

Lets say you need to run a 100' long, three phase, four wire 400 amp feeder.

In AL the conductors will cost me about $820. (750 Kcmil THHN)

The same job done in copper the conductors will cost me $3,950 (500 Kcmil THHN)

Then you have not worked with much big wire, it is much easier to work with.

That is a good idea but not required by the NEC unless the manufacturer requires it. Either way it is easy to do.


I don't know what you mean. You torque the connector to the correct amount and go home.

Consider this, the overwhelming majority of power company conductors are AL and are in locations exposed to the elements.

kevmanTA

I like using Aluminum conductors in Teck cable, we do it when the customer wants a cheaper price compared to copper in conduit

Just don't forget the noalox..

qckrun

About to possibly install over 4000ft of 350XHHW-2 MV aluminum cable for a 21kv service from the local utility.

qckrun

Job I am on local utility is pulling 1100aluminum in.