Copper vs aluminum service entrance conductors

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I am going to be installing a 200 amp residential service, having about a 200' run from the meter to the panel. Any thoughts on using aluminum XHHW versus copper? The conductors will be in conduit. Thanks.
 

Jon456

Senior Member
Location
Colorado
I am going to be installing a 200 amp residential service, having about a 200' run from the meter to the panel. Any thoughts on using aluminum XHHW versus copper? The conductors will be in conduit. Thanks.
I assume you're going to bury the conduit. Aluminum is less expensive, but you need to go up in gauge to handle the current (compared to copper); that probably means larger conduit too. Copper is much more expensive (and a whole lot heavier) than aluminum.

For me, the biggest advantage of copper over aluminum is corrosion resistance. Ideally, there should never be any corrosion. But we recently pulled some buried-in-conduit aluminum feeders that had damage to the XHHW from the original installation. The aluminum conductors inside had corroded, swelled up like a fat sausage, and separated. Copper would not have done that.
 

Jon456

Senior Member
Location
Colorado
Here's some photos to illustrate what I'm talking about:

IMAG1516.jpg


IMAG1520.jpg


IMAG0163.jpg


IMAG0161.jpg
 

Cow

Senior Member
Location
Eastern Oregon
Occupation
Electrician
You have to take Jon456's pics with a grain of salt. That work was done by hacks if it's the same installation that has been posted in thread after thread on this forum.

I would have no problem using aluminum but we use USE insulation just because it's direct bury rated insulation. That makes it a little tougher in my mind than XHHW.
 

Fulthrotl

~Autocorrect is My Worst Enema.~
I am going to be installing a 200 amp residential service, having about a 200' run from the meter to the panel. Any thoughts on using aluminum XHHW versus copper? The conductors will be in conduit. Thanks.

depends on how it's terminated.
the wire is fully serviceable, and the insulation is the same as copper insulation.

the only way i'll terminate aluminum feeders is with a hypress.
then i use a UL approved direct burial heat shrink 600 volt material
to seal the hypress to the insulation.

to land on breakers, i'll use a finger lug hypressed onto the wire. if there isn't room
on the breakers for finger lugs, and there sometimes isn't, i'll go a foot away from
the breaker, and hypress a butt splice onto the aluminum, changing to copper of
the same guage, and land THAT on the breaker.

i've never had an aluminum wire failure when doing it this way, in 35 years.

with setscrew lugs, the wires fail at regular intervals..... :-/







 

iwire

Moderator
Staff member
Location
Massachusetts
the only way i'll terminate aluminum feeders is with a hypress.
then i use a UL approved direct burial heat shrink 600 volt material
to seal the hypress to the insulation.

to land on breakers, i'll use a finger lug hypressed onto the wire. if there isn't room
on the breakers for finger lugs, and there sometimes isn't, i'll go a foot away from
the breaker, and hypress a butt splice onto the aluminum, changing to copper of
the same guage, and land THAT on the breaker.

i've never had an aluminum wire failure when doing it this way, in 35 years.

Yeah, anyone can through time and money away, there is no trick to it.:D

with setscrew lugs, the wires fail at regular intervals..... :-/

That is just nonsense.
 

Fulthrotl

~Autocorrect is My Worst Enema.~
Yeah, anyone can through time and money away, there is no trick to it.:D



That is just nonsense.

and anyone can do a half assed job, there is no trick to it.

as for throwing time and money away, the AHJ of the location of that install does NOT
permit aluminum feeders. until now, terminated in that wasteful fashion you laughed at.

first job i did this way, the delta between copper and aluminum feeders was about $120k,
the second job, the delta was about $150k.

the lugs and heat shrink were about $2k for the entire job.

do the math.
 

Jon456

Senior Member
Location
Colorado
You have to take Jon456's pics with a grain of salt. That work was done by hacks if it's the same installation that has been posted in thread after thread on this forum.
Our first set of aluminum feeders were from the original facility construction ~15 years ago. We pulled them out as part of the solar project and discovered damage to one of the aluminum neutrals (there were four parallel sets of feeders) and one of the aluminum EGCs. The EGC had literally dissolved to the point where it had completely separated.

We replaced the damaged wire with new aluminum. Then, the hacks who were installing our new solar system damaged the wires again when they pulled it back in resulting in a total short several months later. The hacks who installed our solar were not the same contractors who installed the original feeders 15 years ago.

So two sets of aluminum feeders, installed by two different electrical contractors, ~15 years apart, and both had damage to the insulation that led to the aluminum rapidly corroding and failing.

I agree that if the wire is installed correctly, then aluminum wire will be just as serviceable as copper. I just wanted the OP to be aware of how quickly and badly aluminum can fail if it is not installed correctly.
 

Cow

Senior Member
Location
Eastern Oregon
Occupation
Electrician
and anyone can do a half assed job, there is no trick to it.

I'm a little surprised that'd you say anyone who uses set screws on aluminum wire is half assing it. I take pride in my work, I also don't think hypressing lugs on the ends and then covering it in heatshrink is the ONLY way to go. I guess since you've been doing it so long this way, I can only assume you are stuck in your ways.

I haven't been doing it 35 years, it's only been 11 for me, but I've seen A LOT of older installations with no issues with plain old set screws. And I've yet to go back on any of mine.

Keep doing what you're doing if it makes you feel good, but I don't see any reason to call the rest of us out just because we don't do it your way. I'm willing to wager there are millions more installations with set screws than crimps and I don't see these installations burning up left and right all around me.
 

11bgrunt

Pragmatist
Location
TEXAS
Occupation
Electric Utility Reliability Coordinator
4/0 aluminum under hex lugs was the norm for a 200 amp residential service before I started in '80.
I have preached that if the Al conductor is sized correctly, cleaned, anti-ox paste used, terminations torqued correctly and that job will be as good as the same job with Cu.
Cu leaves enough room that almost anyone can install Cu with no problems. I have seen many customers with a copper bias because aluminum conductors are evil in their mind. IMO, most of that copper only mentality is from solid conductors used inside the wall in the '70s. THAT was a bad idea.
I would use Aluminum service entrance installed in conduit on my Mother's house.
 

Fulthrotl

~Autocorrect is My Worst Enema.~
I'm a little surprised that'd you say anyone who uses set screws on aluminum wire is half assing it. I take pride in my work, I also don't think hypressing lugs on the ends and then covering it in heatshrink is the ONLY way to go. I guess since you've been doing it so long this way, I can only assume you are stuck in your ways.

I haven't been doing it 35 years, it's only been 11 for me, but I've seen A LOT of older installations with no issues with plain old set screws. And I've yet to go back on any of mine.

Keep doing what you're doing if it makes you feel good, but I don't see any reason to call the rest of us out just because we don't do it your way. I'm willing to wager there are millions more installations with set screws than crimps and I don't see these installations burning up left and right all around me.

and obviously, they aren't burning up all around. i was just pissy at
iwire's snarky response, for what thats worth, and was snarking back.

i've seen a fair amount of setscrew lugs that have loosened up,
and turned a leg on a large molded case breaker into a crispy critter.
aluminum seems more problematic that copper in this respect.
i've never seen a hypress fail.

normally, just taping up where the lug crimps on, to keep moisture
wicking up into the strands is all i do. but this is a salt water environment,
and tape doesn't have a UL direct burial listing, and the panduit heat shrink
does. normally, it'd be scotch 33, and finish it up. the panduit is slow, and
triples the make up time. scotch cold shrink is way faster, but about $30
or more a splice, the cost / benefit doesn't work.

so, don't get all sensitive on me, nothing you've ever written says you are
anything but a good mechanic.

woo hoo for bob. instead of just ignoring him, i got snarky. +1 for bob.
 
so, don't get all sensitive on me, nothing you've ever written says you are
anything but a good mechanic.

I dont know if there is some sort of inside joke there but if not I dont think that is called for. I dont want to get into a pissing match but honestly I found Iwires and Cows responses very reasonable. I think someone starting out who doesnt have a lot of experience could get the wrong idea from your post on Cu vs AL and how to terminate it. I think your views and methods on the subject are quite far to the right/left of average.

I dont recall ever seeing a failed aluminum termination. I personally rarely use copper larger than #3. I have seen many failed direct bury AL conductors, but Ill bet if copper was direct buried I would have seen that fail too. Even a small knick in the insulation will result in current flowing to ground and if its wet you will have electrolysis happening and breaking down the water into oxygen every half cycle and that quickly oxidizes the material. I did an experiment in high school where I used a pad lock for the negative electrode and was able to pretty much dissolve it in a few hours.
 

templdl

Senior Member
Location
Wisconsin
Also, would there be a possibility that a smaller conduit could be used with copper conductor since the wire size would be smaller with a given ampacity?
 

MasterTheNEC

CEO and President of Electrical Code Academy, Inc.
Location
McKinney, Texas
Occupation
CEO
I am going to be installing a 200 amp residential service, having about a 200' run from the meter to the panel. Any thoughts on using aluminum XHHW versus copper? The conductors will be in conduit. Thanks.
Well...being that we manufacturer both CU and AL I will tell you this much. With todays Series 8000 blend it is now simply a matter of choice at this stage of the game. While I am CU man at heart I can tell you I would have ZERO fears in using AL for any code compliant application as long as you know how to dress it and terminate it properly.

Anything can fail but when installed correctly....the chances are no greater for AL than CU.
 
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