Al vs Cu.......are they equal?????? Which do you prefer and why?????

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ActionDave

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Their knowledge is based off past jobs. They don't install anything but yet see the end results in the field to make the decision to spec something or not.
My kids were always way better at paying attention to the number of times I was late with their allowance even though I was on time most every week.

Terminations would be my primary concern in aluminum feeds when under heavy load. The constant heat cycles will loosen the connection over time.
Have you ever given thought to the number of Al connections in service for decades, many, many of them over fifty years?
 

big john

Senior Member
Location
Portland, ME
...A lot of splices in substructures, spent a wet winter submerged, and powered. they megger fine....
It sounds like you went the extra mile to do good work in a harsh environment and I think aluminum will work fine when carefully installed.

But to be sure, a megger isn't gonna demonstrate a poor conductor termination. You would need offline contact-resistance tests, or else an infrared survey under full load.
 

user 100

Senior Member
Location
texas
Qualified personnel, Isn't that what we are as electricians?


And not all electricians are knowledgeable about how to install al.:)

As said above the smaller solid sizes of the poorly terminated old stuff is what primarily gave/gives you issues. A lot of the stuff about al is overblown - it's not unusual to see an old al range ct thats trouble free. Even most bare transmission lines contain a high aluminum content and they plug along decade after decade.
 

kwired

Electron manager
Location
NE Nebraska
I had two different service calls in the past 3 or 4 days where copper conductor terminations failed. I presume neither one was properly tightened to begin with.
 

JoeyD74

Senior Member
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Boston MA
Occupation
Electrical contractor
My kids were always way better at paying attention to the number of times I was late with their allowance even though I was on time most every week.

Have you ever given thought to the number of Al connections in service for decades, many, many of them over fifty years?

The biggest difference in your analogy is your kids probably didn't cost you future work because you tried to save money. If a job has issues it will end up back on the engineer so I understand their thinking, spec copper because any electrician can install it with little chance of problems down the road.
 

peter d

Senior Member
Location
New England
If a job has issues it will end up back on the engineer so I understand their thinking, spec copper because any electrician can install it with little chance of problems down the road.

I abhor this principle. We should never dumb the trade down to the lowest common denominator simply because there are bad electricians out there. Most of us are professionals and we're capable of installing aluminum conductors within its listing and installation requirements. And any electrician who has been in the trade long enough has seen plenty of failure with copper terminations. Most failures can be traced back to poor installation.
 

ActionDave

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The biggest difference in your analogy is your kids probably didn't cost you future work because you tried to save money. If a job has issues it will end up back on the engineer so I understand their thinking, spec copper because any electrician can install it with little chance of problems down the road.
I agree with iwire. I question their knowledge. There are a ton of specs based on bias rather than the real world. It's a good sales angle for the right customer.
 

JoeyD74

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Boston MA
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I agree with iwire. I question their knowledge. There are a ton of specs based on bias rather than the real world. It's a good sales angle for the right customer.

Most decisions are made on opinion, this just happens to be theirs.
 

JoeyD74

Senior Member
Location
Boston MA
Occupation
Electrical contractor
I abhor this principle. We should never dumb the trade down to the lowest common denominator simply because there are bad electricians out there. Most of us are professionals and we're capable of installing aluminum conductors within its listing and installation requirements. And any electrician who has been in the trade long enough has seen plenty of failure with copper terminations. Most failures can be traced back to poor installation.

If their decision to avoid aluminum conductors because of past issues what do you do? They don't install in and have zero control over its install. You can write specs and procedures until your blue in the face, if they don't get followed its no good.
 

iwire

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Location
Massachusetts
If their decision to avoid aluminum conductors because of past issues what do you do? They don't install in and have zero control over its install. You can write specs and procedures until your blue in the face, if they don't get followed its no good.

I tend to doubt they had issues.

Been doing service work for a lot of years now and I see copper failures as often as aluminum failures.

Then there is the fact that Big John brought up, most of our electrical distribution systems in the US are aluminum, outside in the weather and I will add often run through much greater temperature / loading cycles than our building wiring.
 

Fulthrotl

~Autocorrect is My Worst Enema.~
It sounds like you went the extra mile to do good work in a harsh environment and I think aluminum will work fine when carefully installed.

But to be sure, a megger isn't gonna demonstrate a poor conductor termination. You would need offline contact-resistance tests, or else an infrared survey under full load.

understood. i was more interested in how that heat shrink worked
when submerged in water. i've got few concerns about swaged
wire terminations.
 

JoeyD74

Senior Member
Location
Boston MA
Occupation
Electrical contractor
I tend to doubt they had issues.

Been doing service work for a lot of years now and I see copper failures as often as aluminum failures.

Then there is the fact that Big John brought up, most of our electrical distribution systems in the US are aluminum, outside in the weather and I will add often run through much greater temperature / loading cycles than our building wiring.

Why spec it then if there was no issues? They don't sell it or install it, so what do they gain?
 

user 100

Senior Member
Location
texas
understood. i was more interested in how that heat shrink worked
when submerged in water. i've got few concerns about swaged
wire terminations.

I think some of the Panduit hst is rated for wet,but understand about wanting to double check.
The port out that way restricting use of al was probably due to unfounded concerns about corrosion, no?

Big thing is you did a good and cost effective installation.:)
 

infinity

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New Jersey
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Journeyman Electrician
Our jobs specs always call for copper. I've installed aluminum risers once in 30 years. Copper is more expensive and therefore provides more dollars for the boss on the material markup. One of the good things about aluminum is you won't come to work on Monday morning and find all of your reels of aluminum wire missing. IMO aluminum is fine but I would use crimped on terminals ins lieu of mechanical lugs.

I'm still trying to figure out why you crimp on aluminum adapters like the ones in the photo. :?
 

Fulthrotl

~Autocorrect is My Worst Enema.~
I think some of the Panduit hst is rated for wet,but understand about wanting to double check.
The port out that way restricting use of al was probably due to unfounded concerns about corrosion, no?

Big thing is you did a good and cost effective installation.:)

actually, i think they were pretty well founded concerns about corrosion.

a swaged connection is fused in such a way that it's effectively not separate
material any more. that leaves any moisture in the connection to be a concern.
by the time that heat shrink is fully collapsed, that connection is hot enough
that there is no moisture anywhere around it.

the problem otherwise, is that you have a setscrew that can loosen over time,
and moisture that can wick into the aluminum, and corrode it over time.
the drawback with field installation, is that a setscrew lug is UL listed, but
setscrews can, and in my experience often do loosen up over time.

i don't use setscrew lugs for either copper or aluminum any more.
just a personal preference on my part, but it seems that i'm not alone in
this... milwualkee is now making crimpers.

burndy may have to get their pricing policies under control.

https://www.milwaukeetool.com/power-tools/cordless/2679-22
 

user 100

Senior Member
Location
texas
actually, i think they were pretty well founded concerns about corrosion.

a swaged connection is fused in such a way that it's effectively not separate
material any more. that leaves any moisture in the connection to be a concern.
by the time that heat shrink is fully collapsed, that connection is hot enough
that there is no moisture anywhere around it.

the problem otherwise, is that you have a setscrew that can loosen over time,
and moisture that can wick into the aluminum, and corrode it over time.
the drawback with field installation, is that a setscrew lug is UL listed, but
setscrews can, and in my experience often do loosen up over time.

I meant unfounded as in excessive concern. I can definitely see where they would be worried esp w/ terminations or anything exposed in that type of environment- apparently for cost sake, the bean counters realized there are effective ways of accommodating this less expensive conductor- specs are everything until somebody makes an informed decision and decides they won't pay for them.

As for swaged vs. sc, I think a lot of it has to do w/ the initial installation- a huge problem w/ al is improper torquing as Peter d mentioned above- often the connection is doomed from day one and will eventually fail b/c someone decided to "flatten" instead of merely terminate.
 
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JoeyD74

Senior Member
Location
Boston MA
Occupation
Electrical contractor
I was just reading up on some terminations and they all show tell you to wire brush or rough sand the wire end before crimping or terminating or putting no lox on it.
Is anyone doing that?
 
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