Aluminum versus Copper

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charlie b

charlie b

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Almost every client I encounter has a set of company-specific design standards that forbid the use of aluminum wire. Almost every Value Engineering Review I encounter includes the suggestion of substituting AL for CU as a cost-saving measure. Almost every time that suggestion is made, the owner rejects it.

I am in the middle of just such an exercise now. The owner is a private company that has no design standards of its own. The facility is a large factory that will have a boat load of wire, so the cost differences will be significant. I have two questions:
  1. Are there any advantages and disadvantages of AL wire that I should bring to the owner?s attention?
  1. Has anyone designed or constructed a large facility lately, using all AL wiring, and if so do you have any lessons to share?
 
charlie b said:
Almost every client I encounter has a set of company-specific design standards that forbid the use of aluminum wire. Almost every Value Engineering Review I encounter includes the suggestion of substituting AL for CU as a cost-saving measure. Almost every time that suggestion is made, the owner rejects it.

I am in the middle of just such an exercise now. The owner is a private company that has no design standards of its own. The facility is a large factory that will have a boat load of wire, so the cost differences will be significant. I have two questions:
  1. Are there any advantages and disadvantages of AL wire that I should bring to the owner?s attention?
  1. Has anyone designed or constructed a large facility lately, using all AL wiring, and if so do you have any lessons to share?
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The only big difference from a safety I can remember about Al vs. Cu is creep. And that can be avoided by using appropriate terminations and devices or Cu. pigtails.
 
We most always had the rejection as well but when used it did not present problems tho we used it only for really big wire 500 and up when we used it.The smaller sizes would have a higher fracture ratio tho that could have been a heavy hand on the end of the tool.This was long ago and a lot of details have gone astray.One other thing most of our work was coastal in location so a salt water atmosphere may have played a role ,don't recall.

dick
 
charlie b said:
Almost every client I encounter has a set of company-specific design standards that forbid the use of aluminum wire. Almost every Value Engineering Review I encounter includes the suggestion of substituting AL for CU as a cost-saving measure. Almost every time that suggestion is made, the owner rejects it.

I am in the middle of just such an exercise now. The owner is a private company that has no design standards of its own. The facility is a large factory that will have a boat load of wire, so the cost differences will be significant. I have two questions:
  1. Are there any advantages and disadvantages of AL wire that I should bring to the owner?s attention?
  1. Has anyone designed or constructed a large facility lately, using all AL wiring, and if so do you have any lessons to share?
Click to expand...

Here is a link that may be of interest on along these lines: http://www.cable.alcan.com/NR/rdonlyres/5606828B-C55C-488F-8F53-28E1BC2A3AB8/0/CopperCableTheft.pdf
I think that the AL cable/conductor industry still is trying to shake off the stigma associated with AL conductors of 30+ years ago. IMO the alloys used today are vastly improved over the early days and AL conductors are fine. There are a number of white papers on AL conductors and terminations out there explaining the state of things today that make a good case for using AL.
 
My understanding is that the NEW ALUMINUM (manufactured today) does not have the problems that it did years ago. It is made of a different alloy that will not expand and contract the way the old aluminum wire had done.

That being said I would still rather work with copper as IMO since it is usually a smaller size it is easier to deal with. Of course aluminum compact conductors can make a big difference but there may be an added expense as most terminal, I do believe, are not rated for compact conductors.

I think the fear of aluminum from the past is going to be very hard to overcome. Cost is about a third for aluminum so that could be a big plus.
 
With the introduction of AA-8000 aluminum, most of the problems have been eliminated as long as proper terminations are also selected. Even before, I wouldn't hesitate for conductors #1 and above - again with the qualification of selecting proper terminations.

Oddly enough, in some refinery operations copper can be eaten alive by hydrogen sulfide - even when it is well below explosive or toxic levels.
 
Most terminations are dual-rated for copper and aluminum conductors. I'll generally specify copper and allow the Owner to make the decision for the VE alternative to aluminum.

I will not allow aluminum for feeders less than 100 amps and terminated at vibrating loads or medical imaging equipment.

I've seen a lot of aluminum installations, and as long as they follow installation procedures (wire brushing of terminations, anti-oxidation compound, proper torquing), there hasn't been any issues.
 
The project site is in the northeast US. There is an ocean not far away, and the temperature ranges from -15 to +100. The service transformers are 2500 KVA at 480V, and there are a number of 500+ amp loads, so there will be some large wires involved.

What is meant by "proper terminations," and what do I need to tell the contractor (the one who is suggesting an all-AL installation)?
 
Long Island has a long history of AL failure.. it is what it is and I have never had a customer ask for AL over CU..

Even the POCO guys I ask tell me AL keeps them busy with overtime..

Everything these days is "new and improved" if you believe the hype put out by the manufacture...

But when AL fails.. it makes the installer look bad for using it in the first place.. not fair I know...

Someone or something has to be blamed when it cost a company $$$$$$$$$$ in repairs...

Sure it saves money up front.. but what about when and if it fails down the line??
 
B4T said:
Long Island has a long history of AL failure.. it is what it is and I have never had a customer ask for AL over CU..

Even the POCO guys I ask tell me AL keeps them busy with overtime..

Everything these days is "new and improved" if you believe the hype put out by the manufacture...

But when AL fails.. it makes the installer look bad for using it in the first place.. not fair I know...

Someone or something has to be blamed when it cost a company $$$$$$$$$$ in repairs...

Sure it saves money up front.. but what about when and if it fails down the line??
Click to expand...

I'm curious if this is the EC-1350 aluminum allow or the AA-8000 that is experiencing failures? In my area, the utilities pretty much use the 8000 aluminum alloy exclusively for underground feeds from the utility transformers to the CT cabinet / main switch board and for residential feeds to homes.

I'd be very curious to know if people are experiencing failures with recent aluminum installations.
 
Shoe said:
I'm curious if this is the EC-1350 aluminum allow or the AA-8000 that is experiencing failures? In my area, the utilities pretty much use the 8000 aluminum alloy exclusively for underground feeds from the utility transformers to the CT cabinet / main switch board and for residential feeds to homes.

I'd be very curious to know if people are experiencing failures with recent aluminum installations.
Click to expand...

I really don't know..
 
charlie b said:
The project site is in the northeast US. There is an ocean not far away, and the temperature ranges from -15 to +100. The service transformers are 2500 KVA at 480V, and there are a number of 500+ amp loads, so there will be some large wires involved.

What is meant by "proper terminations," and what do I need to tell the contractor (the one who is suggesting an all-AL installation)?
Click to expand...

I know that aluminum does not do well at the ocean but indoors it should be fine. Proper termination just means that the terminals are suitable for the aluminum. Most termination are rated co/al so that should not be an issue unless you use compact conductors. I still use the anti oxidant (No-alox) even though it isn't necessary according to the manufacturer.
 
I have repaired as many failed low voltage CU connections as I have AL. I would limit the AL to panel and equipment feeders 100 amps and above and shy away from any AL motor feeders.

As for MV applications I have seen very few failures with CU or AL and 99.9% of them were due to poor termination practices.
 
I ALWAYS spec out HI-Press lugs for any and all AL wiring.

The worst experance I had with AL wiring was when I specd 3/0 AWG for a 200 A feeder. The EC installed 3/0 AL because he said that AWG stood for AL Wire Gauge:happysad:
 
AL & IR

AL & IR

Does anyone require periodic thermo inspections? A friend owned a medium-large ISP [when there were ISP's] in a 1930's era office building. Originally, it had two 15A outlet circuits per floor; needless to say he had multiple upgrades.

His insurance company required every breaker panel have a thermogram annually. First it was AL but then all types.

[The building had ~60% of its ft^2 rented by communications companies. This showed not just in power demand/generator footprint, but reduced water usage, elevator loads and even floor wax. They decommissioned one of the elevator shafts for conduit use but it soon filled up...]
 
520 Bridge

520 Bridge

charlie b said:
The project site is in the northeast US. There is an ocean not far away, and the temperature ranges from -15 to +100. The service transformers are 2500 KVA at 480V, and there are a number of 500+ amp loads, so there will be some large wires involved.

What is meant by "proper terminations," and what do I need to tell the contractor (the one who is suggesting an all-AL installation)?
Click to expand...

If it makes you feel any better, all the temp power for the 520 Bridge replacement has gone in as AL, that Tacoma (on SW), Kenmore (on FW) and at the East high rise (Medina, FW). We have not had any problems in the last year that we gave installed.:)
 
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