good material thanks

Very efficiently written article. It will be helpful to anybody who utilizes it, as well as myself. Keep doing what you are doing - for sure i will check out more posts.

I have had good life (30+ years) out of aluminum wiring for medium (13.8kv, 4160v, 2300v) and low voltage (480v) power distribution wiring. I would not recommend the use of aluminum wiring for 120 volt distribution in residential, office buildings, or in machine control wiring. As to the concern for IR surviellance, it is a valid point, switchboards and cable connections should be IR surveyed at least yearly, but this IR survey requirement also applies to copper. I have not had any more problems with aluminum wound transformers than copper wound,

A couple points - I'd like to see the CDA respond to the points presented; I understand that welding of aluminum (as in a pad mount transformer coil, for example) is not a perfected process, and prone to failure; As the electrical cost of new construction is somewhere between 5 and 10% of the total cost, what is the real savings by using AL in a few locations - 1%? less? Manufacturers have a vested interest in AL - it's lighter (=less handling cost), cheaper (= greater margin) and generally easier to machine (= less machining cost).

I have not had any problems with the aluminum wire that I have used to hook up industrial machinery including a 30 HP air compressor and a 60 KW plastics machine that was nearly continuous duty when running, not duty cycle like with injection molding machines.

I also know someone who owns a house in Pepper Pike, Ohio that is about 1/2 mile east of Interstate 271. The catalytic converters out on I-271 are chewing up the COPPER wiring that is inside of his house. This is even though all of the new wiring is #12 minimum by law. It does not help that a previous homeowner hooked up #14 copper wiring to 20 amp circuits and messed up a few other things.

I consider #12 copper wire to be the minimum wire size for duplex 120 volt receptacles because the existence 0f 1500 watt comfort heaters and the widespread use of them makes 15 amp circuits illegal for any general purpose receptacle.

Mike Cole mc5w at earthlink dot net

Though it is true that energy loss in an aluminium conductor can be made equal to that of copper,eletrical components with aluminium conductors in a product can result in less energy efficiency by being bulkier leading to more friction losses etc.,

I use AL wire for Services ONLY, I would Never use AL wire in a building or house. If you use Al wire as per NEC You can save money on BID jobs. Train your men to install it right and you will be OK. Try it you will like it.

Aluminium is a good wiring method as long as it is installed properly. That is the problem if it is not it can be recipe for disaster.

Over the years I have investigated many fires where not aluminium wire was the cause, but how it was installed.

There are devices such as receptacles approved for AL, but many times the home owner will replace it with one bought at k-mart which is not approved for AL. Since the expansion rate of Al is greater than CU the wire will become loose on the receptacle terminal and start to heat,this can cause a fire.

Another issue if you nick one of the conductors while putting them in the ground it is usually just a matter of time before it will need to be replaced. If it happens to be in your service lateral and you lose one phase which creates a low voltage back fed, motors beware, you could lose your freezer and frig.

Al is a good alternative and will save money, especially with the price now of copper, but it requires a more secure method of installation.

Jim Yancey-NCDOI Engineering Consultant

Are Aluminum conductors required to be re-torqued at greater intervals than CU due to the increased thermal expansion? What about AL buss in equipment?

From Eaton's perspective as an electrical equipment manufacturer, They have to build everything to the UL standard. So I dont see a down side to using AL bussed equipment in lieu of CU bussed unless the maintenance required is greater.

If there is no additional maintenance required, and the physical size of the equipment doesn't change due to the larger pieces of AL, I dont see a down side.

Those of us who use both know that both conductors work just fine when used properly. I have had no problems with aluminum stranded conductors and I have read that today\\\'s chemical composite of aluminum conductors is not the same as that of yesteryear so the problem of surface oxidation is allegedly less. I prefer copper simply because it is faster and easier to install since it is smaller for the same ampacity--though one has to get a loan to buy it. The problem I have had with single-conductor aluminum is that it can not be bent or moved around inside a small outlet box like copper. In working with the old aluminum single conductor, two twists back and forth and it would snap. Another problem was in bending--it was and is very easy to bend a single-conductor aluminum into a super sharp curve (even back onto itself) which could overheat the conductor at the bend--if not just snap it. As far as splicing, I and others have been splicing the two together via cut-up bus bars every since it first came out. Now, the industry is catching up to us in that these cut-up bus bars are now (allegedly listed for such) being sold at the retail level for single-strand aluminum to single-strand copper splicing. Ironically, this is not really new. Burndy rectangular connectors listed for copper and aluminum splicing (14 gauge to 6 gauge) have been out for many, many years as well as mini split-bolt connectors (Madison ASB-10) that are rated for aluminum to copper (#16-10). Thus I have no problems with either copper or aluminum.

As far as using aluminum wiring within any facility I would be hard pressed to use anything smaller than 1/0, primarily due to space and bending restrictions. For the larger conductors, care still is the keyword in installation. Manufacturers now have many options for terminations. I have found one made by CYTO Meridian (Gulf Connectors, Inc; Lehigh Acres, FL) called "Cytolok". They are the best connection for aluminum or copper I have ever seen.

From a manufacturer's standpoint, AL is always going to be better than CU. No guessing where the copper association regarding CU stands on this same topic.

I would like to have seen an article with input from building owners discussing both pros and cons whom really does not have a vested interested in Al or CU because at the end of the day, they are the one who need maintain the electrical system, without waking up in cold sweat in the middle of the night.

Mike P

I am concerned over the sudden push for aluminum wiring, in many different forums.

The aluminum industry lost its' credibility in the late 70's ... when reams of "proof" were not consistent with field experience.

This latest marketing effort, by Eaton, deliberately muddies the waters. For example, they seem to say, at the end of the piece, that UL has decided aluminum wire is just fine. UL has done no such thing; they simply evaluate aluminum wire to standards that apply to all wire. They do not make any sort of judgment as to the performance of the product.

The paper starts with the misrepresentations by stating that both aluminum and copper are subject to oxidation. Sure, copper oxidizes ... but this ignores the fact that copper oxide is a decent conductor, while aluminum oxide is a poor one. (In line with this new sales pitch, an industry rep recently spoke at our IAEI meeting. The rep claimed NO need to use noalox on connections - or no more need than for copper).

One physical property also 'overlooked' in these sales pitches is the great malleability of copper. That is, your ability to twist, bend, straighten copper multiple times without failure. Aluminum is pretty much a 'bend once' material. This is a critical matter with "wire nut" sided wire gauges.

The aluminum folks claim no plans to re-introduce wires smaller than #6. Yet, I see very little room for the business to expand without making these branch circuit conductors; there just isn't that much wire used for feeding sub-panels, ranges, and dryers.

How do aluminum conductors compare to copper conductors in pulling operations in conduit where bend radius, run length and other factors were determined using copper as the model? How do aluminum conductors compare to copper in machine tool applications involving vibration? Correct me if I am wrong, But I seem to remember that a reason given for the use of aluminum here, in the 70's, was that copper was being diverted to the "electrification" of China. I also remember the closing of copper mines here at a later date due to "The economic climate". Is aluminum a suitable alternative, or is this politics?

I'd like to see something on steel for wire, especially in flex applications such as on milling machines and moving hoists. Steel can be "springier" if that's a word. It does conduct electricity. It's also stronger than copper and aluminum.

I have to work with moving machinery and hence moving wiring harnesses, and I have asked the makers of "continuous flex and continuous torsion" cable on many occasions to give me better stuff, and suggested steel to them.

We had a mix of steel and copper in our wire in the Army. When splicing, we would brush the exposed wire. The copper strands would stay bent and the steel would spring back straight. As I recall, we tied the stronger steel strands together in a knot, then wrapped this knot with the copper strands, and covered the whole thing with tape. This was commo wire, not HV.

If you find anything on using steel for wire, I'd be interested. Unless I'm missing some non-starter issue, I think that at least the flexible cabling industry is missing out.

Too many problems with Aluminium...... Aluminium is like the National Code... Bare Minimun ! Do they use Aluminium in Cuba ?

I agree with the study about aluminum conductors being a better conductor pound for pound and for medium voltage applications I wouldn't hesitate using it. However, I have seen too many aluminum connection failures on systems 600VAC and below to allow or specify aluminum conductors on any project. I am assuming conductor failure is a direct result of improper training on how to terminate aluminim conductors.

I have observed whole building electrical feeder systems fail becuase of improper terminations or wiring methods when aluminum conductor is used. A client Brought me into one of his buildings becuase some equipment was unusually hot. Unusually hot was not the right word as the equipment glowed in the dark, literally. Every panel, gutter or electrical equipment with aluminum conductors were failing and the ends weer crystalizing, a problem not as apparent with copper when it over heats. Had I specified aluminum feeders on this project I would have been looking at a major law suite. There has been other cases perhaps not as bad.

I'm presently working with a strip mall client that allowed aluminum service entrance conductors to serve a meter center and every splice in the gutter is failing. The strip mall will need to shut down the building to fix the problem, if the aluminum conductors are salvagable.

Personally, I don't want to deal with the potential of a problem unless I know who is making the splices and the terminations.

The history of aluminium wiring casted a shadow on its use. I have been opposed to the use of aluminium for those reasons. WIth the high cost of cooper, aluminium is getting to be more attractive to use. Compact aluminium conductors seems to be more common these days. By using compact aluminium provides a more robust cross section when terminating them. With less void between the stands means that is it harded to "smoosh" them They still require TLC and proper torquing to ensure a good, solid connection. Another nice thing with compact aluminium is that the conductors OS diameter is usually smaller then copper. For example, a 3/0 xhhw OS diameter is .72" while a 4/0 compact aluminim is only about .59 This means you should not need to increase the conduit size to allow the use of larger aluminum conductor. I personally will still limit its use but will be warm to the use of aluminium. If you are thinking to use aluminium, do your home work like local codes, be certain that your connectors are "AL" rated, and torque properly.

Mike, I do not know if you read Electrical Contractor and Maintenance Magazine (EC&M) but they had a very good article on aluminium conductors in their January 07 issue.

In rsponse to the article al is so much better that cu.

It must be upsized to have the same amperage as cu.

The radius bending is greater.

I don't know of any recpt's and or switches that are approved for al.

If you will check your history, there have been more electrical fires caused by al than any other electrical component properly or improperly installed.

I for one, think that al wiring should be outlawed. We need to think of safety and quality instead of making that extra dollar profit.

Jerry

Great paper! One point that I did not see in this article is mix use of Copper (CU) and Aluminum (AL) and the electrolysis effects.

Keep up the great work,

Jerry 516-524-9440