Originally Posted By: kbliss This post was automatically imported from our archived forum.
Sometimes it is hard to identify what the service conductors are made of, copper, aluminum etc. just by looking at them. There is usually little or no visible cable exposed. How can I determine what they are? Do I do this by the size in correlation to the service?
Originally Posted By: jmcginnis This post was automatically imported from our archived forum.
Don’t go by size … some electricians like to oversize conductors just to be on the safe side… are you opening the panel covers? You can usually see some bare conductor at the main lugs… also if you see some “black or grey goop” on the termination it is usually aluminum… by the way … the goop is actually called “anti oxidant compound” …you can also read the intials “AL” or “CU” on the cable jacket if it is installed with the writing to the outside…
Originally Posted By: jmyers This post was automatically imported from our archived forum.
John,
I know many women you have met probably told you size does not matter but in this case it does. You certainly would want to check if the conductor was under sized. 
Originally Posted By: tpfleiderer This post was automatically imported from our archived forum.
Kurt,
If the service entrance conductors is copper or aluminum is not as important as the size of the conductor. Most of your new and upgraded services within the last 10 years + have been aluminum conductors because of the cost. It is OK to use aluminum conductors for a service entrance cable ( you can not use aluminum conductors for branch circuit conductors because of the fire hazard). Now, the material (copper or aluminum) does matter when looking at the size of wire being used for the amp load that is being drawn. Copper wire is usually called out in the code book as being able to carry a larger amp load per size then aluminum. If you pull the cover off the panel box you can usually tell the difference. With aluminum you will the anti-oxidant compound (a grey or yellowish paste) on the wires and with copper there is not any paste.
Originally Posted By: rray This post was automatically imported from our archived forum.
Timothy Pfleiderer wrote:
(you can not use aluminum conductors for branch circuit conductors because of the fire hazard)
Out here we can use aluminum conductors for branch circuits depending on the size of the circuit. Single-strand AL in 15A and 20A circuits apprently is the problem one. Single-strand AL in larger circuits and multi-strand AL apprently is okay from what I've read and from what our electricians here tell me.
Timothy Pfleiderer wrote:
If you pull the cover off the panel box you can usually tell the difference. With aluminum you will the anti-oxidant compound (a grey or yellowish paste) on the wires and with copper there is not any paste.
Key word there was "usually." I never see anti-oxidant compound on multi-strand AL.
Originally Posted By: jmyers This post was automatically imported from our archived forum.
Quote:
(you can not use aluminum conductors for branch circuit conductors because of the fire hazard)
I see aluminum wire all the time, like for heat pumps. They use SE cable to wire the emergency backup heat and to wire the unit itself. Is this wrong? Are they not allowed to do this? Please include the code reference with your answer, thanks.
Originally Posted By: gbeaumont This post was automatically imported from our archived forum.
Except as specifically limited in this section, the wiring methods and materials included in this Code shall be used in mobile homes. Aluminum conductors, aluminum alloy conductors, and aluminum core conductors such as copper-clad aluminum shall not be acceptable for use as branch-circuit wiring.
Originally Posted By: jmcginnis This post was automatically imported from our archived forum.
Ok… I will weigh in on this even though I don’t have my code book here to give you the reference but this might help… you can use aluminum conductors if they are stranded… stranding starts at #8 AWG… you cannot therefore use #10, 12 or 14 for branch circuit wiring… this is in accordance with the standards of the NEC… there are certain townships and cities, etc…that will not allow you to use aluminum anywhere even at the service… and the NEC does require you to use anti-oxidant compound with all aluminum terminations… you may not always be able to see the compound because manufacturers instructions tell you to wire brush the conductor, apply the compound and wipe off the excess… inspite of these instructions, most electricians like to use alot of compound and leave it on so the electrical inspector can notice it…of course, it is possible some electricians don’t use the compound at all but this should be called out by the electrical inspector at the time of installation… I will check on a reference for all this tomorrow …
Originally Posted By: rray This post was automatically imported from our archived forum.
John L. McGinnis wrote:
you cannot therefore use #10, 12 or 14 for branch circuit wiring... this is in accordance with the standards of the NEC...
I was really bored this morning, so I was reading the NEC.
310.14 Aluminum Conductor Material. Solid aluminum conductors 8, 10, and 12 AWG shall be made of an AA-8000 series electrical grade aluminum alloy conductor material. Stranded aluminum conductors 8 AWG through 1000 kcmil marked as Type RHH, RHW, XHHW, THW, THHW, THWN, THNN, service-entrance Type SE Style U and SE Style R shall be made of an AA-8000 series electrical grade aluminum alloy conductor material.
Anyone care to translate?
It looks like single-strand aluminum is okay at 8, 10, and 12 AWG in branch circuit wiring. I'm not that bored, so I'm not reading any further or I'll read myself to sleep.
Whomever created the index for my copy of the NEC sure doesn't understand the purpose of an index.
It was an interesting article, but it didn't go into detail about aluminum branch wiring. We still have the issue about is it allowed, what sizes are allowed, single-strand or multi-strand?
And I sure don't like the very last two sentences:
Quote
A qualified Home Inspector
will be able to evaluate your homes Electrical System.
If problems are found he will be able to tell you
the proper course of action to ensure
repairs are made properly
Unquote
I'm not going to evaluate anyone's electrical system in this state. And I am not going to tell anyone the "proper course of action to ensure repairs are made properly." I'm going to recommend a qualified electrician to do that; that's what they get paid for.
Originally Posted By: jmyers This post was automatically imported from our archived forum.
Russel,
I am pretty sure what you are reading is the composition of the aluminum. Recently they changed the compostion of the aluminum to make it safer for wiring. When electricians come across aluminum wiring connectors now have to be made of the new composition aluminum and since they changed the composition they don't have to use the anti oxidant any longer on those connections.
The article that was posted by Dave is simply showing that the aluminum wiring is not the cause of the fires but the connections to the wire. The NFPA has changed the ratings on those connectors so they now have to made with the newer composition aluminum and again they don't have to use the anti oxidant any more with those connectors.
My biggest question on this one was, if you are inspecting this stuff how can you tell the difference between the older connectors and the new connectors made with the newer compostion aluminum? The answer was, there is no way to tell. If you see no anti oxidant you can assume they are the new connectors. This is not really a good idea in my book because most electricians around here did not use anti oxidant on the old connectors, most don't even put it on the SE cables at the meter base or the main breaker.
My solution...get rid of it! 
Originally Posted By: dvalley This post was automatically imported from our archived forum.
I always tell my client to have anti-oxidant put on all aluminum stranded wiring when I can not see it. Usually something else has to be done that requires an electrician, so I just add this to the list.
I’ve seen new construction here in Massachusetts where they are still using anti-ox on aluminum entry.
How do we know when anti-oxidant is not required or when the composition of the wiring does not require it?
Originally Posted By: roconnor This post was automatically imported from our archived forum.
Russel is correct that AL wire is permitted in new construction (unless there is a local restriction) down to AWG #12 for 15A circuits (Both IRC and NEC), although that is not common in my area.
The newer AA-8000 series AL wire is much better and doesn't have the same problems as the old style AL wire. But for a given circuit, aluminum wire still has to be larger than if it was copper. Also, the newer AL wire usually doesn't require the oxide inhibitor compound (see links below) as long as the connector is listed for AL, CU/AL, or CO/ARL (no marking means CU only).
The real hazard is older AL wire AWG #10 or smaller (which is solid, as #8 and larger must be stranded) in homes build in the early 1960's to 1970's with what is called "old technology" aluminum wire. Even AL wire up to a few code cycles ago had some issues, including AA-13000 series AL wire.
I would red flag any AL wire AWG #10 or smaller in any existing home that does not have the CU pigtails and special AMP compression type crimp connectors (no wire nuts). Even with the correct pigtails and AMP connectors, some home insurance companies may not insure a house with old AL wire, so be careful. 
The following links have all you ever wanted to know about aluminum wiring but were afraid to ask ... lol ... including links that talk about terminating AL wire and CPSC #516 on old AL wire and proper pigtails. The first page of CPSC #516 also has a good section on warning signs to look for:
Does everyone call this out when it is not seen?