aluminum wiring

Observed aluminum wiring in a sub panel of a 16 year old house today. This is the first time I have seen solid strand in a newer house like this and I recommended review of connections and application of anti oxidant paste to terminals by a qualified electrician familiar with aluminum wiring. Looking for advice before I send report out.




Aluminum branch wiring is a red flag. It needs to be deferred to a licensed Electrician.


This depends on the size and application of the conductor.

True, #12 & #10 solid used for general use branch circuits is bad, but larger conductors are fine and still used today in many applications.

Thanks David,

as you see from my post that is what I wrote up, but since I hadnt seen solid strand 10 awg in newer construction I wanted to make sure I am not aware of some type of alumicopptinium if you know what I mean. The sheathing stated some type of metal mixture that I have never seen before but dont recall what is was since I called it out for further review anyways.


I see copper right below that. How much was aluminum? I am not even sure where you would get 10ga al 16 years ago and it should be the new alloy if it was bought new then. The insulation looks like TW so that might just be one circuit put in with antique wire

If this is newer construction, that must be tinned copper.

Why would you recommend the use of this junk?

David, I think tinned copper is an older technology than aluminum.
In 1993 it would be hard to find either one of these in a supply house and niether would be in a home store.
It sure looks like pre 1986 aluminum to me (TW insulation). That is why I asked how many circuits are wired with it. This coukld be a homeowner addition using something he had saved along with his leisure suit and platform shoes.

That’s what I thought, it does indeed look like aluminum wire to me. But the build date screwed me up.

It looks like my aluminum wiring here…

Because that is what I was taught. Isnt it supposed to prevent contact with air which promotes oxidation, hence the ANTI oxidant paste. Do you have a reason to not recommend it? I am always open to learn , that is why I asked for opinions.


That sure looks like the old NM with the TW insulation to me which makes it pre-1986. Either that house is 20 years older than they say or they used some antique wire when they built it.
That has always been a question, does old technology lose it’s listing when newer technology comes along? Could you wire a new building with cloth covered wire and black painted conduit and boxes?

BTW were the devices CO/ALr? It should be stamped on the yoke where you can see it with the cover off.

110.14 Electrical Connections.
Materials such as solder, fluxes, inhibitors, and compounds, where employed, shall be suitable for the use and shall be of a type that will not adversely affect the conductors, installation, or equipment.

The reason I posted the code section was to show what the code said about the use of antioxidants.
If it is used then it must be suitable for the use and the only people that can say what is and is not shall be suitable for the use are the manufacturers of the terminal and conductor.
Therefore if the terminal or the conductor manufacturer does not include something requiring the use of an antioxidant there is no need for its use.

The only time I use the junk is when it is required be the manufacturer of the terminal and these are far and few between.

When an antioxidant is used there are several steps that must be followed in order for it to function properly. It is not as simple as squirting a little in the hole and then installing the conductor as most do when using the junk.

First the conductor must be cleaned with a wire brush. If it is a stranded conductor then the strands needs to be separated and each strand brushed and then reformed into its original shape. This bending and brushing of the strands often damages the strands and the end effect is worse than if no antioxidant was used.

On a side note; if I was worried about the conductor oxidizing and causing some sort of damage to anything then I would install a copper conductor.


Did you, or can you take a real close up picture of the information that is pasted on the cabinet, or on the inside cover? That information contains the instructions, and if the “Conductor Termination Compounds” is required, that will be the reason for recommending that it be used.


**Conductor termination compounds are for use on splice and termination connections of aluminum, copper-clad aluminum and copper conductors where used to retard oxidation at the conductor/connector interface. These compounds do not have a deleterious effect on the conductor metal, insulation or equipment when used in accordance with the manufacturer’s installation instructions. I also see the use of a white wire on the lower breaker, and that the wires you describe show signs of being “knicked”

I really hate getting in the “goo” fights because I really don’t have an opinion and I do use it (just to keep other inspectors happy) but I agree with Mike. It is not required and you are never really sure you have cleaned the wire enough to actually acccomplish anything.

When you read the lug manufacturer’s instructions they “recomend” using the goo, wire brushing the wire etc but it is not a requirement. Alcan (wire manufacturer) says it is not necessary and in their tests it had no effect if the lug is properly torqued (gas tight). The oxide layer is destroyed in the torquing process.
They are also the ones who point out an aluminum conductor in an aluminum lug (which most are) is a better chemical match than copper (but they don’t sell copper :wink: ).
As an inspector I would never fail a job because of a lack of goo.

Hmmmmm, very interesting Gentlemen.

Interesting information and images from the field

I would eliminate the red portion.

Illinois makes it pretty clear what they want us to do …

When, pursuant to the written agreement with a client, the electrical system is inspected, the home inspector shall:

  1.     Inspect the service drop, the service entrance conductors, cables, and raceways, the service equipment and main disconnects, the service grounding, the interior components of service panels and sub panels, the conductors, the over-current protection devices, installed lighting fixtures, switches, and receptacles, the ground fault circuit interrupters;
  2.     Describe the amperage and voltage rating of the service, the location of main disconnects and sub panels, the wiring methods; and
  3.     **Report on the presence of solid conductor aluminum branch circuit wiring** and on the absence of smoke detectors.


Upon review of your post I have been recommending too many repair recommendations and should just refer it to a qualified professional.

I need to fix this before it gets me in trouble every time a buyer asks me “so how do I correct this…” trying to help has gotten out of hand I guess.

Thanks everyone for your help.