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thinksincode 07-05-2013 03:42 PM

Question on home inspection & aluminum wiring
Hi all,

I'm looking at my home inspection report back from when I bought the house and am confused about some notation about aluminum wiring. From everything I've read, it seems it's really bad to have aluminum wiring in the house.

On the Electrical page of my home inspection report, this is what I see:

If yes, are tips coated with anti-corrosion inhibitor.... yes
If yes, is breaker rated for aluminum wire.... yes


It then has a section about VISIBLE CIRCUIT WIRES, where "alum" is circled for Services Wires and Feeder Wires, then "copper" and "alum" is circled for Branch Circuit Wires.

What is the difference between stranded aluminum wires and solid wires? Does this mean something is unsafe with my electrical system?

Daniel Holzman 07-05-2013 03:57 PM

A solid wire is made up of a single strand. The gage of a wire refers to the diameter of the wire. A #12 wire, for example, has a diameter of .0808 inches if it is solid (single strand). A #12 stranded wire has a diameter slightly different than a solid wire, see for example for the diameter of a wide variety of different types of stranded wire.

Stranded wire is typically used because the wire is far more flexible than solid wire, which makes it much easier to work with, especially in large sizes. Stranded wire may require different types of connectors than solid wire, which is why your inspector noted that the breaker was rated for use with aluminum wire.

Aluminum wire is prone to oxidation (corrosion) when in contact with non-aluminum connectors. This is why your inspector noted that the aluminum wire was coated with an anticorrosion inhibitor. Aluminum also has a different coefficient of expansion than copper, which is why special connections are required. Connections designed for aluminum wire are designed to maintain proper tension even as the aluminum expands and contracts due to heating and cooling under load.

Aluminum wire got a bad reputation during the 1970's I believe, when copper prices went up significantly, and some contractors started using aluminum wiring for branch circuits, and failed to use properly rated receptacles and connectors.

There is absolutely nothing wrong with aluminum wiring if it is properly installed, using UL approved connections. In fact, there is a very high probability that the wire feeding your house is aluminum, since aluminum is less expensive than copper, and is less dense than copper, it is extensively used by power companies for medium and high voltage lines.

I don't see anything in the inspector's report that indicates an unsafe condition.

TarheelTerp 07-05-2013 04:11 PM

^I think Dan gets paid by the word.

The only problem with aluminum wire is the solid stuff used in some homes
during a copper market crisis (late 60's - early 70's). You're fine.

thinksincode 07-05-2013 04:28 PM

My house was built in 1968, but I think they upgraded from 100 to 200 amps about a decade ago.

I was concerned with the aluminum because I was reading something about insurance companies dropping people when they found out there was aluminum

If I understand correctly, the solid aluminum wires were used in branch circuits. But according to this report, he said he observed no solid aluminum wires, then under "branch circuits" circled both copper and aluminum. I was just confused.

Jim Port 07-05-2013 04:57 PM

The report does contradict itself.

mpoulton 07-05-2013 06:03 PM

My assumption from the report is that there are no "bad" aluminum wires - small solid conductors for branch circuits. There are "good" aluminum wires - larger stranded conductors for service feeders and large branch circuits. I assume the aluminum branch circuit conductors he noted were for high current devices like air conditioning or an electric range.

creeper 07-05-2013 06:46 PM

In my province an insurance company will not sign off on an insurance condition for a resale home, unless each and every receptacle has been inspected by TSSA certified inspector.

The public is definitely divided on the safety of aluminium wiring. Both sides strongly advocating for their own beliefs.

I have heard master electricians and fire officials both say their kids would not spend a night in a home with it.

clashley 07-05-2013 07:01 PM

The issue is not with the aluminum material itself, but if the wiring was installed correctly and used with appropriate devices and connectors. I wouldn't worry about aluminum wiring supplying direct-wired appliances like an HVAC, or as feeders for panels/subs, but it would make me nervous to have it on branch circuits. Even if the wiring was correctly installed to begin with, it's difficult to know what an unsuspecting homeowner or contractor might have done to the system in the intervening years.

If I were the OP, I'd take a look at the inside of the panel and see what wiring is used on the branch circuits. If I found a aluminum, I'd be calling a sparky to give the system a throrough checkout... if I found copper (without any obvious signs of problems), I'd close 'er back up and call it a day.

Speedy Petey 07-05-2013 07:40 PM


Originally Posted by creeper (Post 1212059)

The public is definitely divided on the safety of aluminium wiring. Both sides strongly advocating for their own beliefs.

I have heard master electricians and fire officials both say their kids would not spend a night in a home with it.

Problem is you CANNOT just say "aluminum wiring". That is too broad.

Older AL branch circuits wired with solid #12 & #10AL NM cable were a problem.
Larger cables in services, feeders and branch circuits wired with SE and/or SER cable were NEVER a problem, and are still not a problem to this day. In fact, today's AL SE and SER cable is MUCH better than it was 20 years ago.

That inspector's report shown above is one of the best I have ever seen. It actually acknowledges this.

creeper 07-05-2013 07:47 PM

Larger cables as in commercial applications??

I am not an electrician so I cannot engage much further in this discussion. I really don't have an opinion, I just know as a Realtor I have been caught in the middle of opposing arguments for and against.

I only offered my view because I thought the op has a right to know that many electricians are in fact against it.

Speedy Petey 07-05-2013 08:19 PM


Originally Posted by creeper (Post 1212089)
Larger cables as in commercial applications??

No. I'm not sure how you equate larger cables with only commercial. :huh: The topic is home inspections.

Larger as in #6 or 8 and bigger.
Services typically use #2, 1/0, 4/0, 250mcm.

oleguy74 07-05-2013 08:33 PM

I have a lot of houses wired with al wire.none of which has stranded wire for branch ckts.all solid.stranded al that is.water heaters were wired with #10 al and some with #10 copper.for the most part,al is fine if switches and recp's are used for al or copper.main feeders are the only stranded used here.some may not know but #12 alu is only good for 15 amp and #10 is for 20 amp on branch ckts.

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