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My home has aluminum wiring, which was wired approximately 20 years ago. A single line of wiring connecting bathroom geyser caught fire and got burnt. I am planning to rewire my house again.

Should I be getting my entire home rewired with copper wiring or only the part which got burnt? Apart from high cost of copper wiring what other advantage I would be getting?

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    Keep in mind that Aluminum wires by themselves are not dangerous. The problem is the formation of oxidation on the connections coupled with the use of non-Al rated connectors and improper methods. Done properly, Al wiring is as safe as Cu. That being said, some localities have banned its use. Check with your local zoning authority for their rules. – jwh20 Jun 18 at 11:00
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    Also, since you had one connection fail, it's quite possible that many others if not all others are at risk as well. You should inspect ALL of your switches, outlets, and any connection boxes for improperly joined Al wires or non-Al rated devices. – jwh20 Jun 18 at 11:27
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    Where are you on this planet? Are AlxCu rated miniature splicing connectors (Alumiconn, MAC-Block) available where you're at? – ThreePhaseEel Jun 18 at 11:40
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This doesn't sound like a technical question. You didn't maintain the AL wiring properly... it had a problem... should you replace it? The real question is do you trust yourself to maintain it going forward?

Same exact thing probably would've happened with copper.

I do systems rollouts within enterprises, where you get employees to switch to a new business system. People don't like change. New systems don't fit old ways. It was much worse in the 60s-70s when the first automation was happening and many failed, for many reasons. In most cases using Sperry vs Burroughs vs IBM made no difference - employees were uncooperative, management didn't listen, etc. If a company bought IBM, then management presumed the computer was OK and confronted their internal problems. But if they bought Burroughs, they'd take the easy out of blaming Burroughs. So if you were responsible for picking vendor, you picked IBM.

That's called a "Halo Effect".

Same with copper wiring. The same exact problem happens in 2 different junction boxes. If it's copper wire, "it was a mistorqued screw". But if it's aluminum, "OMG it's the aluminum wire" and that's as far as people's brains go.

So that's most likely what happened there, if it was copper, it still would've failed owing to faulty workmanship, and it wouldn't even occur to you to rewire your whole house because if it lol. And by the way, the wire didn't burn up, the wire termination (end) did.

In reality, it's copper lugs. They do not play well with aluminum wire. Aluminum lugs work well with both, which is why they are widely used: Tear apart an Alumiconn; it's made of aluminum. Ditto a Mac Block, ground bar, and many panel lugs.

But aluminum wire is not better than copper; you can still screw it up in all the usual ways. We just have to add "failing to use Al-rated terminations" to the mix.

My Rx for aluminum wire

First, you fit arc-fault protection (usually at the circuit breaker). That will catch many/most of the kinds of failure we worry about with Al wire.

Then, you visit every connection point and make sure it has terminations rated for Al wire. That means (in the US) CO-ALR receps, Alumiconns, MAC Blocks connectors etc. (and I dislike purple wire nuts because it's not that simple; you do need to physically separate Al and Cu wires, and there are lots of pix of melted and charred purple wire nuts.) And in cases where you must attach to equipment not available with CO-ALR termination, you pigtail to copper for the last 6 inches.

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    My key takeaway (since we're bringing business into play): One bad joint doesn't mean throw everything out, but assume that there may be other bad joints. It's much cheaper to inspect and repair the whole wiring system than it is to replace the whole wiring system. Once you've inspected and made sure everything is up to snuff for aluminum wiring, it will be just as safe and have just as few problems as if you rewired the whole thing with copper. – FreeMan Jun 18 at 15:25
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Labor will be the bulk of the cost

Wire itself isn't that expensive. It might look pricey in the stores, but the shorter the cut, the higher the cost per foot. A local big box sells 15' of 12/2 for $11 (about $0.73/ft), while a 1000' spool is $233, or $0.23/ft.

Pulling the old wires out and fishing new ones in existing walls is time consuming and electricians don't work cheap. Remember, the wires are probably stapled inside the walls, which can complicate removal. If you ever decide to gut a room, take the opportunity to remove the ALR wires and replace them with copper. Even if you don't do it yourself, it's cheaper inside open walls.

Should I replace all the wire?

While that is the safest route, consider the next step down. I bought a house with ALR wiring and it still mostly has that wire. The main thing to consider is that ALR takes more effort, since you can't just use a copper device. I've found that if you take the time to make sure you're using CO/ALR, or you splice copper in appropriately, you have very little fire risk.

The catch is you're going to have people treat the wires incorrectly. I had to have a tankless water heater installed in the attic. It has an electric ignition so it needs an outlet. Rather than fight the plumber later if things went badly, I had him have one installed by an electrician he works with. The guy put a purple antioxidant nut on it (I wound up moving it onto an all-copper circuit I added later). Remember, the bulk of your fire risk is not from corrosion, but copper and ALR twisted together, heating up and then arcing.

This is why AFCI breakers (many of which are rated for aluminum) can give you enough security without a rewire. It's pricey, but if you have some connection fail, you won't have an electrical fire. That and insisting on proper splices when you need to join copper to aluminum.

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If you can afford it you should rewire the entire home. Without knowing the exact circumstances that caused your recent fire, it might be safe to assume it could happen again. Aluminum wiring in itself isn’t bad. It is the junction between it and the wiring devices that are the issue. Most older devices were made for copper only, and the junction of dissimilar metals cause issues. Aluminum conductors are only used now for large feeders in commercial and industrial applications. Residential wiring must all be copper for new construction. Consult with a licensed electrician in your area for further advice.

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    Some jurisdictions still have a hangover from the days of AA-1350 NM, but in general, the NEC does not prohibit modern aluminum wiring (AA-8000 series alloy aluminum) from being used in just about any occupancy, nor does the CEC have a blanket prohibition on the use of aluminum wire, either... – ThreePhaseEel Jun 19 at 1:13
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copper wiring is considered to be the best wiring for home or residential purpose, it is more stable than aluminium wiring. Though aluminium wiring is lighter and cheaper than copper wiring is more beneficial for long distance wiring and not residential purpose, being a small conductor its need to transmit more power load. Hence Copper wiring is more durable and secure than aluminium wiring. In my suggestion go ahead with rewiring the entire house as it is said precaution is better than cure.

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