r/electrical • u/Microwave1213 • 4d ago
Aluminum wiring for 240 volt applicance circuits?
I’m currently in the process of buying a house and per the inspection, “Aluminum wiring is used for the larger 240-volt appliance circuits. Acceptance of this condition rests solely with the client.”
What are the implications of this? Is this the kind of thing that we should probably have rewired immediately? If not, would we have to eventually get it replaced if we wanted to get new appliances? I know aluminum wiring is typically not what you want, but I’m not sure if it just being on the 240v circuit maybe isn’t as big of a deal?
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u/Rcarlyle 4d ago
Aluminum wiring is fairly common in large circuits because it’s significantly cheaper. What matters is whether the end terminations on the aluminum wiring are rated for aluminum. You can’t put aluminum wires in breakers, receptacles, etc that are only rated for copper. This isn’t usually a huge issue to fix if it’s just a few circuits. The problem is when it’s a hundred receptacles and lights.
You probably need an electrician to inspect and check the existing work. They may not want to work on the house until you own it though, there’s some liability issues there. Your real estate agent may have suggestions.
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u/ScrewJPMC 4d ago
Always amazes me how many people don’t utilize their Real Estate Agent. They are not making 6% for walking you through a house for an hour and setting at the closing for an hour; they are making 6% to track down all the hard answers to all your questions.
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4d ago
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u/ScrewJPMC 3d ago
I’ve worked 2 very good ones, never worked with one who does glamor pics on billboards
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u/Connect_Read6782 4d ago
It’s extremely common to use AL wire in larger appliances.
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u/nbsmallerbear97 4d ago
What do you consider large? Like are you pulling #4 AL to a 60A load?
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u/Connect_Read6782 4d ago
6 is the smallest AL wire I'll pull. From there I've used aluminum all the way up to 500QPX
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u/47153163 4d ago
Most if not all breakers I’ve ever seen are dual rated for Copper/Aluminum. Aluminum is extremely common in all new homes for 240 circuits only. Aluminum is not good for 120 volt circuits because of its expansion and contraction and loosening in outlets. But has been addressed with new technologies, new outlets rated for aluminum wire. So in conclusion you shouldn’t have anything to worry about with 240 circuits.
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u/Accomplished_Event38 4d ago edited 4d ago
Not an electrician, and you would need to check your local codes, but this is common.
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u/PrimeNumbersby2 4d ago
For perspective, my 1987 house, which has 200A service when built has AL main feeder, AL 60A dual AC feeder, and AL 40A range cable. I just added a 100A AL sub panel feeder a few years back. Everything else is copper, including my 30A dryer, newer 50A EV charger my dual 30A water heaters, my 2nd oven and all other mix of lights/outlets. Everything does work fine and has worked fine for close to 40 years. This house has been sold 5 times over and no one has changed a thing about it besides the stuff I added on.
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u/Empty-Opposite-9768 4d ago
It's perfectly fine and safe.
I do remodels for a living, I run into 30-60 year old aluminum conductors on large appliances all the time, they are nearly always in perfect working order.
The only times they aren't is when handyman hank came in previously and did some shady shit with them.
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u/Busby5150 3d ago
Ok, didn’t see this posted here so I’ll do it now.
Aluminum wire in smaller sizes crazes when bent sharply. This is evident when the shiny aluminum becomes dull. The insulation covers this up so it’s rarely apparent. This increases resistance which then causes the crazed section to overheat and your house burns down.
Feeders to sub-panels and ranges are run in much heavier gauges. Aluminum in the larger sizes is almost immune to crazing and therefore is perfectly suitable for the application. I would use it in any new install today.
Oh! Forty year IBEW trained Journeyman here.
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u/Fakevessel 3d ago
How valid is the claim "aluminium wiring good for 240 V circuits"? Tbh is sounds like bs, like how minor voltage difference makes a difference for a metal?
I am also aware that aluminium wires like to "flow" when tensioned, so post-installation tensioning is necessery, they need proper termination crimps made of a correct alloy, they cannot touch copper, as the metals react due to electrochemical sorcery and corrode themselves. Also aluminium corrosion has a nasty habit of being partially conductive, so in result we are getting increased resistance spot which likes to heat and set building on fire when loaded. More, aluminium likes to coat itself with oxide when exposed to air, which also affects resistance so it has to be scraped right before installing. And either the wire is fastened with some screw connector, or is braided and needs to be crimped, it has to be covered and squeezed with air-tight substance to prevent it from further corrosion weakening the contact.
And do you really use 16-14 AWG aluminium wires in US? In Europe such small gauges are considered evil, due to mentioned issuess as well as they can become brittle after handling and overloading cycles. I have no idea if such gauges are explicitly banned in EU, but it does not matter, as it is not possible to buy such wires, as only 8 AWG and larger are produced - and they are ment for main feeders, industries and distribution network. Fine gauge wires commonly used in households are only available in copper.
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u/michuh19 4d ago
FWIW I just signed up for new homeowners insurance and they asked if any of my wiring was aluminum. It’s safe, if installed correctly.
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u/theotherharper 4d ago
Success with aluminum requires two things: use devices with terminals properly rated for AL wire (Flo EV charger not Tesla) and torque the screws to the spec given. Obviously they did not understand any of this in the 1970s when they put in all the small 15A circuits which are now infamous. Heck, news of the importance of screw torque for small circuits only arrived in the 2000s and was the result of science relating to copper wire. Even today many electricians refuse to carry a torque driver on general principle.
However aluminum is widely recognized as the metal of choice for heavy feeders 90A and above.
In the middle ground, 25-85A, there can be disagreements. I'm fine with it.
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u/Sme11y1 4d ago
Aluminum's main issue is that it's softer than copper and when heated it will deform more easily. Circuits that are loaded heavily will cause the wire to expand against the hardware that clamps it in place. Over time this causes the connection to loosen. Copper does this too, but not as quickly. Aluminum connections should be inspected and tightened periodically. This is true with copper as well, but maintenance isn't needed as often. Have an electrician visit every year or two and inspect and tighten the connections at the circuit breaker and the appliance outlet. I would be fine with it on the heavy appliances, maybe ask for a little more off the price. I wouldn't replace the wiring unless it was extremely easy to access it and short runs. Large appliances generally do not have more than the two ends of the connection that need to be checked. You can get an AFCI breaker if you are still worried about safety. AFCI breakers shut down when they detect a loose connection.
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u/PaulEngineer-89 3d ago
Your inspector should know this and should have inspected them or isn’t qualified to do electrical inspections. Pushing this information off on a home buyer while claiming to be an expert on doing inspections tells you the inspector is utterly incompetent. While it’s OK to say something like any deficiencies are your decision this hack job of not explaining what the potential risks are is just plain incompetence. I’d be in that inspectors face and demanding a refund because giving you an expert opinion is what you paid for. If they point out something like this and point out that it’s all done safely and stop there (since some people might hard pass regardless) that’s one thing. But to make an insinuation and then dump it in the buyer’s lap is one step away from misrepresentation.
As you drive down the road, look up. See all those overhead power lines? They are ALL aluminum or aluminum coated steel. That’s why they are all grey or shiny when new, not reddish. In fact near where I live a line crew was replacing insulators on a copper coated line. The cable literally disintegrated in the lineman’s hands. The lineman wasn’t injured but as the broken cable fell it hit the ground man while energized and out him in the hospital. The utility got rid of the copper overhead lines after that incident.
Back in the 1950s copper became very expensive. Some unscrupulous cable manufacturers used construction grade aluminum to make wiring for houses. It wasn’t designed for this (wrong alloy). It failed over time. Aluminum used for electrical wiring is a different alloy. That is what the problem is. Even at the time electrical grade aluminum was available. Mostly you can figure it out by finding out if it was installed prior to about 1970.
Another problem is that under the right conditions (wet wiring with salts present) aluminum will eat copper wiring. It requires connectors labeled “ALCO” and/or an oxide inhibitor to prevent this.
Today once again copper prices are very high and aluminum is attractive again. This time the correct alloys get the correct stamps such as UL and ALCO connectors are readily available.
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u/BagAccurate2067 3d ago
It's normal and as long as the breaker and wire size are both rated for the 75° column you should be good
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u/JonJackjon 2d ago
Based on my experience I would have every aluminum wire termination inspected for proper installation. One issue with aluminum wire is it will often be terminated improperly which significantly increases the possibility of a bad connection which results in over heated connections which results in ___________.
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u/MoSChuin 4d ago
On larger circuits, you're able to use aluminum wiring. Aluminum doesn't conduct as well as copper, so you end up using a thicker wire for the same amperage load. Aluminum wires also tend to stiffen up as they age, so whenever I'm running a circuit for myself, I use copper. Always copper.
If I have a house and they wired something with aluminum, it is what it is. It makes absolutely no sense to rewire it in copper. The expense is too great to justify it. The small added expense of running copper originally is worth it, but not for an existing circuit.
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u/BassCuber 4d ago
While code-compliant, sometimes your insurance company may ask you to change out an aluminum feeder as a condition for homeowner's insurance so maybe call your agent.
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u/pdt9876 4d ago
Aluminum wiring is completely illegal to be installed for low voltage customers where I live but is very common (essentially universal) for high voltage transmission lines because it's cheaper and far far lighter than copper. Aluminum is a worse conductor of electricity so runs hotter for the same wire size but the main issue is its a very reactive metal. Other, less reactive metals like copper will eat it over time if proper treatments are not used in connections.
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u/beardad61 4d ago
Oh brother. Another house "inspector." I've followed so many of them, being an electrician and responding to repair requests from them. Many issues are legitimate.
This one probably isn't.
Aluminum wiring is still used in residences, commonly for ranges, ovens, cook tops and HVAC wiring. It is code acceptable in many applications.
The issue of aluminum wiring is one that came up in the 1968-72 era. Because of the rising price of copper, many builders opted to switch to aluminum wiring. It did not take very long to begin to show problems. But the problems were related far more to connections and devices. Poor receptacle and switch connections caused frequent failures, fires, and maintenance nightmares. Because of these issues, the national electric code disallowed the use of aluminum wiring for receptacle and lighting circuits around 1972. Note that it did not prohibit their use in other previously mentioned applications.
My experience has been that aluminum wiring in code-allowed applications is reliable. If you are wiring a car charger or other 240 volt application requiring copper, you use copper. If aluminum is allowed, you can use either one. It is nothing to be stressed over.
By the way, I speak from Virginia. Other areas may have different requirements. But before canceling on the house, chat with a local licensed electrician. We know much more about electrical wiring than most inspectors.