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Thread: Aluminum wiring

  1. #11
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    Quote Originally Posted by MNSparky View Post
    I'll see the AL NM maybe once every couple weeks here. What's really rare are the houses wire in flex with AL THWN. I've only seen 3 or 4 houses like that. We completely re-wired one with CU in 3 days with no rock cutting.
    Sounds like someone ventured up from Chicago to wire that one.

  2. #12
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    Quote Originally Posted by GeorgeB View Post
    BUT ... with aluminum 12 AWG was for 15 amp circuits, 10 AWG for 20 amp circuits. If he has 12 on a 20, change the fuse or breaker.
    Good catch. I missed that the aluminum wire is undersized for the OCPD rating.
    Bob

  3. #13
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    Oct 2009
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    Quote Originally Posted by bluecollar84 View Post
    I thought aluminum house wiring was unsafe?


    Sent from my iPhone using Tapatalk
    Aluminum wiring got a bad rep back in the 70's when some fires were attributed to it, but since then the wire manufacturers have been using alloyed aluminum whose coefficients of thermal expansion much more closely matches that of copper. The previous mismatch of coefficients was responsible for some series arc faults, but now the hazard has been ameliorated as long as you use terminals that are aluminum or dual copper and aluminum rated.

  4. #14
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    Dec 2012
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    Placerville, CA, USA
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    Quote Originally Posted by ggunn View Post
    Aluminum wiring got a bad rep back in the 70's when some fires were attributed to it, but since then the wire manufacturers have been using alloyed aluminum whose coefficients of thermal expansion much more closely matches that of copper. The previous mismatch of coefficients was responsible for some series arc faults, but now the hazard has been ameliorated as long as you use terminals that are aluminum or dual copper and aluminum rated.
    But even those terminations will perform better with the newer wire alloy.
    They should work with the old stuff, but workmanship in installation is even more important then.

    You may also see terminations that are rated for Cu or Cu-clad Al only. Not for use with straight Al.

  5. #15
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    Apr 2005
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    Quote Originally Posted by bluecollar84 View Post
    What does the NEC code say about existing aluminum wiring 20amp 12 gauge ? Does it have to be removed if found ? Can I add to that circuit with copper using special lug nuts ? I have to add an outlet off existing aluminum wiring . What are your thoughts or do I have to run a new branch circuit ?

    If possible I try never to add anything to a circuit wired with AL. Sure it's legal to do so but may end up with more trouble than running a new circuit.

    To be honest in this area there is not much Al left or there wasn't that much to start with ( don't know which ).
    The 95% of people that you can't trust give the other 5% a bad name.

  6. #16
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    Quote Originally Posted by GoldDigger View Post
    But even those terminations will perform better with the newer wire alloy.
    They should work with the old stuff, but workmanship in installation is even more important then.

    You may also see terminations that are rated for Cu or Cu-clad Al only. Not for use with straight Al.
    I intended for my comments to be a Boolean AND, i.e., use newer wire AND use Al rated terminals.

  7. #17
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    Quote Originally Posted by ggunn View Post
    I intended for my comments to be a Boolean AND, i.e., use newer wire AND use Al rated terminals.
    Which is not possible when existing wiring is old Al. Would you always rewire?

    mobile

  8. #18
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    Jan 2016
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    Jax, Fl
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    Quote Originally Posted by MNSparky View Post
    I get this question A LOT. It's not the wire that's unsafe, it's the terminations. Devices or wire connectors not listed for use with aluminum or tying AL and CU together. I know the Ideal purple wirenuts are listed to do that but I've seen too many fail due to the AL and CU touching. Get yourself some AlumiConn connectors and a tourque screwdriver.
    Anyone had issues with box fill when using alumicons? Some of the older homes here in FL has the small metal boxes and it's pretty tough to get three alumicons to fit especially if you have to install a gfi with them.

  9. #19
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    Dec 2016
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    Minneapolis, MN
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    Quote Originally Posted by 1haz View Post
    Anyone had issues with box fill when using alumicons? Some of the older homes here in FL has the small metal boxes and it's pretty tough to get three alumicons to fit especially if you have to install a gfi with them.
    Yes, that's a big problem. I usually include time and materials in my quotes to change out some boxes if need be. We also end up doing larger J-boxes in the attic and unfinished areas sometimes. You get really good at laying everything flat and neat in the back of a box when using them!

  10. #20
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    Quote Originally Posted by 1haz View Post
    Anyone had issues with box fill when using alumicons? Some of the older homes here in FL has the small metal boxes and it's pretty tough to get three alumicons to fit especially if you have to install a gfi with them.
    maybe the answer is to use the existing box as a jbox by adding a cover and put the device in a box next to it using one of the boxes designed for installation in existing walls. paint the cover and it is barely noticeable.
    Bob

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