Does 12-2 copper carry same current as 10-2 aluminum

Discussion in 'Electrical Forum discussion & Blog' started by kb8man, Jun 11, 2008.

  1. kb8man

    kb8man New Member

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    In the process of replacing aluminum wire in house, came across 10-2 Al need to know if 12-2 copper will work to switch it out with. Also have a hugh black wrapped Al wire supplying the washer and dryer outlets, (no 220 plug) it is marked 10-3 with ground what can I switch it out with. Thanks.
  2. Chris75

    Chris75 Electrician

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    Location:
    Litchfield, CT
    # 10 AL is good for 25 amps
    # 12 CU is good for 20 amps

    What was the #10 AL feeding?


    The dryer circuit can be replaced with #10-3 cu, new 4-wire receptacle and cord.
    The washer must be a dedicated circuit, 12-2 cu.
    Last edited: Jun 11, 2008
  3. kb8man

    kb8man New Member

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    12-2 copper and 10-2 AL

    The 10-3 Al feeds a plug the washer and or dryer plugs into off a 20amp circuit. Then a 10-2 Al feeds off that plug into another one which the washer/dryer can plug into (about a 3 foot stretch). Dryer is gas. Electric is only for pilotless ignition and computer programs etc. for the settings.
    Last edited: Jun 11, 2008
  4. Chris75

    Chris75 Electrician

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    608
    Location:
    Litchfield, CT

    just rip out all the aluminum you can, save yourself some headaches down the road, insurance companies do not like it.



    If your going to keep the gas dryer, then just run a 12-2 homerun and install a duplex, half for the washer and half for the dryer.... Meets code and your good to go.
  5. Mikey

    Mikey Aspiring Old Fart, EE, computer & networking geek

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    Is this a new NEC2008 requirement?
  6. Chris75

    Chris75 Electrician

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    608
    Location:
    Litchfield, CT
    Nope 2002, (maybe earlier) and I never should have said a washer needs a dedicated circuit, a laundry receptacle is required...
    210.11(C)(2) and 210.52(F) requires a receptacle outlet served by a 20A branch circuit to be provided in the laundry area of a dwelling unit.
    210.11(C)(2).jpg
    Last edited: Jun 11, 2008
  7. jwelectric

    jwelectric Electrical Contractor/Instructor

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    What turns the tub of the dryer?
    I would bet that it is an electric motor :)
  8. Mikey

    Mikey Aspiring Old Fart, EE, computer & networking geek

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    Now I'm with you.
  9. kb8man

    kb8man New Member

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    Thank you for all the responses.

    I am in the process of replacing the Al with Cu that was the basis behind the original post. Just wasn't sure about the wire size necessary.

    Here is another twist to this saga.... Allmost all of the plug outlets are Al while the light circuits are Cu in my house why would they do this? The house was built in 1968.

    After turning the breaker off and testing the plugs in question from the original post, I presided to start taking out the wire. When I pulled the wire up from the metal box it sparked (hugh) and blew the breaker. I had previously checked and made sure the circuit was off, why did this happen? Could the original owners split a 220 circuit and left half unaccounted for? What is the explanation of this. Breaker leading to the plugs was off, no power at either plug but hot wire sparking and blew breaker (which have not been able to reset). There is no 30 amp receptacle anywhere near the laundry area......

    And yes the dryer drum is turned by an electric motor........ my bad. :)
    Last edited: Jun 13, 2008
  10. Mikey

    Mikey Aspiring Old Fart, EE, computer & networking geek

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    Were you pulling the 10-3 or the 10-2? I don't understand what you meant when you said that you first turned the breaker off, but then during the course of the work the breaker blew. Same breaker? Hard to blow a breaker that's already off, I would think.

    In 1968, the reason for using aluminum was -- it was cheaper than copper. Or maybe somebody got a deal on the Al they used for the receptacles, but the lighting circuits might have been 14-2, and cheap enough. Al got a bad rap for starting fires and killing people, mostly due to bad installation between 1965-1973, after which time the industry changed practices, tooling, and fixtures to accomodate aluminum's quirks.

    Check the following URL for interesting info:
    http://www.heimer.com/information/aluminum_wiring.html
  11. kb8man

    kb8man New Member

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    I was pulling the 10-2 al which has/was pulled from the receptacle which terminates the 10-3 Al. I shut the breaker down which powers both size wires, proceeded to pull out the 10-2 and sparked tripping the breaker. Maybe the diagram below will help straighten things out. Was trying to pull the wire from the box on the right to continue to the box on the left......

    Attached Files:

  12. Mikey

    Mikey Aspiring Old Fart, EE, computer & networking geek

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    Location:
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    Sounds like one leg of the 10-3 was still live. Tell us more about how the 10-3 was terminated in the panel.
  13. kb8man

    kb8man New Member

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    As far as I can tell it is terminated on one 20 amp breaker... at least that is what it looks like.................
  14. kd

    kd New Member

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    207
    Do you mean that you tested a wire with a hot stick, it indicated dead, then when you pulled it out of the box it sparked? When working on an old house, I recommend shutting off all circuits except for one circuit that feeds a single outlet at the service box for tool power and for a cord to the refrig.
  15. Alectrician

    Alectrician DIY Senior Member

    Messages:
    689
    Call an electrician. Somebody some day is going to have to fix your stuff.

    Seriously, if you don't know enough to turn off the power properly you are going to hurt yourself of worse, somebody else in the future. Can you live with that?
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