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Thread: Can I use 10/2 cable on a regular 12 or 20amp circuit?

  1. #1
    DIY Junior Member PabNYC's Avatar
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    Default Can I use 10/2 cable on a regular 12 or 20amp circuit?

    I think the answer is yes but i just want to make sure.

    I already have a 10 gague home run that goes to my garage. Currently it is disconnected at the panel and in the garage it just runs to a box where the wires are capped. Can I just connect this to a 20 amp breaker in the panel and put a regular receptical at the garage end? GFCI of course : )


    Thanks

  2. #2

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    10/2 with ground I presume?

    Safety wise, it is fine to use a larger than required wire.

    Mechanical wise, a #10 should fit in the breaker OK (look at specs on breaker), but might not in the GFCI. The new GFCI's I've seen have a hole in the back for the wire and you tighten the connection with the screw on the side - can't wrap the wire around the side and I don't think you would want to try that with a #10 anyway. But the hole on one I have here looks like #12 is the largest it will accept, but mine is a 15 amp. Maybe a 20 amp GFCI would accept a #10? I don't know?

    I don't see wire sizes when looking at the GFCI specs on the internet.

    Then cramming everything into the electrical box wise... I would use a deep double gang box with a single gang plaster ring.

  3. #3
    DIY Junior Member PabNYC's Avatar
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    Thank you Billy Bob

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    Extreme DIY Homeowner Scuba_Dave's Avatar
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    You could always pigtail #12 wire on the end for connections
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  5. #5

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    NO PIGTAILING. What happens when somebody comes in and sees that 10-2 and decides to up the breaker? A responsible person would check first, but a lot would see the 10-2 and add a new breaker, overloading any pigtailed 12ga.

    Cooper GFCI's can handle 10ga solid or stranded in the backwire holes and I believe 8ga in the screw terminals.
    Last edited by iminaquagmire; 03-04-2009 at 10:21 AM. Reason: fixed spelling error
    I consider myself an accomplished DIY'er. I don't know everything but help where I can. I'm not a pro, but like to think I'm professional.

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    Extreme DIY Homeowner Scuba_Dave's Avatar
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    Quote Originally Posted by iminaquagmire View Post
    NO PIGTAILING. What happens when somebody comes in and sees that 10-2 and decides to up the breaker? A responsible person would check first, but a lot would see the 10-2 and add a new breaker, overloading any pigtailed 12ga.

    Cooper GFCI's can handle 10ga solid or stranded in the backwire holes and I believe 8ga in the screw terminals.
    Duh, the same thing that happens when somebody ups the breaker without checking in the 1st place with 20a devices in place
    #10 wire is commonly used for long 20a runs
    When have you last seen a 30a residential outlet 120v
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    Radon Contractor and Water Treatment 99k's Avatar
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    Quote Originally Posted by Scuba_Dave View Post
    Duh, the same thing that happens when somebody ups the breaker without checking in the 1st place with 20a devices in place
    #10 wire is commonly used for long 20a runs
    When have you last seen a 30a residential outlet 120v

    I'm no electrician but I have to agree ... pigtail is fine. My electrician does this.

  8. #8

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    Attached or detached garage?
    rgsgww

  9. #9

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    Quote Originally Posted by Scuba_Dave View Post
    Duh, the same thing that happens when somebody ups the breaker without checking in the 1st place with 20a devices in place
    #10 wire is commonly used for long 20a runs
    When have you last seen a 30a residential outlet 120v
    I've never seen a 30A residential receptacle. That doesn't mean somebody down the line can't change the line to something else or add a junction elsewhere. Like I said, a responsible person would check before changing a breaker, but I'll never pretend everybody is responsible or smart.

    You can put aside the average person's intelligence anyway, as there is no need to pigtail in this instance. 10ga wire will connect just fine to either Leviton or Cooper GFCI receptacles.
    I consider myself an accomplished DIY'er. I don't know everything but help where I can. I'm not a pro, but like to think I'm professional.

  10. #10
    Extreme DIY Homeowner Scuba_Dave's Avatar
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    Quote Originally Posted by iminaquagmire View Post
    I've never seen a 30A residential receptacle. That doesn't mean somebody down the line can't change the line to something else or add a junction elsewhere. Like I said, a responsible person would check before changing a breaker, but I'll never pretend everybody is responsible or smart.

    You can put aside the average person's intelligence anyway, as there is no need to pigtail in this instance. 10ga wire will connect just fine to either Leviton or Cooper GFCI receptacles.
    And you can't possibly plan for everything somebody else might do
    Telling someone they can't do it is wrong
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  11. #11
    Moderator & Master Plumber hj's Avatar
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    Default back wiring

    A few years back restrictions were placed on back wired devices. The holes could not accept a larger wire than the device was rated for. #14 ONLY for 15 amp items, #14 or smaller for 20 amp ones. Therefore the #10 wire will not fit into a back wired receptacle, but would work with screw terminals or devices with wired connectors.

  12. #12

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    The number 10 wire is good for 30 amps. That is max. Yes you can use it for a smaller breaker.

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    Electrician Chris75's Avatar
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    Quote Originally Posted by iminaquagmire View Post
    NO PIGTAILING. What happens when somebody comes in and sees that 10-2 and decides to up the breaker? A responsible person would check first, but a lot would see the 10-2 and add a new breaker, overloading any pigtailed 12ga.

    Cooper GFCI's can handle 10ga solid or stranded in the backwire holes and I believe 8ga in the screw terminals.

    Your a goof ball. Who cares what the next idiot does?

  14. #14

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    The next idiot may tap off the service conductors, how am I suppose to prevent that?
    rgsgww

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    Remodel Contractor GabeS's Avatar
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    20 amp breaker means 20 amp circuit. The breaker determines the amps of the circuit, not the wire size. If someone switches to a higher breaker, then they don't know what they are doing and shouldn't be doing it. How can you prevent them from sticking a live wire in their mouth?
    Gabe

    Don't follow my advice, I only know a thing or two about a thing or two.

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