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Thread: NEC Code lets me to splice a 700 ' 1/0 cable to 8 AWG to land it on a Panel Breaker?

  1. #11
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    Quote Originally Posted by ggunn View Post
    No, you must increase your EGC by the same ratio as you increased your current carrying conductors, not to the same size as they are.
    It depends on the OCPD used for the 120 volt circuit. In this case if the circuit is 15, 20, or 30 amps (which requires an EGC the same size as the phase conductors) the EGC is increased at a ratio of 1 to 1 or the same size tkb stated.
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  2. #12
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    Quote Originally Posted by infinity View Post
    It depends on the OCPD used for the 120 volt circuit. In this case if the circuit is 15, 20, or 30 amps (which requires an EGC the same size as the phase conductors) the EGC is increased at a ratio of 1 to 1 or the same size tkb stated.
    Correct.

    Now take OP's same circuit, assuming copper conductors and put a 150 amp breaker at the beginning - then put a 15,20 or 30 amp breaker at the load end of that 1/0 and short run of 14,12 or 10 AWG to the load and you still have essentially same thing but can 6 AWG EGC instead of a 1/0 EGC with the feeder segment of this.

    Totally makes sense doesn't it?
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  3. #13
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    Quote Originally Posted by infinity View Post
    It depends on the OCPD used for the 120 volt circuit. In this case if the circuit is 15, 20, or 30 amps (which requires an EGC the same size as the phase conductors) the EGC is increased at a ratio of 1 to 1 or the same size tkb stated.
    Well, OK, but if the EGC is already the same size as the CCC's, increasing it by the same ratio means that it will still be the same size as the CCC's. The rule isn't different.

  4. #14
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    Quote Originally Posted by ggunn View Post
    No, you must increase your EGC by the same ratio as you increased your current carrying conductors, not to the same size as they are.
    Since the OP inferred that this was a 20 amp circuit, then the EGC would be the same size as the CCC, so since they are the same size the 1:1 ratio would mean that they would be the same size when increased for VD.
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  5. #15
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    Quote Originally Posted by tkb View Post
    Since the OP inferred that this was a 20 amp circuit, then the EGC would be the same size as the CCC, so since they are the same size the 1:1 ratio would mean that they would be the same size when increased for VD.
    No, he implied, we infer as such...

    But, yes you are correct. Full bore on the EGC here.
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    Derek

  6. #16
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    Quote Originally Posted by tkb View Post
    Since the OP inferred that this was a 20 amp circuit, then the EGC would be the same size as the CCC, so since they are the same size the 1:1 ratio would mean that they would be the same size when increased for VD.
    But if one ran a "feeder" for most the length of the circuit (with overcurrent protection that corresponds to the feeder conductor ampacity) and a smaller, short branch circuit at the load end, you have same length, you have same size current carrying conductors but can now reduce the EGC to whatever it says in T250.122 and that is code compliant.

    They don't trust the 20 amp breaker to trip in reasonable time unless you also run a 1/0 EGC, but we can put a 150 amp breaker in there instead and reduce the EGC to 6 AWG.
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