breaker size for 12 gauge wire

Discussion in 'Electrical Forum discussion & Blog' started by whoazone, Jul 15, 2008.

  1. whoazone

    whoazone New Member

    Messages:
    5
    What is the largest breaker I should use on 12 gauge wire? How about 14 guage wire?
  2. jbfan74

    jbfan74 Electrical Contractor

    Messages:
    131
    Location:
    Newnan, GA
    #12=20 amp breaker
    #14=15 amp breaker
  3. whoazone

    whoazone New Member

    Messages:
    5
    Can 10 gauge wire handle a 30 amp breaker?
  4. Speedy Petey

    Speedy Petey Licensed Electrical Contractor

    Messages:
    996
    Location:
    NY State, USA
    Basically, yes.
  5. 30 amp breaker with 10g wire is usually what is used for an electric water heater.
    Mike
  6. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,615
    Location:
    Cave Creek, Arizona
    wires

    Are you asking for a specific appliation, or just fishing for information?
  7. pudge565

    pudge565 New Member

    Messages:
    24
    If using ROMEX® those answers are correct but if its not ROMEX® it depends on the wire insulation type and if it needs to be derated.
    Last edited by a moderator: Dec 7, 2011
  8. Chris75

    Chris75 Electrician

    Messages:
    608
    Location:
    Litchfield, CT


    What are you talking about? Try reading 240.4(D)
    Last edited by a moderator: Dec 7, 2011
  9. pudge565

    pudge565 New Member

    Messages:
    24
    Yes my bad I don't know what I was thinking maybe flexible cords?
  10. Johnny C

    Johnny C Electrician

    Messages:
    23
    Location:
    Mass. & now Virginia Beach, VA
    Breaker size for # 12 wire

    You have not specified what type load and what type overcurrent protection is provided ie. (circuit breaker or fuse) the #12 conductor is supplying. If the circuit is supplying a motor load, the NEC allows a CB or Fuse rated greater than the conductor ampacity.
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