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A couple circuit breaker questions

Discussion in 'Electrical Engineering' started by John, Nov 3, 2003.

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  1. John

    John Guest

    1) I know you can only put two wires in a breaker that is designed for it;
    but do they say they can hold two, or do they say they can only hold one;
    which way does it work? If it can hold only one, I can just still use
    two circuits in one breaker with a jumper, can't I? (I have two outdoor
    outlets on their own circuits. One has never been used, and the other just
    has some low voltage lighting on it and a few christmas lights in season.
    Since I need some space in the panel, it seems reasonable to consolidate
    them. If I can't use the jumper, I guess I will just abandon the unused
    outlet; but that seems wrong somehow.)

    2) Do GFCI breakers require power before you can set them on, like GFCI
    outlets? I have a circuit that is flaky, and everything but the GFCI
    breaker seems okay. When I swapped the breaker with a spare, it is okay, so
    I figure it must be the breaker. It will stay in the on position when
    disconnected; does that mean it is bad? The spare is 20a, and it should be
    15a, so I need to buy a new one if the old 15a is broken. (I figure the
    chances of a 20a breaker being a fire hazzard on a lightly used #14 circuit
    for a few days is extremely small, no?)

  2. jim

    jim Guest

    The only issue with putting more than one wire (or a very large wire) into a
    breaker is it will affect the trip time. The wire acts as a heat sink.
    The bigger the wire, the slower the breaker.
    Putting two #12 wires in a 20 amp breaker or 2 #14 in a 15 amp is not a
    problem. It may be against some local codes.
    Jumpering the one wire from the breaker to two circuits is not a big deal
    either. This would probably violate code though. The wiring areas for
    panels are not sized considering their use as a junction box, but one
    splice isn't going to hurt. If you make the splice outside the panel,
    there is no violation (unless of course you overload the circuit, but it
    doesn't seem likely from your description.
  3. John

    John Guest

    I thought it had to do with making contact with two wires at once rather
    than with just once.

    The breaker in question, a 20a GFCI, says it can accept #8 wire, so it
    shouldn't have any heat problems with 2 #12s.
    Thank you.
  4. daestrom

    daestrom Guest

    Of the GFCI's I've seen, they mechanically latch/reset. So you can reset
    them with them in your hand (no power). If it won't reset in your hand, it
    is definitely bad.

    They need power to trip/test, so it must be installed to 'test' the GFCI
    tripping. If you install it in the panel (and the 'pigtail' to the neutral
    bus), but leave the circuit 'hot' and 'neutral' wires off, it should not
    trip. If it keeps tripping then (with no downstream circuit connected), it
    must be bad. If it stays 'on' under those conditions, connect the circuit
    'hot' and 'neutral'. If it keeps tripping and won't stay reset then (with
    circuit connected), you may have a ground on the circuit.

    Some GFCI's will trip if the neutral is grounded downstream, others will
    not. Some have a 'signal generator' that puts a minute signal on the
    neutral (and hot) and looks for current flow downstream side of neutral,
    return through Equipment Grounding Conductor (EGC) back to neutral bus.
    Others (older??) don't have this feature.

    So before you scrap it, be sure your circuit's neutral isn't connected to
    ground somewhere besides through the GFCI.

  5. John

    John Guest

    I have replace it with a plain breaker and a GFCI breaker. Haven't had a
    nuisance trip in 3 days; however, maybe the old one looked for a the the
    neutral to ground connection and the new one doesn't. I will put it in
    another circuit to see if it fails there also.
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