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Thread: Dumb GFCI question

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    Dumb GFCI question

    If a double pole GFI, the kind you install in the main breaker panel, is rated at 30 amps, is that 30 amps for EACH leg or 30 amps total, 15 amps for each leg?

    Thanks.

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    JasonLion's Avatar
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    Re: Dumb GFCI question

    30 amps at 240 volts is 7,200 watts. That same power, 7,200 watts, would be drawn by a 60 amp load at 120 volts. So, at some level the answer is 30 amps on each leg. However, if you have a GFCI breaker you can't split the two legs, you have to run a 240 volt load, so the answer wouldn't matter. If it is not a GFCI breaker then you could in theory split the legs and get 30 amps at 120 volts from each, for a total of 60 amps, though doing so is usually a code violation.
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    Re: Dumb GFCI question

    Thanks. Just wanted to make sure I understood the rating properly. Don't intend to split the legs.

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    Re: Dumb GFCI question

    OK, another dumb question about the GFCI. There are three posts plus the pigtail on this 2 pole GFCI. The bottom one is for the "return" white wire neutral from the load. HOWEVER, with 230V service you don't use the white wire, correct? At least there is no place on the pump to hook it up. There are three terminals plus a green screw ground there: Common (one 120V line), high and low for the switched two speed, using the other 120V line. This is switched in the T106 timer such that only either high or low gets the feed from the other line at a time.

    So if the white wire is dead ended, how can the GFCI function? Should I wire the white wire to the green screw inside the pump along with the green wire? It would seem like doing this would cause leakage to absolute ground which would trip the GFCI instantly.

    Sorry for these dumb questions. I have hooked up a GFCI to a spa pump before but there was a terminal in that pump for the white wire. This two speed motor doesn't have a terminal for the white wire, just the ones I listed above.

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    Re: Dumb GFCI question

    I haven't used one of these quite yet for 230-240 VAC. Is the third post green? If it's marked green then they want the ground on it.

    The recepticle normally uses this as part of the TEST button to purposely pass electricity on the wrong wire (The GROUND as if someone could be electrically in danger of getting hurt in which then the recepticle shuts off).

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    Re: Dumb GFCI question

    The problem is not the circuit, the problem is that there is no terminal on the two speed motor for the white (neutral). In another thread it was pointed out that 230 V does not use a neutral but the GFCI requires one in order to function. There's no problem figuring out how to wire at the GFCI, the problem is how to wire at the pump.

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    Re: Dumb GFCI question

    So the color of the screw is not green? I think from memory this would make the screw color silver if they want a neutral on it as I think brass is hot.

    If they do want a neutral on the GFCI in your case it should actually work without it because you aren't using the neutral.

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    Re: Dumb GFCI question

    That can't be correct because the GFCI measures current difference between the neutral and hot. They need to be the same. If they aren't the same, which would obviously be the case if the neutral isn't hooked up, it would immediately trip. Which is what it is doing.

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    Mod Squad JohnT's Avatar
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    Re: Dumb GFCI question

    There are normally 2 neutral connections on a 220V GFCI. One is for the GFCI, and the other is out to the load. With a 2 wire load, you just leave the out neutral unconnected and connect the pigtail to the panel neutral.

    A 220 GFCI monitors both hots and the neutral looking for a zero sum. If the neutral isn't used, it still looks for a zero sum on the hots.
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    Mod Squad Bama Rambler's Avatar
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    Re: Dumb GFCI question

    Those breakers were designed to be used on appliances that have 120 volt controls so that's what the neutral connection is for.
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    Re: Dumb GFCI question

    Quote Originally Posted by JohnT
    There are normally 2 neutral connections on a 220V GFCI. One is for the GFCI, and the other is out to the load. With a 2 wire load, you just leave the out neutral unconnected and connect the pigtail to the panel neutral.

    A 220 GFCI monitors both hots and the neutral looking for a zero sum. If the neutral isn't used, it still looks for a zero sum on the hots.
    There is a diagram in the accompanying literature for two wire 220V. Load neutral is left unused and the green screw on the motor is connected to the green which goes back to the panel. It is as John says, you don't connect the load neutral. Hope the fact that one leg is being switched between high and low speed will not cause this thing to trip.

    It is rated for 240V service according to the literature that came with it.

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    JasonLion's Avatar
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    Re: Dumb GFCI question

    It will be fine. Neither switching the pump on/off or changing speed will trip the CGFI breaker (unless something else is also wrong).
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    Re: Dumb GFCI question

    As John T. said, hook both loads to the breaker as you normaly would. Hook the pigtail to the neutral bar. The pigtail is for the test circuit in the breaker. Whithout it it will not trip on test (at least on the ones I have used).

    In a standart 220/240 circuit the neutral is the negative side of the opposite phase. The breaker watches for the current flow both ways thru the circuit and trips if there is any current differential The pigtail is used as the test path for the current differential when the test button is pressed
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    Re: Dumb GFCI question

    In a 240V circuit - you would normally have 4 wires - Ground, Hot 1, Hot 2, and Neutral. The colors should be Bare/green , Black, Red, white. However, for a 240V pool pump, you don't need to run a neutral.

    Now, with that kind of a 240V GFCI breaker - you COULD safely run a 120V pump - I know I can on my setup - just disconnect the red wire, jumper it to a neutral terminal in the timer, then power it back on. In this case - my GFCI gets power from the red/black in the circuit panel, and the little white pigtail is connected to the neutral bar, There are also 3 slots that connect to a 12/3 wire as well.
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