Wiring a 220 Volt GFI breaker?


Old 01-07-02, 02:02 PM
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Wiring a 220 Volt GFI breaker?

I got a heater in a bathroom that I would like to switch from a standard 220 Volt 20 amp breaker to a 220 Volt 20 amp GFI breaker. Only problem is wiring it in. It has the two wires that run to the heater (either side of the 220 volt) and a ground. To wire in a GFI I would have to pull the ground off the ground bus in the breaker box and wire that directly to the GFI breaker and then run the curly white wire back to the Ground Bus bar. Is that legal? It is kind of a weird situation.
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Old 01-07-02, 03:42 PM
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If I remember right the pigtail coming from the 220 volt GFI breaker is a neutral not an equipment grounding wire.

You need to connect black and white wires going to the heater to the two hot screws of the breaker. The connect the pigtail of the breaker to the neutral bar and the bare wire going to the heater to the grounding bar. You will not have a white neutral in this branch circuit serving a wall heater. There will be a neutral lug on the GFI breaker that will remain empty.

Hope this helps

Old 01-08-02, 10:21 AM
Gary Tait
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It is a neutral only. GFI or not, the EGC (bare ground) ALWAYS
connects to the ground bus.
Old 01-08-02, 11:48 AM
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I might be missing something here, but I'll ask the question anyway. Why do you want to put a 220 volt heater on a gfci circuit breaker? Are the wires to the heater black, white and green (or bare)? The equipment grounding conductor (green or bare) must remain connected to the heater.
Old 01-08-02, 05:20 PM
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more information

I was never planning on pulling the ground wire off the heater. All I am concerned about is how to wire it up when it reaches the main breaker panel. The reason I wanted to put a GFCI breaker on the circuit is that it is within reach of the bathtub. I could possibly imagine a case where water might get in the heater and cause a problem that a GFCI breaker should catch. I still wonder if it will work to not have anything screwed into the neutral lag on the GFCI breaker. From what I understood, the breaker uses a transformer to monitor the current running between the hot wires and the neutral. When it senses current running on the neutral it trips the breaker in less than 6 ms. What I don't get is how it works if there is no neutral wire like there is in my heater. I have wired up GFCI 220 volt circuits before but they have always had a neutral AND a ground. (Long answer to a short question)
Old 01-09-02, 03:02 AM
Matt Marsh
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The 2-pole GFCI breaker will work just fine with no load neutral connection. The line neutral pigtail must be connected only so that the "test" button will work.

The GFCI breaker monitors current on all three "load" terminals. If at any given instant, a certain amount of current is leaving one hot terminal, that same exact amount (within 4ma) must return on the other hot or the neutral terminal, or a combination of both.

Connecting the equipment grounding conductor to the "load" neutral terminal of the GFCI would be defeat the whole intent of the GFCI breaker. If a ground fault occured at the heater, the returning current to the "load" neutral terminal via the equipment ground would tell the breaker that everything is still AOK. As long as this current was less than the rated ampacity of the breaker, it would not trip.


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