GFCI 120v/220v

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RRSUPT

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May be in the wrong spot but here goes.

Wife's employer is installing a pedicure chair with a massaging back, I imagine this will be 220 but can be ordered in 120 also.
My question is say she goes with a 120v unit....she has a general purpose recep. circuit where we'll replace the recep with a GFI, if pigtailed will that GFI read off the other devices and cause it to fault constantly?Shouldn't this GFI be a dedicated circuit?

If she goes with a 220v, there is no 220v GFCI recep and even if GFI protection was needed which i feel would be, we'd install a GFI breaker, BUT that won't work without a "neutral".

So how would you GFI protect a 220v pedicure chair? Or is it simply not required, needed?
 
You could, if you wanted to (it's not an NEC requirement) use a 2-pole GFCI breaker. If there's no white wire to the chair, then all you need to do is land the white wire from the GFI to the neutral bar.
 
peter d said:
Why would it be required to?

And it's "240", not "220." :)
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yeah I know, just got through reading pedicure chair specs(didn't help much) just like it's 120 not 110, and 480 not 460.

I guess it just seems to me a GFCI would be safer, as it would monitor the difference between hot/ground, whereas 240 wouldn't, but the 240 would trip anyway, huh?:-?
 
480sparky said:
You could, if you wanted to (it's not an NEC requirement) use a 2-pole GFCI breaker. If there's no white wire to the chair, then all you need to do is land the white wire from the GFI to the neutral bar.
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Yeah I've done that before :roll: but isn't that pointless? That defeats the purpose of a GFI, so I'd waste money on a breaker???
 
RRSUPT said:
yeah I know, just got through reading pedicure chair specs(didn't help much) just like it's 120 not 110, and 480 not 460.

I guess it just seems to me a GFCI would be safer, as it would monitor the difference between hot/ground, whereas 240 wouldn't, but the 240 would trip anyway, huh?:-?
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A 2-pole breaker will monitor any hot-to-ground leaks. That, by definition, would be a ground fault. Anything over 5ma should trip it.

RRSUPT said:
Yeah I've done that before :roll: but isn't that pointless? That defeats the purpose of a GFI, so I'd waste money on a breaker???
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What is pointless?... providing an amount of safety above and beyond the NEC?
 
RRSUPT said:
I guess it just seems to me a GFCI would be safer, as it would monitor the difference between hot/ground, whereas 240 wouldn't, but the 240 would trip anyway, huh?:-?
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A 2-pole GFCI breaker will work without a branch circuit neutral. However, the neutral connection on the GFCI breaker must still be connected.

As for the pedicure chair, you can certainly GFCI protect it if you want.
 
480sparky said:
A 2-pole breaker will monitor any hot-to-ground leaks. That, by definition, would be a ground fault. Anything over 5ma should trip it.



What is pointless?... providing an amount of safety above and beyond the NEC?
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no no, i thought installing a GFCI breaker without a circuit neutral would be the same as a non-GFCI breaker, hence not GFCI protected.
 
RRSUPT said:
no no, i thought installing a GFCI breaker without a circuit neutral would be the same as a non-GFCI breaker, hence not GFCI protected.
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It will still work just fine. Without the circuit neutral, the GFCI breaker will only be able compare the line to line current. If it goes out of balance, it will trip.
 
peter d said:
It will still work just fine. Without the circuit neutral, the GFCI breaker will only be able compare the line to line current. If it goes out of balance, it will trip.
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well I learned something today! That's good to know, so in my case I'd rather install a GFCI breaker, safer the better. Thanks!
 
RRSUPT said:
well I learned something today! That's good to know, so in my case I'd rather install a GFCI breaker, safer the better. Thanks!
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There's a lot of 240-v (no neutral) loads that use GFI protection. Pool pumps, fountains, spas & hot tubs......
 
480sparky said:
There's a lot of 240-v (no neutral) loads that use GFI protection. Pool pumps, fountains, spas & hot tubs......
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I figured I had to be missing something as most would want the protection but yet there is no 240v GFI plug and at the time I didn't know a GFI breaker would work properly without a branch circuit neutral.
 
RRSUPT said:
I figured I had to be missing something as most would want the protection but yet there is no 240v GFI plug and at the time I didn't know a GFI breaker would work properly without a branch circuit neutral.
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It will still work as designed. You will just have the one terminal on the breaker that is not used.
 
RRSUPT said:
no no, i thought installing a GFCI breaker without a circuit neutral would be the same as a non-GFCI breaker, hence not GFCI protected.
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rrsupt,

You misunderstand how a gfci works. A gfci monitors all of its load conductors, and trips on 'net current' on the set. Net current means any current that is not balanced across the entire set of conductors.

In the case of the most common 120V gfci devices, this implies 'hot balances neutral' as you understand and expect. But in a 240V 2 pole gfci breaker this means that all three load conductors will be monitored. If current flowing on each conductor is not balanced by the other two, then you get a trip. Say the load has no connected neutral...then the gfci will simply monitor the balance of the two 'hot' wires. If current ends up flowing elsewhere, you get a trip, even with no neutral connected to the load.

-Jon
 
To add: A GFCI device doesn't "compare" hot to neutral per se, it simply monitors the current through all of the circuit conductors, two or three. As long as the current through any conductor returns on the other(s), the net is zero.

If any current through any conductor "leaves" the circuit on the load side of the GFCI device, that portion of the total current is sensed and trips the device. The only requirement is having a grounded electric service or supply.
 
LarryFine said:
Whatever it is, it should be two times 120v.
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Exactly, any system that has a 120 volt component to ground would have either a 208 volt or 240 volt phase to phase voltage. It could never be 120/220.
 
infinity said:
It could never be 120/220.
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Yeah sorry about that. It was a lame joke based on the idea of nominal voltages. For example a circuit supplying anything from 110v to 120v could be called 110 or 120. Just like 220-240 and 440-480. Something I read on a utility company's website indicated it's a nominal voltage (115v) plus or minus 10%.
 
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