Hello everyone, I ran into this stuation a few days ago. I am installing the motors for a jacuzzy which come with three wires, 2 hots and 1 ground. when I tried to connect a gfci cb it kept tripping. Since I dont a neutral for the load, I am trying to play with the ground to get my zero reference voltage. I am not sure if this will work though. any input from the zen masters will be appreciated.
Estman, don't forget that you must connect the GFCI breaker's white to the neutral bus, even if the load has no neutral, and the EGC must be tied directly to the neutral (or separate ground bus if there is one) just as with any circuit.
As Larry said, the GFCI's white neutral connects to the neutral bus. The neutral terminal on the GFCI has no connection at all--there's no neutral on the circuit, so there isn't supposed to be any current flow through that terminal.
Also, GFCIs don't work with "reference voltages"s; they work by summing all the current passing in and out of the circuit, which should sum to zero. If it doesn't sum to zero, that indicates that there's a ground fault somewhere, and the GFCI trips. So any connection you make to the neutral terminal will generate an unbalanced condition, tripping the GFCI.
[This message has been edited by SolarPowered (edited 08-06-2005).]
I had a similar problem...which the tub maker was just certain was caused by my mis-connecting the GFI breaker. So I began disconnecting various parts of the tub's systems- until I could say "it works fine until the stereo is connected." Only then did they send some one out to replace the faulty item.
I know it's hard to believe, but sometimes GFCI's trip and fuses blow- because they're supposed to!
If your load has two 'hot' wires and no neutral, then one would assume that all current is normally carried by the two 'hot' wires alone, yes? Therefore, what is needed is to use a 2-pole RCD (GFCI) and run each 'hot' through one pole of the RCD.
The RCD works on by tripping on a current imbalance between the two conductors - if the current in one 'hot' is not the same as in the other 'hot' then the difference must be going to earth.
FWIW, this approach also works with 3-pole RCDs in a 3-phase circuit without neutral.