120V from a 240V GFCI

[Little Bill]

Am I correct in thinking you can't run a piece of 120V equipment off a 240V GFCI without tripping the GFCI?

I have a timer for a pool pump that is 240V. It is fed from a 240V GFCI. They have a UV light for cleaning the pool that can only be on when the pump is running. Normally I do this with the timer but the cleaning equipment is usually also 240V.
I'm thinking if I tried to take 120V off one of the load sides of the timer the GFCI will see that as a fault or imbalance since I would also have a neutral. The current on the 120V would return on the neutral and not the other leg of the 240V therefore cause the GFCI to sense an imbalance.
Is this correct or is my brain "fuzzy" again?

 

[iwire]

Is the load neutral connected to the GFCI or directly to the neutral bar in the panel?

 

[jim dungar]

Am I correct in thinking you can't run a piece of 120V equipment off a 240V GFCI without tripping the GFCI?

Yes, as long as the neutral is 'run through the GFCI". Use a 3-wire device and you should be all set.

 

[Little Bill]

Is the load neutral connected to the GFCI or directly to the neutral bar in the panel?

I didn't have the timer when I posted my OP and thought since the timer was 240V clock motor and 240V line/load that there was no place for a neutral. I now have the timer and the clock motor can actually run on 277V. There is a terminal "A" that is for the neutral. You just connect the supply neutral and neutral to the clock motor under that same terminal.
So I suppose I could land a neutral under "A" and run it to the GFCI neutral.

I guess it wouldn't make a difference whether I used the terminal or not as long as I supply the neutral from the GFCI. I was originally thinking if I ran a neutral from the neutral bar and one of the 120V legs was used it wouldn't allow the GFCI to work.
I wasn't even thinking about using the GFCI neutral since I wasn't running a neutral to the timer.

But it seems it should work as long as I go through the GFCI with the neutral?

 

[jstjohnz]

Yes. Even though the loads on the 2 120V legs will be unbalanced by the 120V load that won't trip the GFCI.

 

[DrSparks]

The GFCI just wants to see the same current pulled from each leg returned on the neutral conductor with acceptable tolerance.