Hot Tub, GFCI, shared Neutral

[John120/240]

Cutler Hammer Classic disconnect with two pole 30 A, & single pole 20 A, both GFCI breakers with neutral pigtails to neutral bus. THHN/THWN stranded: # 10 hots, # 10 neutral, # 8 ground, # 12 hot & # 12 neutral to the tub location. Tub installer did the final hookup. Only the # 10 neutral was used by the tub installer.

How can both GFCI protected loads share the # 10 neutral ? Thank You

 

[ActionDave]

.... both GFCI breakers with neutral pigtails to neutral bus....

Where are the neutrals that go to the hot tub landed?

 

[GoldDigger]

Cutler Hammer Classic disconnect with two pole 30 A, & single pole 20 A, both GFCI breakers with neutral pigtails to neutral bus. THHN/THWN stranded: # 10 hots, # 10 neutral, # 8 ground, # 12 hot & # 12 neutral to the tub location. Tub installer did the final hookup. Only the # 10 neutral was used by the tub installer.

How can both GFCI protected loads share the # 10 neutral ? Thank You

They cannot in general. The current originating from one pole of a GFCI breaker must either return to that same GFCI breaker on the other pole or on the neutral for that breaker or some combination.

If there is no neutral current (not even 6ma!) then the neutral is not necessary for balance in the GFCI current transformer.

If two different GFCI breakers are sharing a common neutral return and that return goes only to the one breaker that has a line to neutral load, then you might get away with it. Until someone changes the load in any way....

 

[mopowr steve]

Just hooked up one of these hot tubs yesterday and it must be just like your's. I believe that the 30A circuit is the one that runs pumps and controller which utilizes a neutral while the 20A circuit was for the heating element which is 240 v only.

 

[Dennis Alwon]

I am confused by your statement. What size wire feeds the tub itself. I have never seen a hot tub that required 2 branch circuits installed by the electrician. I have always run 1 circuit to the tub and the tub then had a disconnect that was part of the tub manufacturing. Is this one different?

 

[mopowr steve]

#10 black,red,white,green and #12 blue,red. Yea it's a weird bird can't remember the name I think it said Cambria but anyhow it did require 2 separate GFI circuits from a Cutler Hammer disconnect which came with the Hot Tub. Although different configurations of various models either would only require the 50 amp with jumpers factory installed on the wiring block of circuit/control board or have separate GFI circuits, actually a 3rd schematic for a model required 3 GFI circuits 1-30A,2-20A. Bet that would find the tickle spot!

 

[mopowr steve]

You know what I just re-read the OP didn't catch the single pole breaker so now I'm confused as to what that electrician did on that Tub. Can't be right though.

 

[edlee]

When I've seen tubs with that sort of configuration the 2-pole 30 was for the heater, no neutral needed, and the other breaker was for pump and controls. Where is the #10 white tied in at the subpanel: to the 20 or 30.


Sounds like the electrician ran an extra white conductor out to the tub that is not needed.

Lee