Installing a new hot tub with no neutral, will this breaker work?

LyndMc said:
I’m swapping out an existing hot tub with a new one that has no neutral. Anyone familiar with this ABB breaker that confirm that it will work with no neutral on the load side?

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It will work. The neutral tail on the breaker needs to be connected to the neutral bar in the panel, to provide 120V to the breaker electronics. If there is a neutral load, it must be connected to the breaker, and that load is connected back to neutral via the pigtail. If the new hot tub doesn't need a neutral, you don't have to connect to the neutral LOAD terminal on the breaker. The breaker will still sense any ground faults from either line to ground just fine.


SceneryDriver
 
I just realized that my wire may now not be sufficient. The old tub had a 40a breaker and was wired with 10 gauge. I’m thinking I’m now going to have to change the entire cable to 6 or 8 gauge! This will be a major undertaking since the cable was put in before the ground level deck was built.
 
SceneryDriver said:
It will work. The neutral tail on the breaker needs to be connected to the neutral bar in the panel, to provide 120V to the breaker electronics. If there is a neutral load, it must be connected to the breaker, and that load is connected back to neutral via the pigtail. If the new hot tub doesn't need a neutral, you don't have to connect to the neutral LOAD terminal on the breaker. The breaker will still sense any ground faults from either line to ground just fine.


SceneryDriver
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To be clear, the PANEL that it goes into must have a neutral, because the electronics inside of the breaker requires it. But if the LOAD that it connects to does not need a neutral internally, i.e. all of the loads are straight 240V, then you do not need a neutral wire going to the load.
 
Jraef said:
To be clear, the PANEL that it goes into must have a neutral, because the electronics inside of the breaker requires it. But if the LOAD that it connects to does not need a neutral internally, i.e. all of the loads are straight 240V, then you do not need a neutral wire going to the load.
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I kind of assumed that the panel the breaker is installed in has a neutral, but you have a good point. If it's a spa panel, and the last electrician didn't pull a neutral, it wouldn't work.


SceneryDriver
 
Jraef said:
To be clear, the PANEL that it goes into must have a neutral, because the electronics inside of the breaker requires it. But if the LOAD that it connects to does not need a neutral internally, i.e. all of the loads are straight 240V, then you do not need a neutral wire going to the load.
Click to expand...
Yeah I always thought that was a not the best design choice by the manufacturers, if they simply powered 240V GFCI breakers internal electronics off the 240V L-L they could be used in more applications, like single phase 240 GFCI circuit off a 240 delta service.
We had a epic thread quite a few years back ~2019 with a fella from the Philippines where they follow a modified version of the NEC, but they have straight '240' volt services in rural areas and 120/240 in cities. 120V is no longer used for appliances there, so if a service is 120/240 all the breakers are 2-pole.
He posted some pics of the residential GE panels the ones in the 240V rural area (2 wire with no 120) had these funny little control transformers in them, they used them to power the electronics of GFCI breakers.
One would think a 'neutral' ground reference would be needed to detect a ground fault, but presumably it is just measuring imbalance on the lines.
 
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