I am not sure if this is a dumb question or not. We are getting a spa for our deck and the information provided to us by the manufacturer shows the electrical layout from the distribution panel to a subpanel with GFCI breaker and then to the spa. What I cannot understand is that there is a white (N) from the distribution panel to the subpanel connected to the GFCI breaker. But from the subpanel to the spa, only a black, red and ground. How does the GFCI breaker work if there is no neutral connected to the spa? Doesn’t the GFCI monitor current flow to and from the spa and trips when these values are not equal and doesn’t it need to the neutral to work properly? Thanks for any help.
Discussion Forum
Discussion Forum
Up Next
Video Shorts
Featured Story
Listeners write in about haunted pipes and building-science tomes, and they ask questions about roof venting and roof leaks.
Featured Video
Highlights
"I have learned so much thanks to the searchable articles on the FHB website. I can confidently say that I expect to be a life-long subscriber." - M.K.
Replies
First...I am not an electrician, but...
As I understand it the spa is running on 240 volts. To get the 240 you are actually using two 120 volt sources that are out of phase. The difference between any two of these is the voltage you see when you hook up to them. This phase difference gives you 240 volts. Hence, the neutral isn't used for the flow, it is the red and black that supply the 240.
If in doubt get a good electrician.
The GFCI monitors the current through all 3, 2 hots and neutral. If there is currents don't balance, within 5 ma, then it tripes.
Apparently your spa is a 240 volt only load, so it does not need the neutral and they did not need to run the neutral from the main pannel. But it was done because some equipement does use both 120 and 240.
For a 240 volt only load then it is comparing the difference between the 2 hots. For 120/240 load it is comparing the difference between the 2 hots and then that difference to what is in the neutral.