Hot Tub GFI

[Trevor Sams]

I have a hot tub connected to a 50 amp 220v trip that has a neutral pigtail connected to the neutral bus. The natural for the tub is connected to the bus. The 220v connects directly to the control panel PCB which then has a series of relays to switch the pumps, water heater etc. The GFI started tripping. The individual connectors were all separated from the PCB for the 220v connections such that the only thing that was being powered was the control board running 110v. It still tripped the GFI immediately. The operation of the GFI felt a bit odd and the ‘on’ position did not feel as though it went home when the power was off. So I replaced the GFI with the same result, an instant trip. I then removed the secondary winding's (12v & 24v) from the PCB. Same result. I then removed the ground from the transformer, same result. I then removed the primary coil from power and no trip. I replaced the transformer. When the new transformer is connected I get the exact same problem, instant trip when powered. I then disconnected the hot tub completely at the breaker box. I then wired the new transformer directly to the new GFI and it trips immediately with no load connected to the secondary. I tried it by removing the ground from the transformer no change. What am I doing wrong, or is the new transform faulty as well? I just followed the original wiring. When the GFI is bypassed the tub works as normal. NO I would not use the tub with no GFI! Help!

 

[hj]

Is the 110/120 neutral going through the GFI? It appears that it is only monitoring the 220/240v system, so the panel's neutral is giving a "fault' indication.

 

[Sponsor]

 

[Jadnashua]

A GFCI monitors power-in/power-out. On a pure 120vac or 240vac circuit, it only needs to monitor two wires (ground is a safety, and is generally connected as well). On a device that uses both 120 and 240vac (because the thing uses some 240 powered things and 120vac power things), to determine if everything is working properly, it needs to monitor L1, L2, and neutral. If your GFCI only is looking at L1 and L2, since some of the power going out on one lead will be coming back on the neutral, L1-L2 won't be balanced, and it will (or should) trip.

 

[WorthFlorida]

Trevor didn't mention it but more likely this tub has been installed for years and now the GFCI trips. Because of some words I assume it was typed from a Iphone or Ipad. Trying to find information on 220v GFCI's, I found this video. The intro is goofy but has good info. At the 3:00 minute mark explains the most common error, but it is usually for new installations.

 

[Trevor Sams]

Thanks for your reply. Being British I am used to a 240v single hot at 50Hz. I made the mistake of following the original wiring verbatim without referring to the instructions! The reason why the original GFI did not work was as you correctly say it was wired to the neutral bus not the neutral on the GFI. I guess the lesson here is don't assume!

 

[Jadnashua]

A GFCI is supposed to trip if there's a difference in power-in and power-out of >5ma...I'm sure your 120vac circuits in the tub use more than that, so L1 won't equal L2.