GFCI Trips on New Hot Tub

I bought a Twilight Series 8.25 hot tub. Installed 4 days ago. I installed a new 50a breaker in the main breaker box. This is connected via 4 wires (2 hot, 1 neutral, 1 ground; all AWG #6) to an outdoor Square D 50a weather proof GFCI breaker box. This is then wired via PVC outdoor conduit to the hot tub. I finished the wiring yesterday and turned the hot tub on and everything fired up no problem. The heater worked, all jets worked, etc. After about 10 hours, the water had gone from 64 degrees to 96 degrees. It rained last night also. When I woke up this morning the water was hot but the GFCI had tripped. I tried to turn it off and on and got nothing - it trips immediately. I checked the breaker box and and conduit and the panel on the hot tub for leaks and found no evidence the rain had gotten into my wiring as nothing was wet. I took all the wiring off and reconnected all circuits to no luck. I disconnected the wiring from the hot tub and the GFCI does not trip and my multimeter shows sufficient current. I tried un-plugging the individual components in the hot tub - pumps, heater, ozone and it still trips.

I am lost. I assume I have a ground fault and current leak somewhere but cannot figure this out. I found no instructions that I need to use a grounding rod from the outdoor GFCI breaker box but could this be it? I can't understand why it would work for 10+ hours and then just quit. I also called the hot tub delivery people to come out and look as I do not want to try to fix a brand new hot tub so I hope it is my wiring.

Thanks in advance.

 

Welcome to the forums.

Your supply wiring sounds correct. When you disconnect it at the tub and the ground fault disappears tells you that the problem is in the tub. A ground rod is not needed at the tub and would not be the cause of the GFI tripping.

When I troubleshoot a spa/tub, I use an ohmmeter between the ground and one hot wire at a time to look for the leakage.

 

Thanks for the reply and welcome!

Okay so I hooked up the voltage meter. Black and red hots yield 220v. Red or black to neutral yield 110v and red or black to green yields 110v also. When I switch to Ohms X1K or X10, black or red to ground trips the breaker. So I guess I have a leak on the ground wire? I'm going to pull it out of the conduit and check for damage to the casing. Short of that (so to speak), any other ideas based on this information?

 

To note - I tried the same thing at the GFCI breaker box before pulling the ground cable out to check for damage. When I try it at the breaker box - black to ground or red to ground on Ohms, it trips the circuit. I go back to wondering now if the breaker box needs a grounding rod? Thoughts?

 

First things first...... when using the meter in resistance mode (OHMS) the circuit must be dead.
Connecting a meter set for ohms to live wires will usually cause a small explosion inside the meter.

To check for leakage. Turn off the main breaker feeding the tub.
Remove all 4 power wires from the tub.

Connect the black lead of the ohmmeter to the ground terminal or a metal part of the tub.
Connect the red lead to one of the 240vac terminals. You should see no resistance. No resistance means that when the lead is connected the meter reading doesn't change.

Now try the same thing to the other 240vac terminal. Again, no reading should be seen.
Now try the same thing to the white/neutral terminal. Again, no reading should be seen.

 

Good point...just blew the fuse on the analog multimeter. I shut off the main breaker and disconnected the wires from the spa. Both hot leads with the ground read zero. Ground with neutral fluctuates though and shows a reading. I assume this means that cable is not set properly? My neutral goes from the main breaker to the neutral bar on the GFCI breaker box. The white pig tail from the breaker is connected to the same neutral bar and the white neutral out goes from the breaker to the hot tub. This means that last connection or wire somewhere between the GFCI breaker and the hot tub is bad?

 

At this point we're only interested in the tub. If the wires are not connected to the tub then the wiring is not the problem.

I had meant to write before that your meter should be on a high scale like Rx10 or Rx100.

Sol you are seeing a resistance between white and ground. That could cause the GFI trip and shows leakage. Can you tell me what the resistance actually is ?

 

Thanks PJ. So, I thought you were saying to check the resistance on my wiring. I went back and checked the terminals red and black and neutral to ground. No resistance as you said. I checked my wires and red and black to ground yielded 0 but the white to ground on the wires itself, both where is connects to the tub and the breaker read fluctuations between 3 Ohms and 50Ohms constantly bouncing around. I don't believe that is normal. So now I'm back to thinking the tub is okay and I have a short in the neutral wire somewhere.

 

You can't check the wiring if it's connected to the GFI breaker.

So at the tub..... You didn't measure ANY resistance between any terminal and ground.
That would indicate the tub is ok.

 

Right - and that's a huge relief. However, I still have the problem of the GFCI tripping when everything is plugged in. I still can't figure that out...

 

Did you try disconnecting the wiring at the GFI and the tub and testing again ?

Somewhere.... you have a leak to ground. Set your meter on it's highest ohm setting.... Rx100 or higher.

 

Okay so I disconnected the wires from the GFCI and the hot tub. I tested the Ohms from the red, black and neutral to ground individually and all registered zero. So no luck finding the leak.

I did some more research and I may have the issue. The GFCI will trip if the voltage on the hot out doesn't match the neutral back and my neutral wire wasn't long enough from the breaker box to the hot tub so I used a tie to connect a patch wire and covered it in electrical tape. I know this was done right and it reads the right voltage when it is plugged in but I imagine this could affect the voltage on the neutral return and trip the breaker. I am going to replace that wire with a full length wire and see if that works.