Original > Hot Tub Forum
GFI Tripping
Jacuzzi Jim:
Either would work, if it were me I would just order the whole tube and slap it in. But not from that site. You should be able to find the same thing for less. 120 to 170 range.
Botswana:
Ok I found it for 150. Right now, I was able to set up that camera and the cloud storage so I can see videos of the LEDs. If the tub is tripping during or right after heat cycle I'd be able to tell since a red LED comes on when it heats. If it trips without a red light on I would doubt it's the heater. Regardless, gonna wait to order heater till next trip or two when I can review the video evidence.
bud16415:
Sounds like you have a workable trouble shooting plan with the camera. Give that a go and see what you find out.
As to the megger test you are actually testing the insulation between the heater and the metal that contains the water and eventually your earth ground. The way the insulation gets tested is by forcing a voltage on it as great or greater than it normally sees. Wire for 240v insulation is rated at 600v so there should be a safety factor. So in the case of wire shorting out you would test it with some voltage lower than 600v. you don’t want to make the item fail with the test unless it is below spec.
So say your heater normally sees 240v and is insulated for 600v as the safety factor but is breaking down slowly from water weeping or corrosion. Now it works fine at 240v but might fail at 250v. So maybe a little voltage spike will trip it once in a while. The megger test will find something that is boarderline.
Be careful with holding the probes or clamp, you want to stand back and push the button as these things will give you a good jolt. In the old days you cranked them now they have batteries and step the voltage up.
Botswana:
Bud -
I understand the concept of a megger, I just don't necessarily know the actual steps in conducting the test. I would disconnect both power leads from the heater to the board and put a probe in one of them. The other line from the megger would go to the grounding bar on the heater, where the 2 pumps are also grounded, correct? The heater ground itself is screwed into the main spa board. I'm guessing so that the heater and board are tied together which is then grounded by the green wire coming out of the breaker. Are those the correct steps? Also to make sure megger is on 500v..
For pumps i would disconnect both conductors from the main board, probe one, then put the other line from the megger onto the heater ground bar where the pump ground is connected, correct?
I'm fairly confident my neighbor did it correctly, I also just want to learn and there's no harm in testing twice.
bud16415:
Personally I would totally isolate the device I’m testing electrically. No need to remove it from the tub. Chances are leaving the ground connected won’t harm anything as the ground should all be common and go back to earth. I just wouldn’t want 500v anyplace on the controller if I didn’t have to. Think of it as if you were trying to burn out the heater by forcing it to arc to the casing. In this case you shouldn’t put enough voltage to do that unless it is already a bad insulation. It should be good for at least 600 volts. I don’t know the exact spec the heater manufacture would test at most likely 1000v or something like that. I would feel safe testing at 500v.
You could do the same thing disconnecting the power wires on both end and megger testing between the two wires and ground. If you had a slight breakdown in the wires it would show up. That would be something like a nick or crack in the wire insulation that wouldn’t pass current normally but if they got wet then it could trip the GFCI. Remember a GFCI only needs to see I think 5ma going to ground to trip and the trip happens in one cycle of the power so it shuts you down before any melt thru could take place.
The megger does not have the current potential like the main feed has it is mostly just
Voltage. Kind of like the spark plug on your lawn mower. It is not likely to kill you but it can give quite a jolt.
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