Hot Tub GFCI troubleshooting

[Megawatt]

Thanks for the reply. If the 12v lighting supply was not suitably isolated from the mains, would that be an issue with the hot tub's control board design? Or is that something that would happen on a single tub's installation? Could you describe this a bit more if possible? Thanks!

All I can tell you is if that breaker was wired correctly it would have tripped the GFCI breaker. The hot tub internal wiring is correct but with the cover broke you done the right thing by taking those particular wires loose
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All I can tell you is if that breaker was wired correctly it would have tripped the GFCI breaker. The hot tub internal wiring is correct but with the cover broke you done the right thing by taking those particular wires loose

Just because you can push the test button and it trips don’t mean it’s wired correctly

 

[bmbouter]

All I can tell you is if that breaker was wired correctly it would have tripped the GFCI breaker.

I also suspect the wiring of the GFCI is incorrect, but here is some info if you can tell me what you think. The pictures don't make it very clear, but here's what I just confirmed (along with another not-so-great picture). The neutral from the hot-tub is not connected to the neutral breaker bar; it is connected to the GFCI at the terminal with the white dot. The GFCI pigtail is connected to the neutral breaker bar, along with the incoming neutral from the main breaker box. The hot-tub's two load lines are also connected to the GFCI directly also. The ground bar does connect the hot tub ground line and the main breaker circuit ground and nothing else. Based on my reading, this seems correct, but what do you all think?

 

[Megawatt]

I also suspect the wiring of the GFCI is incorrect, but here is some info if you can tell me what you think. The pictures don't make it very clear, but here's what I just confirmed (along with another not-so-great picture). The neutral from the hot-tub is not connected to the neutral breaker bar; it is connected to the GFCI at the terminal with the white dot. The GFCI pigtail is connected to the neutral breaker bar, along with the incoming neutral from the main breaker box. The hot-tub's two load lines are also connected to the GFCI directly also. The ground bar does connect the hot tub ground line and the main breaker circuit ground and nothing else. Based on my reading, this seems correct, but what do you all think?

In your pictures the neutral for the hot clearly hooks to the ground bar not the breaker. The squiggly wire should terminate on the neutral bar and the neutral for the hot tub hooks to the terminal on the breaker. It looks like that both the wires are attached to the bar in the extra panel with the GFCI which puts them both together and then your neutral goes to another panel and terminates on the neutral bar. They have to be separated. I see a spare double pole breaker in your main panel that is labeled spare, that should have been taken out and your GFCI breaker installed in its place

 

[westward10]

Surely the neutral is connected correctly at the GFCI or it would constantly trip but I agree the neutrals appear to be at the ground bar.

 

[Lucien Nunes]

It looks OK to me. The ground bar is bottom left, I see two wires. The neutral bar is top right. Cables coming in from the back go to the neutral bar and the top terminals of the GFCI. The cable going out at the bottom connects to the bottom terminals on the GFCI. And yes, if the neutral were going through in the wrong direction, any neutral current (i.e. any 120V loads) would immediately trip it.

 

[bmbouter]

Yes the photos do make it seem as if the hot tub side neutral is wired to be neutral breaker bar, but in examining it up close, it is not the case. Sorry to not have a better photo to demonstrate this with. I appreciate all the time and concern folks have put into helping confirm the wiring is correct.

 

[bmbouter]

The GFCI only protects, and only needs to protect, the AC line circuit and components connected to it that operate at 120/240V. The 12V lighting circuit is derived from a transformer or power supply unit; even if that obtains its power via the GFCI, its 12V secondary side should be independent and the current used at 12V does not pass through the GFCI, therefore, if an imbalance or leakage occurs, the GFCI will not detect it. A GFCI on this circuit is not considered necessary because at 12V, the maximum current that can pass through the water is very limited and not hazardous, although you can often feel it if you are in very good contact.

What you're saying makes sense, but I still want to learn more. In this case the GFCI circuit is the only power to the hot-tub control box, so the 12V lighting circuit's transformer does power it. How can AC current flowing into the light's transformer transfer power to it's secondary side without loosing any current? Feel free to refer me to something I should read also.

I'm still very concerned... I've been reading some about stray voltages here Mike Holt Enterprises - the leader in electrical training. - https://www.mikeholt.com/technical-stray-voltage-newsletter-menu.php and also here Stray Voltage - No You are not Crazy - https://www.mikeholt.com/mojonewsarchive/SV-HTML/HTML/StrayVoltageNotCrazy~20031020.htm The shock I felt was not small, I think if I had been in the tub when the light failed I would have died.

I don't know what to do because how can I be sure it's not caused by something like what is described in these articles. I'm concerned that even a good electrician could not solve such a strange problem. After verifying (as we have) that the wiring is good, and if the GFCI tests good what could they do to assure me that this is safe?

 

[marconi]

This is so important please could you post a better picture so those 'in the know' can confirm the wiring is actually correct for you.

 

[Megawatt]

What you're saying makes sense, but I still want to learn more. In this case the GFCI circuit is the only power to the hot-tub control box, so the 12V lighting circuit's transformer does power it. How can AC current flowing into the light's transformer transfer power to it's secondary side without loosing any current? Feel free to refer me to something I should read also.

I'm still very concerned... I've been reading some about stray voltages here Mike Holt Enterprises - the leader in electrical training. - https://www.mikeholt.com/technical-stray-voltage-newsletter-menu.php and also here Stray Voltage - No You are not Crazy - https://www.mikeholt.com/mojonewsarchive/SV-HTML/HTML/StrayVoltageNotCrazy~20031020.htm The shock I felt was not small, I think if I had been in the tub when the light failed I would have died.

I don't know what to do because how can I be sure it's not caused by something like what is described in these articles. I'm concerned that even a good electrician could not solve such a strange problem. After verifying (as we have) that the wiring is good, and if the GFCI tests good what could they do to assure me that this is safe?

bmbouter you would have piece of mind if you would call an electrician to rewire that breaker. I’ve seen enough pictures to know it’s wired wrong, and if it was me I would take that spare double pole breaker out and put that GFCI breaker in the main panel where it belongs. Then it would have tripped when the lens on the light broke. Good luck

 

[Lucien Nunes]

How can AC current flowing into the light's transformer transfer power to it's secondary side without loosing any current

In a conventional wirewound transformer, the 120V / 240V primary circuit energises a coil that creates a magnetic flux in the iron core. That magnetism then induces a current in a totally separate coil on the 12V secondary side. Because there is no electrical connection between primary and secondary, a faulty circuit or device connected to one side of the transformer can only create leakage on that side. The quality and strength of insulation between primary and secondary depends on application; a transformer made for safety isolation (e.g. between AC line and hot tub) will have insulation made to a recognised standard.

In an electronic power supply unit there is still a transformer, but by converting the incoming AC power electronically to a much higher frequency the transformer can be made smaller, lighter and more efficient. This frequency conversion can cause a small amount of leakage to pass across the transformer capacitively, from primary to secondary, but under normal conditions it is too small to cause harm and too small to trip a GFCI.