GFCI Breakers

[tjar]

Had a survey done on a 1993 Hunter 35.5 I'm planning to buy. No major discrepancies were discovered, but an electrical issue has me and the surveyor stumped.
All 120v outlets tested OK with the little three prong tester, but the GFCI failed to trip with the tester. We then tried all of the outlets and none of them would trip wither either the tester or by pressing the test button on the outlet.
Otherwise, polarity and everything else tests OK.
I found one article online that described a similar problem when upgrading old 2-pole house wiring to a three prong grounded outlet and somebody cross jumpered the hot lead to both the neutral and ground. But, we couldn't figure out how or why that could happen on a boat that originally had three wire AC.

 

[IStream]

I think you've just got a bad GFCI.

 

[tjar]

Normally, that's what I would think too. But, there are three GFCI outlets, all with the same issue. The probability of all three failing independently seems pretty remote unless something in the circuit caused them to fail.

 

[Johnb]

Testers work by diverting some current to ground to trip the GFCI. If the ground is missing that doesn't happen and the GFCI won't trip.

Or you have a bad tester.

 

[IStream]

Normally, that's what I would think too. But, there are three GFCI outlets, all with the same issue. The probability of all three failing independently seems pretty remote unless something in the circuit caused them to fail.

Sorry, I didn't get that from your original post. As the other poster mentioned, you could have a bad ground but I'm assuming your AC tester didn't flag that.

FWIW, I bought a well-maintained 1993 Catalina a couple of years ago and went through the AC system when I first got the boat. I found corroded connections, warm outlets (with nothing plugged in), and bad GFCIs. In the end, I'd still suspect bad GFCIs. There's a reason the newer ones have status LEDs, they're just not that reliable. On top of that, it's a boat. It's been sitting in water since 1993. The three GFCIs didn't necessarily go bad at the same time.

No matter what the cause, AC problems tend to be some of the easier/cheaper things to fix on a boat in part because the components aren't generally "marine grade" so you don't get screwed quite as bad on the parts. This also means that they don't necessarily age well in a marine environment, especially if it was wired like a house with push-in connections at the outlets or (God forbid) wire nuts. I wouldn't let it scare me away from a purchase. If you're handy with AC, you can go through the whole boat in a day and replace all the outlets with new and replace all the terminals with rings for $100 in parts. If you're not comfortable with it, budget $1500 for an electrician to do it for you.

 

[SEMPERAVANTI41]

With a VOM, I would check the voltage from the hot terminal to the ground terminal of the GFCi in question. You should see line voltage, around 120 volts the same as a test from the hot terminal to the neutral terminal of the GFCI. This will indicate whether the problem is the ground or the GFCI.
If it were me, I would change the GFCI to new ones as they are only around $10.00 at HD.

 

[tjar]

Thanks for the input. I'm not letting this little issue scare me away. I have no problem jumping in and tracing down the problem. It's just one of a small number of items that my surveyor found. Otherwise, it's in very good condition and just needs a good scrubbing.

 

[sailortype]

I am a home inspector, you would be amazed at how many GFCI breakers I find that will not trip when tested... possibly 25% or more. If you read the fine print on the instruction/installation sheet, they should be tested monthly and few people ever test them. Then they freeze up and will not work... power but no protection.
I am assuming you have three separate circuits with GFI's on each..? You only need one per circuit... redundant GFI's on a single circuit can cause problems and confusion resetting, only one needed on the first receptacle in the circuit. Remove the others and replace with standard receptacles.
It does sound like you have faulty GFI's... replace one and see how that goes.

 

[tjar]

As soon as I take possession of the boat, this will be one of my priority fix items. I will first have to trace the wiring to figure out if they are on three separate circuits, or wired in series on a single circuit. If in series, then I will remove the other two GFCI outlets.
I would not be surprised if they are all bad due to age. The boat has not had any serious maintenance in several years.