Ground Fault Protection

[TopHattandTails]

1980 53MY. Hopefully this has been addressed (gotta be common). Out of no where (the boat is still on the hard inside heated storage), the Ships Service 2 panel, ground fault protector (white breaker) and main circuit breaker are tripping when plugged into shoreline #1 (no load). This has been set up like this and running the battery charger for the past 6 months with no issue. I flipped the external cordset into shoreline #2, reset the main panel to accept that power and all is fine on Ships Service #3 with Shoreline #2 (running only the battery charger). Appears that Shoreline #1 is causing the main breaker and ground fault to trip. All buss fuses at the cordset connection (outside) are verified to be in tact. Any known gremlins that might cause this? BTW - no new service or repairs...

[bostonhatteras]

corrosion perhaps breakers do go bad periodically

[DCMY #92]

Check the shore power cord plug and receptacle (both ends) for melting, corrosion, etc.

[SKYCHENEY]

Does it do it when you plug into the other side of the boat? Also, source 1 and source 2 are fed off of different isolation transformers.

[rwetherington]

try this. turn off all the breakers in the panel that is giving you problems. if the gfci breaker still tripps you more than likely have a bad breaker. the breaker is not avaibly any more. if it does not trip then turn on one breaker at a time to see which one does tripp the breaker or it may take two do get the fault high enough to trip the breaker. if it is a bad breaker you can call me and I will walk you through replacing the breaker with a new system.

[TopHattandTails]

thanks all. gotta do some checking... all breakers are off on the individual ships services for the AC panels. The main panel is what is tripping. I will try the other side of the boat's connections (outside).

Thought - Any way to test if its the isolation transformer or the breaker at the main panel (other than flipping main breakers out)?

Incidentally - the only breaker on in the boat is the bat charger (which works fine on the other leg) - no Ship service panel 3 (a/c units), no DC at all - just the batt charger (which I turned off to see if I could get the main to hold).

Roger - next time I'm at the boat, I'll give a call. thanks!

[TopHattandTails]

As suspected by Roger W., it's a bad ground fault breaker (Airpac 1002-2). No longer available. Got it rigged at the moment to work. I'll be calling some leads to see if it can be rebuilt. Other "fix" is to bypass the gfi at the panel and install somewhere else a new gfi. Thanks Roger for your help last Friday!

[REBrueckner]

How does a GFCI tripping cause a main electric panel circuit breaker to trip? (per original trouble statement?) Is that a design flaw of the older Airpac GFCI??

[TopHattandTails]

This is an OEM setup. Works pretty well. Not being an electrician...the GFI is a single pole (single flip switch) that measures the negative and the ground. When either is out of whack (the technical term) it "blasts" the ground of the main 4-pole breaker, tripping it. My understanding is that its basically a tube of brushes, that when they either heat up or expand, it makes contact with the center wire and trips the main. Since the main is GFI protected, the branch (ships Service 1, 2, or 3) is then protected, which then protects each individual circuit and then each individual device.

I talked to Airpac today and they quite making that GFI about 20 years ago and finally sold out of existing stock 15 years ago. Wards Marine Electric in Lauderdale can rebuild it, but wants "legal" policies in order to do so (of like Kinko's asking for written permission to copy your 1980 Detroit field guide -not sure copyrights expire or if they have a life period...).

Anyway - still need to get it rebuilt - 'cause I know its only a matter of time before the other main GFI bites it (that's the way it works, right?). Its not a problem on A/C's, refrigerators, etc., but on lights and plugs (really only plugs), it could be hair raising...

One option to fix might be to install a home GFI plug device in each outlet on the boat. This might work since the whole boat would not go dark, just the device, wich could be reset at the device. Quesiotn - does this pose a threat to the rest of the system? Maybe another solution would be to install one in a junction box in the genny room as the power comes out of the transformer (before the main panel). That way, the main is still protected and it can be reset (maybe a more accessible area in the dark would be good, like the ER with 32VDC available).

The best would be to get the OEM rebuilt so we don't loose OEM points... (preferred).

[Fanfare]

My boat was built before GFIs were invented, so I don't have to worry about OEM. I have installed new, modern GFIs in all head and galley outlets and they seem to work fine. One does trip about every three weeks or so, but immediately can be reset. Perhaps it is getting weak. As these have worked out so well I believe I will consider a few more, in the less critical areas of the boat. The good thing about these new units is that one will protect all the rest of the circuit passing downstream through that GFI. As I look at my wiring diagram it seems that about five GFIs should protect all the original electrical plugs on the boat. For example one would protect both aft heads although each has its own GFI now. This does keep my insurance underwriter happy.