Having an electrical issue

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kimbo
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Posts: 16
Joined: Mon Oct 09, 2017 12:44 pm
Location: Michigan

Having an electrical issue

Post by kimbo »

Over the weekend my capac reading was at 0.6 instead of the usual 0.9. My refrigerator had quit working sometime during the previous week. The refrigerator breaker switch was off at the panel when I arrived this weekend. It was on when I left the previous weekend. When I push the refrigerator switch on, the panel Amp meter pegs right and shortly after the panel refrigerator switch turns off and the Amp meter pegs left. There is a buzzing sound for about 3 seconds when the fridge switch is turned on before it turns off by itself. The only way I am able to obtain 0.9 on my capac is by disconnecting shore power from the boat. Turning the AC circuit off at the panel makes no difference. I have moved and disconnected the fridge from any electrical connection. Is this just a bad fridge switch at the panel? My Marinette is a 39dc 1985. Any advice is appreciated
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GB49
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Joined: Sat Jul 12, 2014 8:23 pm
Location: Catawba Island, OH.

Re: Having an electrical issue

Post by GB49 »

Does the fridge work on the 12VDC system?.....Generally there are 3 switches for the fridge (assuming its the original Norcold).
1 on AC panel
1 on DC panel
1 front bottom of fridge

The breaker(s) will trip if a direct short to neutral/ground or extreme Amp draw such as seized equipment.

The buzzing may be coming from the galvanic isolator. Generally they will buzz if voltage is sensed on the ground leg.

Check all shore cord connections for melted/brown connections.

Almost sounds like a couple issues, fridge is "sick" and possible issue with shore power. After checking your power pedestal, check any neighboring power peds for melted cords.

I had a neighbor 2 docks down with a melted cord at the pedestal that caused my isolator to buzz.
1986 Sedan 32'. Twin Chrysler 360in^3, 275hp, with K&N flame arrestors.
Forum member since 1998, 1262 original forum posts.
barkleydave
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Joined: Sat Jul 12, 2014 6:18 am
Location: Kentucky

Re: Having an electrical issue

Post by barkleydave »

First off your CAPAC reading is NOT related to an AC issue. Readings will fluctuate with water temp, marine growth on Anodes and of Cathode.
Also loss of shaft isolation will drop you readings. AC leakage may effect readings. Remember CAPAC readings are NEGATIVE VALUES.

You you a serious ground fault! It is not uncommon for a refig to corrode resulting in a short to ground internally. Water Heaters are also common sources for ground fault.

1. Take refrig off line!
2. Inspect all AC electrical connections breakers etc for corrosion and poor connections.
3. Your galvanic isolator is buzzing because current bleeding into the circuit at a higher rate than it can handle. There is always some DC current on an AC line. The Isolator prevents DC current from running on your AC Neutral.

4. Battery chargers can also be cause of AC bleed especially if they are not approved for Marine Use. Automotive chargers are not well isolated.

I have a stray current tester that floats and will sound alarm if there is stray AC current. I use it several times a year around my boat and every season when I start our pool up.

I would also suggest that if you have not done this is to replace our AC outlets with GFCI outlets. Run your circuits in series so only one GFCI outlet will protect all outlets down stream.

This is a serious safety issue!
1987 Marinette 29 FB Sedan
Retired Boat Accident UL and USCG trained investigator
Retired USCG Captain
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