Circuit Breaker Surprise

[Juliet 15]

Hi all! We have a 58 LRC from 1975 that has thrown us for a loop. :^/

1. Yesterday all the AC power dropped off. I checked the big AS panel at the helm and discovered the bottom right "Hatteras 120VAC Lines B and C" breaker had flipped.
2. This is a big black 4-pole breaker sitting next to 2 white breakers.
3. The white breakers are marked "FAULT" and "OVERVOLTAGE" respectively.
4. After much investigation (read: 8 hrs of laborious troubleshooting) I've determined that the white "FAULT" breaker is tripping first, causing the black 4-pole breaker to follow suit.
5. I disassembled ad examined all of the bow and stern shore power hookups - all is in order; no shorting, no burn marks, no loose wires.
6. I opened up the big AC panel and examined the back side - all is well, nothing shorting, no burn marks, no out of place wires.
7. I shut off all other AC circuit breakers in the entire boat to isolate individual systems. No change.
6. I used shore power - no change. As soon as power is applied, the white breaker trips followed instantly by the black 4-pole Lines B and C breaker.
7. I tried going off generator power - no change.
8. I tried swapping a different white "FAULT" breaker from another part of the panel. No change!
9 (Here's where it gets interesting) I decided to try leaving the "FAULT" breaker disconnected.
a. I disconnected the "IN" wire to the white breaker.
b. I flipped the black 4-pole breaker back on.
c. I started the genset - and everything worked!!
d. I shut id own and connected to shore power - and it worked.
10. As long as I leave the white beaker disconnected all the AC system work normally.

I left it on for long enough to charge the batteries, then shut it off. Anyone have ideas as to what is wrong or where to begin looking? Similar experiences?

Thanks for any insight!

 

[Cricket]

Think my first try would be to find/purchase and install a new fault breaker.
Breakers do go bad and also GFCI outlets, hopefully it's as simple as that.

 

[Juliet 15]

Yeah, I thot so too, but I swapped circuit breakers and the problem stayed with the location. It didn't move. Can't be the breaker.

 

[SEVEN]

All the breakers are old they may be weak. Install a brand new one hopefully that will resolve your issues.

 

[Boatsb]

I've been using the new elci breakers on upgrades. 50 amps in a package that has reversed polarity indicators , power lights and all the necessary safety features. I'd put that at the inlet (no more fuses to deal with) and then all you need at the main panel is the legs and neutrals.

 

[sixty]

I've been using the new elci breakers on upgrades. 50 amps in a package that has reversed polarity indicators , power lights and all the necessary safety features. I'd put that at the inlet (no more fuses to deal with) and then all you need at the main panel is the legs and neutrals.

Do you have a specific part number you use? I would love to ditch my fuses.

 

[Boatsb]

I'll PM a number. Call me tomorrow. It's not just a part number. The box (weatherized) and glands need to be added too.

 

[oscarvan]

He said swapping in another one made no difference anf the problem staid with the location... ie the thing may actually be doing its job.

Time to get a multi meter on there to see if you may actually have a ground fault. Happy hunting, these things can be a pain.

 

[riverrandy]

I had this exact issue some months ago. After talking with many, I finally spoke with Hatteras (got number and name from SAMS). the Electrician who wired my boat in 1975 explained how compressors cause an extremely brief GF. As the GFCI breakers get old, they will trip more quickly. Has went on to say if I had GFCI outlets at all the "wet Location" like ABYC requires, then that old (now obsolete) white fault breaker needs to be disconnected. I cut the white wire and have had no more issues. You have done the correct repair.

 

[Juliet 15]

Randy, that's amazing you were able to talk to the electrician who wired your boat. I'd love to get that number from you.

UPDATE: I spent this entire weekend working it and i finally got it down to, "any time the 240vac service #1 is hot, the 120vac service B and C fault breaker pops". Then, in an attempt to discern if the problem was upstream or down stream of the fault breaker, I disconnected all 4 wires from the bottom side of the fault breaker block. The problem went away. I reconnected all the wires, and the problem is gone. I can't explain it; all I know is I can no longer replicate the problem. It doesn't exactly give me a lot of confidence.

Also, the PO removed all air conditioning from the boat, so the only compressors are the air compressors I have for the toilet system (1) and the air horn (1).

I had all breakers and systems switched off during the troubleshooting to eliminate them. The breaker kept popping, indicating to me it's a power source problem. I hate to go with it as is - I can see the accident report now: Captain disabled his short protection and boat burn at sea...

 

[zigzag930]

Juliet: Any further updates on this issue?

I ask because this weekend I opened up the "selector" panel to look for some abandoned inverter wires. Much to my surprise I found a black wire running from pole one on my 4 pole breaker to the "trip" breakers where all removed and taped together to another black wire on both 120V banks.

One of these pairs was loose and when I moved it, I heard a clicking sound from behind the electrical box (which I did not locate). Anyway, I thought this might be a safety issue and hooked them back up to investigate. NO issues found yet and my "test" button now properly causes the breakers to trip, where they didn't previously.

I have a 77 58LRC, so hope to hear from anyone that has any insight regarding this issue.

J