Shore power breakers

[moonshadow]

Hi. My 2014 SO469 has a bank of 4 circuit breaker boxes. One each for shore power-house. And one for HVAC shore power. These are repeated for the generator side. Each box also has a bigger breaker (GFCI I believe) marked FPEAU and a thinner MPC452. The original GE MPC452 breakers seem to go bad after a few years. These are not made any more and I am trying to find a replacement for at least one. And a spare.
Does anyone here know where I could find some in the U.S.? I tried looking up the current model to replace these and no luck yet. I don’t know if these are a standard item. Any help appreciated.
Thanks, Paul

[Trevor]

Hi moonshadow,

The breakers used I think will be pretty standard and will probably fit onto a standard DIN rail mounting. The thin one is probably one DIN unit wide (18mm) and will have a current rating marked on it. Just purchase one that will physically fit with the same current rating.

The GFCI is a slightly different beast and is designed to trip when the current and the active and neutral conductors are imbalanced. If a imbalance does occur it means some of the current is going somewhere else. it means some ground current is flowing so the the GFCI releases until the leakage current fault is foxed.

Once again, they very standard, usually with a maximum imbalance of 30mA allowed. That is the maximum trip current but they can trip at 50% of that figure (15mA) and be within spec. Typically they trip at about 20mA.

Regards,

Trevor

[moonshadow]

Well.. so far I have spent a few weeks looking for these breakers. Cannot find two pole breakers in the 13mm width. It turns out that GE sold this product line to a company called “APP” they do show some similar but not quite exact breakers. Most recently I spoke to the APP tech support people and sent photos, part numbers etc from the old GE parts. They said they should get back to me within. Day with current product suggestions. That was a week ago.
Anyway, since I’m out on a trip now for a few months and I have some guests flying in soon, I ordered some two pole breakers that will not fit in to boxes and some din mounting rail. There seems to be enough space nearby to just add the din mount and the breakers and make up cables between.
I have been told by a number of people that these skinny din mount breakers are commonly available. If anyone has a source I would be grateful to have that info.

[Trevor]

Hi moonshadow,

If they are 13mm width that is very narrow. The standard one unit DIN width is 18mm normally. Good luck with the modification. It is a shame the existing ones are non standard.

Trevor

[moonshadow]

Thanks again Trevor. Yes it is a shame that these are no longer available. I suspect that the high failure rate might have something to do with the lack of availability. My wider breakers and some DIN rail to mount them should arrive in a few weeks and I’m looking forward to seeing how well the modification works.

[moonshadow]

A few updates for anyone following this. I hope I can help someone else avoid similar concerns.
First off, the breakers in question are 18mm not 13 as for some reason I had in my mind. Sorry about that.
And, these breakers:32 amp, one pole plus N, 18mm are easily available in Europe. I have someone hunting some down for me in England.
Now, some things I have learned that are applicable to many of our boats. Remember that I am learning and I don’t consider myself a final definitive source. Feel free to double check and correct me. These breakers are designed as “supplemental Breakers” for branches off a main circuit, usually for individual equipment. Not usually for a whole main circuit. Being certified as supplemental they only need to trip once in testing and are not required to be resettable many times. This might explain why they “fail” so often. The general rule of thumb is that any circuit should be designed for 80% only of the rated load. And with a 30 amp input with 32amp breakers this would mean normal load limits of 24amps. My boat, like most delivered to US has 3 aircon/heating units. Each draw about 10 amps. Plus whatever inrush current surge there is during compressor start up. So by design these circuits appear to be inadequate for the boat. Now I won’t run all three at the same time.
And, since diesel engines like to be run with a load on I always tried to keep an electrical load when I run the generator. Battery charger, water heater, Watermaker, charge up my devices etc. Again it seems good for the generator but not for the electrical system.
Which all leads me to believe that I need to do more load management. I wasn’t previously aware of the need to watch my loads, believing that the boat electrical system was designed for what was installed on the boat. So now I limit my electrical load when I use generator or shore power and time will tell if this is all true. I hope that what I have learned helps me and is useful to others. And of course I will keep spare breakers on the boat when I obtain some.