House Battery Circuit Breaker

K

kennharriet

Member
I recently added two AGM house batteries in addition to the start battery. The way I read the ABYC standards there should be a circuit breaker between the house batteries and the distribution system to protect that length of wire between the batteries and distribution system behind the helm. That is not the case from the factory. It says the capacity of the breaker should not exceed 150% of the maximum potential downstream load. Both the house and start batteries are connected with a Yardina combiner. My house distribution system is the factory fuse system behind the helm.

What type and size of circuit breaker should I use if one is required? It makes sense to me to use a switched breaker for quick disconnect in an emergency with manual reset.

I have the windless on the start battery on it’s on circuit breaker. Otherwise I have the typical house load of led lights, nav lights, anchor light, cell and iPad charging, vhf, chart plotter and the Wallas 1300 heater.

Thanks in advance. I admire all the experienced wisdom in the group.
 
The ABYC spec is within 7" of the battery, unless well supported such as in a wiring run or tray.

I use a 60 amp breaker for the 22 and 25 for the console wiring (and any other circuit except starting and windlass (use separate 40 to 60 amp breaker for this). While I am at it, I usually run a second line-at least 10 AGW wire--for the 25 8 AGW wire.
 
Thank you Bob. That’s what I needed. I have the factory 10 awg primary wire running from the battery to the helm fuse distribution panel. I have read some other conflicting info that a breaker should never be used but rather a fuse in this application. Any thoughts on that. Ken
 
kennharriet":2vffplqd said:
Thank you Bob. That’s what I needed. I have the factory 10 awg primary wire running from the battery to the helm fuse distribution panel. I have read some other conflicting info that a breaker should never be used but rather a fuse in this application. Any thoughts on that. Ken
Click to expand...

I have always used a circuit breaker in this circuit, and the C Dory factory has also.
 
Ken, I would concur with Bob and personally I would use a breaker in your application as well. My invertor/charger(Trace SW2512mc) was installed with a class T fuse(Edison TJN250) which I believe is a fast blow fuse and perhaps as much to protect the invertor as the wiring. Lucky I have not blown it too often as they are $50.00 to replace - much cheaper to flip a breaker!

Regards,

Rob
 
Mine has a 50amp breaker. With the size of batteries and planned loads you might want more with a large inverter especially. Go for a blue seas, mine had a sea dog that would disconnect but the physical indicator that it was tripped didn’t go, so I was scratching my head why I had no power.
 
When I first took my boat down to Rodgers Marine Electronics in Portland, to add a radio and AIS, one of the things they identified was that the wire to the Windlass was too small and that it needed a larger fuse. They rewired it with the right size, and put in a 50 amp breaker. I don't know if the factory installed the windlass or if it was Outboard Service in N. Cal. but they said it was fortunate that I had not run the windlass with any kind of a load on it, up to that point.

Harvey
SleepyC :moon

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