Another 12 vdc question

Re: Another 12 vdc question

Ideally, you want every (positive) wire in the battery system to have a fuse that limits the maximum amount of current available such that if there was a short, the wire will not catch anything on fire. (generally, only fuse one side of any circuit--you should not be fusing ground wires except in very limited/specific circumstances).

So, ideally, you would want a fuse on the positive bus bar to the breaker box based on the current carrying capacity of the wire and the capacity of the breaker box...

If, the positive wire from the battery to the breaker box is short, well insulated and kept away from sharp edges/damage, many folks probably would not place a fuse on the + bus bar connection...

I am sure that folks here can give you part numbers/suppliers of fuse/breaker blocks that they would recommend.

Myself, I would fuse at the battery too, then run an appropriate size wire to the breaker/distribution box... Especially if this was in my home or somewhere a fire would be dangerous and/or expensive. And, each leg (assuming they are smaller gauge wires) should have an appropriate fuse/breaker protecting the downstream wiring and devices.

Batteries themselves have massive amounts of current available and will fry most wires (an can even damage heavy gauge wires used for busing battery banks together). If you have never had a battery/DC wiring harness short--count yourself lucky. Large battery systems, in some ways, are actually more dangerous than the 240 VAC wires that come into your home... They are designed to carry the fault currents, and the pole transformers are designed to limit maximum inrush currents to "safe limits"... And DC arcs are much harder to stop than AC arcs--so larger AC fuses and breakers are not always appropriate to use in DC battery systems as safety devices (an AC breaker will arc and can fail when operated on low voltage/high current DC circuits).

-Bill