Join Date: Sep 2008
Location: Victoria B.C. Canada
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Re: What size AC breaker?
ABYC allows the main DC fusing to be up to 150% of the ampacity of the wire. This is strictly for short circuit protection, not overload.
They do not allow fusing for loads to be any higher than the wire ampacity.
Most AC wiring on a boat for 15 amp circuits is 14 awg, which has an ampacity of 30 outside of engine spaces - 90 C rated, unsheathed and not in bundle or conduit. The breaker on such a circuit should not exceed the 15 amp outlet rating.
If you have 30 amp inlet and supply there should be a double pole 30 amp breaker within 10' (wire length) of the inlet and that feeds the individual circuits which are usually 15 amp for outlets, water heater, etc.
Living aboard in Victoria Harbour
Last edited by mitiempo; 09-26-2012 at 04:53 PM.