Moderated Discussion Areas
ContinuousWave: Small Boat Electrical
|Author||Topic: Fuse Size|
posted 08-11-2009 01:55 PM ET (US)
I have a bait tank that utilizes two bilge pumps and I have them both wired to one circuit switch. One pump draws 2.5 amps and the other draws 1.5 amps. I'm not really sure what size fuse to use at the switch. I've been using a 5 amp assuming that the combined load is just shy of that. Does this sound correct?
posted 08-11-2009 02:44 PM ET (US)
The fuse should be sized to protect the smallest gauge wire in the circuit in the event of a short circuit.
posted 08-11-2009 03:18 PM ET (US)
posted 08-12-2009 08:21 AM ET (US)
In a branch circuit with two loads whose total current demand will be 4-amperes, a fuse rated at 5-amperes is a good choice.
The purpose of fusing the branch circuit is to prevent damage in the event of an overload current on that branch circuit. In the case of this particular circuit, we can assume it is on a small boat. Regulations require that all wiring on a boat be done with a wire of a minimum of 16-AWG. The current carrying capacity of a 16-AWG conductor is far in excess of 5-amperes. Thus using a fuse of 5-amperes protects the conductor against any current overload, as well as protecting the devices.
posted 08-12-2009 02:16 PM ET (US)
Thank you Jim for the detailed info.
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