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Author Topic:   Outrage Main 50 amp breaker
Smithsm posted 07-09-2008 02:00 PM ET (US)   Profile for Smithsm   Send Email to Smithsm  
I am in the process of potentially reinstalling a circuit breaker back into the electric box Boston Whaler put on my Outrage 20. A previous owner had removed [the circuit breaker] and connected the wires together. I contacted Boston Whaler who said the boat came with a 50-ampere circuit breaker. My friend's boat, Bulldog, also a Revenge 20 of same era, has a 50-ampere [circuit breaker located in the stern splash well close to the battery]. The motors each have 20-ampere fuses to isolate them from the battery in case of a starter motor short.

What on this boat could possibly need a 50-ampere breaker ? The only idea we have is potentially a trolling motor, but that is not likely to be put on this boat or a Revenge. Explain why Boston Whaler would use a 50 amp breaker, or use any breaker at all given that the [helm] console has a fuse panel for individual devices.

jimh posted 07-09-2008 03:38 PM ET (US)     Profile for jimh  Send Email to jimh     
Branch circuits are protected by current over-load devices, usually circuit breakers or fuses. The over-current protection is located as close to source of power as possible. The over-current device is sized to be appropriate to the load of the branch circuit and the size of the conductors carrying the current, whichever is the lower current factor.
jimh posted 07-09-2008 09:05 PM ET (US)     Profile for jimh  Send Email to jimh     
You misunderstood the purpose of the 20-ampere fuses in the outboard motor. The purpose of the 20-ampere fuses in the outboard motor is to provide over-current protection for the branch circuits which are fed by those fuses. The fuses will play no role whatsoever in the case of a short circuit in the starter motor. The starter motor current does not flow through those fuses. In fact, the starter motor winding is such a low resistance that it more or less presents a short circuit to the battery. For this reason the starter motor circuit is generally not protected by a circuit breaker or a fuse.
btb posted 07-10-2008 10:37 AM ET (US)     Profile for btb  Send Email to btb     
I just replaced a 50 amp circuit breaker on my 1991 16 SL - sounds like the same location as yours. The only thing it protects is a short in the main wire going up the service tunnel - as the original wiring all goes into circuit breakers at the helm. Any non-original wiring may not be adequately protected. I figured it was worth it.

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