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Circuit Breaker question

Old 10-28-2020, 01:59 PM
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Default Circuit Breaker question

I need to replace several circuit breakers on my switch panel. Have removed a couple of them to see what amperage I need to replace them with. There are no markings on the old breakers to tell me what amperage current ones are, so I don’t know what to order.
the three I want to replace control the bilge pump, the pump for the live well and the night time running lights.
The back of the breaker may have the answer but they are so caked with grime that when you try to wipe it off the paper comes off. The new switches come in 5, 10, 15, and 20 amp.
pics below to help understand.


Current breaker

Current realer on back


Faulty breaker that was probably replaced before

New breaker I will order.
Old 10-28-2020, 03:07 PM
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That looks like either a 14 or 16 gauge wire, so I would use a 10 or 15 amp breaker
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Old 10-28-2020, 03:15 PM
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Thank you for your advise.
Old 10-28-2020, 04:45 PM
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For non motor loads: you size the fuse to the smallest wire in the circuit. so for your nav lights, you will most likely size based off the pigtails coming off the device. Typically 18awg. Could vary though. Max amps through 18awg is 20 amps. Nav lights (especially LED) draw no where near that so you could always size smaller as well. What type nav lights are they and do you know the pigtail wire size?

for motor driven loads: you fuse to what the manufacturer tells you to fuse at. So look on the bilge pump and livewell pump.
Old 10-28-2020, 07:00 PM
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Agree with the feedback of motor vs non motor loads. However, the pumps might be hard if you didn’t replace them recently and they are old. I did an identical replacement on my bilge but the fuse size went up from the one I had in my panel.


Depending on your boat, check their website for old manuals. I have the original one from the previous owner but also downloaded one from Grady. The manual should have those details as to what was originally there.
Old 11-03-2020, 09:21 AM
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Ok, my new breakers came today. The only description on the breaker connections is line on one and load on the other. Can anyone tell me which one I put the red (positive) connection on. Dumb question but don’t want to wire backwards.
Old 11-03-2020, 09:31 AM
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Originally Posted by Onebadlarry View Post
For non motor loads: you size the fuse to the smallest wire in the circuit. so for your nav lights, you will most likely size based off the pigtails coming off the device. Typically 18awg. Could vary though. Max amps through 18awg is 20 amps. Nav lights (especially LED) draw no where near that so you could always size smaller as well. What type nav lights are they and do you know the pigtail wire size?

for motor driven loads: you fuse to what the manufacturer tells you to fuse at. So look on the bilge pump and livewell pump.
Presumption being that the wiring to and from the pump is appropriately rated.
Old 11-03-2020, 09:40 AM
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Line is power supply, load is going to the motor/switch/lights/etc.

Rule pumps usually have breaker/fuse size printed on motor tops. I think a rule 2000 gets 15A breaker, rule 1000 gets a 10A. Look on the motors.

If your nav lights are LED, a 5A will do, but so will a 10. If incandescent, 5A would probably work, I'd go with 10.
Old 11-03-2020, 09:49 AM
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Thank you Corndog. Now I’m hungry for lunch😀
Old 11-03-2020, 03:32 PM
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You only really need 10-15-20 amp fuses for the pumps and lights.
Old 11-05-2020, 05:58 PM
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I would try to identify the equipment, look up the installation manuals, and use whatever fuse is recommended.

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