Courtesy “B” circuit breaker Legend 40.5

[fero]

Hello again,
The CB on the main switch panel suddenly will not close (when I try to close it the small indicator led will light but switch lever will spring back). The only light I could associate for sure with this CB is the gooseneck light over nav table. Any similar experience?
Thanks.

 

[Rich Stidger]

Need more info. Exactly which breaker and what is it's label?
I think a CB that will not reset means one of two things. Either it is grossly overloaded and instantaneously trips while you are trying to reset it, or it has become defective.
Try this- Turn off the main 50A 12V CB. Then reset the breaker in question. If it remains closed with no current passing, then I think that the subject CB may not be defective. Then turn on the main 50A breaker. If the subject CB then trips, I would suspect that the subject breaker is grossly overloaded. If overloaded you then need to find the cause of the load.
The other possibility is that the CB trips at a much lower current than it's rating, in which case it is still defective.
And lastly, when you try to energize the CB, what does the ammeter on the panel show? If the answer is lots of current then that further supports the theory that the CB is grossly overloaded. The fact that the small red LED lights up tells me that power is flowing through the CB to the loads.

 

[fero]

Thanks Rich for good comments. I followed them with results indicating the faulty CB (not closing with main CB open, no change in amps). Do you know the make and model of a replacement? I have not yet opened the main panel, any pointers on changing the CB would be greatly appreciated. The label says. Courtesy B and it is the 5th from the top the left column of DC breakers. Regards
Frank

 

[Rich Stidger]

Frank,

I have replaced some of my CB's with the Blue Sea units. Be sure to get the toggle color to match your other CB's. If convenient, remove the defective one and take it with you to purchase the replacement. But I don't think you will have any problem matching it. I suspect that it is probably a 10A unit, but the rating is labeled on the side which can't be seen until removed.
The tips for replacement are to turn off the main 12V breaker and disconnect any 120V A/C power to the boat to be certain that nothing is "live". You will have a 2-3 wires to loads on the breaker- be sure to count and identify so you get all back correctly. One wire will be to the LED indicator and the others to lights onboard.
Be careful not to drop the screws!
My panel is labeled a bit differently- see attached. I think my "Courtesy Lights" also feed the U-shaped lighting around the companionway.

 

[Rick D]

+1 Rich. I have replaced several CBs and added a couple of spares which you may wish to consider. On mine, there is a bar that has to come out to release one of the switches. I also used Blue Seas; slightly different but fitment is fine.

 

[fero]

Thanks Rich and Rick for your help.

 

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[fero]

+1 Rich. I have replaced several CBs and added a couple of spares which you may wish to consider. On mine, there is a bar that has to come out to release one of the switches. I also used Blue Seas; slightly different but fitment is fine.

Well one year later I got to trying to replace the CB (Blue Seas) but found the same bar in the way. Living on board in Caribbean for now it wasn’t practical to shut down fridge, freezer, etc. So temporary I put the « Courtesy B » loads on « Courtesy A » CB. Both are only small loads for the 20 Amp CB. Will correct it once hauled out.

 

[Rich Stidger]

Will correct it once hauled out.

Sounds like a plan.