Circuit Breaker Lifespan - 2015 R31 (CB)

[JeffreyAC77]

I have now had 2 different circuit breakers malfunction in the past year. One of the main breakers behind the rear cockpit seat and now the breaker on the Onan genset. This doesn't seem normal to me as I believed circuit breakers themselves should function properly for 10-20 years....am I nuts? Both breaker just don't work anymore (they're dead).

 

[Brian John]

When you say failed, in what way? Are They tripping? They won't reset? They are closed/on but do not pass voltage.

Circuit breakers are thermal-magnetic devices composed of metallic parts. On a boat, they are exposed to high humidity which can result in corrosion and rust additionally they can take a beating in rough seas. Breakers that are exposed to high current regularly can have metal fatigue of the bimetallic trip and if the circuit breaker has tripped due to a fault this can damage the mating surface of the power contacts.

Then there are manufacturing issues, my company tested circuit breakers for proper operation per manufacturer specifications and while the failure rate was low we did have failures.

So in short yes circuit breakers can fail

Thermal is for overloads,
Magentic for instantaneous faults.

 

[JeffreyAC77]

When you say failed, in what way? Are They tripping? They won't reset? They are closed/on but do not pass voltage.

Circuit breakers are thermal-magnetic devices composed of metallic parts. On a boat, they are exposed to high humidity which can result in corrosion and rust additionally they can take a beating in rough seas. Breakers that are exposed to high current regularly can have metal fatigue of the bimetallic trip and if the circuit breaker has tripped due to a fault this can damage the mating surface of the power contacts.

Then there are manufacturing issues, my company tested circuit breakers for proper operation per manufacturer specifications and while the failure rate was low we did have failures.

So in short yes circuit breakers can fail

Thermal is for overloads,
Magentic for instantaneous faults.

Thanks Brian. I believe both failures were just not passing through voltage. Recent example is the Onan genset breaker needs replacement as there is power to it, but the genset will not turn over and the breaker is not tripping. We have ordered a breaker replacement with fingers crossed. I guess i was under the impression that breakers should last 10+ years ( especially since we very rarely use our genset) under normal circumstances and we have not experienced any stress on the unit itself.

 

[freedomvango]

Thanks Brian. I believe both failures were just not passing through voltage. Recent example is the Onan genset breaker needs replacement as there is power to it, but the genset will not turn over and the breaker is not tripping. We have ordered a breaker replacement with fingers crossed. I guess i was under the impression that breakers should last 10+ years ( especially since we very rarely use our genset) under normal circumstances and we have not experienced any stress on the unit itself.

an easy verification is bypassing the breaker and seeing if it works momentarily. I absolutely would not leave it there, but in an offshore situation where you need it, it wouldn't bother me to try it

 

[Brian John]

an easy verification is bypassing the breaker and seeing if it works momentarily. I absolutely would not leave it there, but in an offshore situation where you need it, it wouldn't bother me to try it

If you opt to bypass the circuit breaker I would use a jumper with a fuse or circuit breaker inline for protection during the test.

 

[freedomvango]

If you opt to bypass the circuit breaker I would use a jumper with a fuse or circuit breaker inline for protection during the test.

When you are in the middle of nowhere that's not always an option. But yes if that was available it's the best way.

 

[Brian John]

When you are in the middle of nowhere that's not always an option. But yes if that was available it's the best way.

Ideally, you should have spare fuses and I always have some jumpers in my electrical kit, with DMM and clamp-on.

 

[freedomvango]

Ideally, you should have spare fuses and I always have some jumpers in my electrical kit, with DMM and clamp-on.

My experience, you are the absolute rarity. Totally agree with you

 

[Brian John]

My experience, you are the absolute rarity. Totally agree with you

It is a tough choice when outfitting a boat for all tools and knick-nacks you might need for any possible unseen emergencies, only to see when you need the component it is corroded or rusted. And it is amazing how fast some stuff rusts. I have switched to imitation Harbor Freight Pelican knockoffs and after 3 seasons my tools remain in decent shape. The problem is I can't find those damn alligator clip jumpers.😛😱

 

[freedomvango]

It's certainly easier for you and a 31 then me and a 23