Thermal circuit breaker and question

[twsykes]

Hey guys, so I have been chasing a low voltage problem at the graphs and I found it but what’s odd is how it works. So the thermal 40a breaker was tripped and once I pushed it back in the voltage to the graphs went from 11.5 to full battery voltage 12.5.

What’s odd to me is that I would have thought that the breaker when tripped would interrupt the overall voltage not lessen the amount to the fuses. Any thoughts on this other than thinking the breaker is just faulty and is not working right.

Incidentally the breaker has not tripped since this happened. thoughts?

 

[SLOmofo]

Replace it.
It sorta failed already once. It's weak and/or has resistance within it. You could test it...see below.
One of the best tools in your box is learn and use the volt drop method for electrical problems. https://www.aa1car.com/library/voltage_drop_testing.htm
This is another tool for parasitic draw. Wish I knew this long ago wasted mucho time letting things time out and go to sleep. https://us.autologic.com/news/testing-parasitic-draw-via-fuse-voltage-drop
I know someone who had a Home Wellness check up on her home. He shorted all the circuit breakers to test them. All were OK. After a while she found that her electric oven would only heat two burners and the oven, any more and the breaker would pop. Long story short, the wiring to the receptical, receptical, and then oven were replaced. I had suggested replacing the circuit breaker first in the beginning.

 

[SLOmofo]

Another thought. Why was the breaker tripped in the first place? 40 amps is a lot of potential.

 

[twsykes]

Good question. I have tested all circuits and the combined the amperage draw does not get near 40A load but if I recall correctly I might have popped some fuses when doing some wiring different things which might have caused the issue. That ire is no draw that I can see... I guess I am wondering why Allison used that instead of an all off blue seas switch that is a thermal protected like my other ally has.

 

[SLOmofo]

Usually the fuse/breaker is twice as large as the circuits running current usage. It is because of the surge on start up.