Difference between a “solar shutoff breaker” “fuse” and “Thermal Circuit Breaker”

[Gus the Bus]

Hi!
I’m trying to understand the difference and where to best utilize each object.

Solar disconnect:
Looks to be a normal breaker between the panels and MPPT.

250amp Fuse:
Looks to be between battery and Bus Bar.

Thermal Circuit Breaker:
I’ve see. These between Bus Bar and Mppt and inverter.

I’m trying to understand the differences between them, how big I need to go, and anything else I don’t know that I don’t know about them.

 

[chrisski]

When I hear these:

solar disconnect, I think of something that removes power from the array, such as the firefighters have to go on the roof. Kind of like a deadman’s switch. Big switch that can’t be missed if needed in car of emergency. THe type of disconnect I’m describing is a bit more expensive,

Fuse: Can be cheaper, quicker blowing, and or take up less space than a circuit breaker.

Thermal Circuit breaker: I don’t know if these are thermal or magnetic, what I care about is if they are rated for the correct DC voltage and amperage mine want. The ones I used are rated to constantly turn things on and off. I use circuit breakers for solar panels, and fuses for batteries and other devices attached to a busbar.

 

[Gus the Bus]

Thank you!

solar disconnect: is that rated to automatically pop as well? Or manual operation only?

Fuse: got it.

Thermal circuit breaker: “The ones I used are rated to constantly turn things on and off.” - why / when would you turn off? (when doing maintenance, any other time?) if no, then why not to the battery as well.

Do you think the solar disconnect is not as good as the Thermal C Breaker?

Appreciated!!

 

[chrisski]

“The ones I used are rated to constantly turn things on and off.” - why / when would you turn off?

I use midnite solar circuit breakers on my solar panels. When I’m storing my RV and want the panels off, I trip those. Troubleshooting also.

solar disconnect: is that rated to automatically pop as well? Or manual operation only?

I don’t have experience with those, but the ones I looked at are manual only and sit on the outside of an enclosed metal circuit breaker box.

Do you think the solar disconnect is not as good as the Thermal C Breaker

The solar disconnect me circuit breakers are two different things. THe midnite solar website has them for sale and I think that’s because of a change in code saying builds need this. This really is to keep the panels on the roof powered down. Think of this as someone has to be around.

For the circuit breakers, that is when you’re not around, or the fault happens so quick it needs to trip in fractions of a second. For the AC side, that could be when you plug too many high wattage appliance into a 15 amp circuit,

 

[Gus the Bus]

Dig it thank you!