Blew a 250 amp fuse the other day. How to avoid this

[Mike90250]

With proper wiring and fuses, even extreme conditions should not smoke wires. I'm glad you were not hurt.

A 250A fuse is to protect 4/O wire. That's big wire, and very unusual to find in an RV

1/O wire is roughly rated to handle 150A, That's still pretty big wire. You need to review the wire gauge used in your system and use the right size fuses. Fuses/breakers are
there to protect the wires. Nothing else. Some DC breakers are rated for "switch duty" and can be used for daily on - off usage.

This is one of the reasons 12V systems with 3000w inverters are dangerous. Inadequate wiring "works" for a long time, and then something bad happens and you get smoke.

styles of fuses in this chart here: https://www.bluesea.com/support/arti...t_Installation

https://lugsdirect.com/WireCurrentAm...ble-301-16.htm or https://www.bluesea.com/resources/1437

[Skwidward]

Just 1 week into full time RVing and still at a park with hookups to iron out kinks, of which there are many (don't get me started... I feel like it would have been better to just build my own RV).

My solar set up has been performing marvelously, however. Full sun I get around 400-500 Watts from 6x 100 Watt flat mounted panels 2s3p.

Quick background so the following will make sense: my inverter's "ac out" is wired into my RV's ac breaker box in place of the original shore power cord. My shore power cord is wired into my inverter's "ac in." It is an inverter/charger with built-in transfer switch. This way when I plug into shore power it will automatically charge my batteries while also supplying my RV with shore power.

We moved to a different camp site, and the new site evidently has an issue holding a 30 amp plug in its shore power outlet. So the 30 amp plug unplugged itself from shore power without letting us know, which caused the inverter/charger to flip its transfer switch and power the air conditioner with the battery bank. In no time at all my wife and I were lifting the bed (my solar components are located under the bed) fire extinguisher in hand to inspect the burning smell and smoke!

We had no idea what was going on. My immediate thought was that I had F'd up royally with my wiring or something. It took us a while to figure out what had happened, and that, in fact, the system had done its job well--one the 250 amp fuses had blown. This is great. I'm super glad the fail safes I installed worked and saved us from a fire. However, I'm thinking about how I can prevent this from happening in the future. I mean, the loose plug socket isn't an uncommon problem, and what if the power at the campsite goes out at night and I'm running the air conditioner? I don't want to wake up in the middle of the night to burning smells and smoke even if it is just a blown fuse.

My immediate thoughts were to replace the 250 amp fuse with a 150 amp breaker (150 amp so I can still run the microwave off the batteries if needed). This way if I'm plugged in with the air conditioner on and the park's power goes out, the breaker will pop, and it will pop way earlier than the 250 amp fuse causing less stress to the whole system; and I will be able to just reset the breaker once everything has cooled down.

I don't know. A flipped breaker just seems a bit less dramatic and scary when compared to a burnt out fuse.

Anyone deal with this before or has a set up like this?

Cheers

[Skwidward]

Just 1 week into full time RVing and still at a park with hookups to iron out kinks, of which there are many (don

EDIT: continued in next post