What caused this? Faulty breaker?

[TankFish]

I have in line fuses between my panels and my 24v and 48v panels separated. The breaker did not pop! I smelled a foul electrical burning and found this in my feed in panel. None of my other breakers were burnt up, just this one. It was burnt up on the side that goes to my SCC. I was able to flip the breaker and get it all disconnected before a serious fire.

My question is, what was the cause? Was it the panels feeding to much? I figured that would have burnt the top side, where they go in if that was the case. I could be way off. Any ideas?

System was fine with no issues for 8 to 9 months.

My setup. 6x 12v 200w panels, 6x 24v 320w panels. Separately ran to separate SCCs. Victron Quattro 5k 48v. 24 320ah cells into 3 packs for 3 24v batteries with Overkill BMSs. In line fuses between each string of panels 15a.

I am just trying to figure out what I did wrong, so I don't make the same mistake or if you think I got a faulty breaker or both. Thanks!

 

[BentleyJ]

Its difficult to say for sure but the heat seems like it was concentrated on that connection point not inside the breaker. High resistance for some reason. Incorrect torque or perhaps the factory connection of the lug to the internal breaker components. Maybe worth taking the breaker apart to see if its possible to determine the origin of the hot spot.

 

[Bud Martin]

Yep, it burnt up due to poor connection. It will be a good idea to check all connections and use thermal gun to check temperature every six months or so.

 

[TankFish]

Its difficult to say for sure but the heat seems like it was concentrated on that connection point not inside the breaker. High resistance for some reason. Incorrect torque or perhaps the factory connection of the lug to the internal breaker components. Maybe worth taking the breaker apart to see if its possible to determine the origin of the hot spot.

I'll have to tear it apart tonight and look inside for sure. I'd like to solve the issue, well at least get to the root, so I don't run into this again.

Throwing a lower amp breaker on for now, since I don't need a 100a. I was planning to increase wire guage and add some more panels once i caught up on funds, but I'll hold off to make sure it wasn't my fault. If it was the breaker, I'll have to choose a new company. My 53a breakers have never done this on my other two builds or the current 24v side. Might see if the company that makes my 53a, has larger breakers, if it is the breaker.

 

[TankFish]

Yep, it burnt up due to poor connection. It will be a good idea to check all connections and use thermal gun to check temperature every six months or so.

I have gunned it every month since it was a new build. Kind of a self assurance to myself i do with a new build. Never saw any issues there. The wire was nice and flat, well screwed in. I'm going to do what BentlyJ recommended, and tear apart the breaker when I get back home. See if it was internal. Hopefully I can pin point the issue and post my findings. If it is the breaker, maybe help others steer clear of the brand. Thanks for the input!

 

[TankFish]

I should add, this happened during a heat wave we had here in CA, 105 degree day, nothing to terrible, but a hot day for sure. Did not affect my 24v side or my other 10 panel setup on my other build that is much higher amps.

 

[Bob B]

99% likelihood there was a loose connection at that burned terminal. Heating an cooling can cause it to get loose over time.

 

[TankFish]

99% likelihood there was a loose connection at that burned terminal. Heating an cooling can cause it to get loose over time.

Hopefully that's all it was, checking all of my other connections now on both builds. All seem to be tight. Doesn't mean one didn't loosen up though. Once I get home, that breaker will be dissected and see both probabilities. Thanks for your input!

 

[robin73]

Hi, small question :
what was the size of cable because on the photo the red cable does not seems to be able to handle 100A.
the circuit breaker is here to protect the cable so that it don't act as fuse.

If you have plug a small cable on a 100A circuit breaker and in case of high current coming from a faulty PV array, the cable will burn before the circuit breaker kick the connection.

How was setup your PV connected to this circuit breaker ? all in series or in series and parallel ?

 

[not a sparky]

I have in line fuses between my panels and my 24v and 48v panels separated. The breaker did not pop! I smelled a foul electrical burning and found this in my feed in panel. None of my other breakers were burnt up, just this one. It was burnt up on the side that goes to my SCC. I was able to flip the breaker and get it all disconnected before a serious fire.

My question is, what was the cause? Was it the panels feeding to much? I figured that would have burnt the top side, where they go in if that was the case. I could be way off. Any ideas?

System was fine with no issues for 8 to 9 months.

My setup. 6x 12v 200w panels, 6x 24v 320w panels. Separately ran to separate SCCs. Victron Quattro 5k 48v. 24 320ah cells into 3 packs for 3 24v batteries with Overkill BMSs. In line fuses between each string of panels 15a.

I am just trying to figure out what I did wrong, so I don't make the same mistake or if you think I got a faulty breaker or both. Thanks!

OMG, i have the same brand breaker, only 125/125. the second time i Turned on my 5 month new MN5048DIY, it Failed on me, i had it between my 50v Li Ion Server rack batteries and the 5K Midnite Solar Diy Inverter / Charger. it Fried some 4 wire Fuse ? or current limiter and now my Unit won't power on. Midnite solar has a Vague Manual of this Chinese Inverter. No Schematic Diagrams. i submitted a Ticket, and have Not heard back from them. DO NOT BUY THIS 5K, 48v DIY Inverter unless you can repair it yourself ( good luck with discovering what the part is ? i have pictures ) or you are willing to PAY for Shipping Both Ways.i don't even know if they will honor the ONE YEAR Warranty, yet
i am not an Electricain. i have Built my own 48v system with Tesla & Leaf EV Battery Modules, with a 4448 MagnasinePAE. Classic 200, 480w QCell Panels. if anybody has any Input that can help me, i would appreciate it as The NEW Guy. Thank You

 

[BentleyJ]

i Turned on my 5 month new MN5048DIY, it Failed on me, i had it between my 50v Li Ion Server rack batteries and the 5K Midnite Solar Diy Inverter / Charger. it Fried some 4 wire Fuse ? or current limiter and now my Unit won't power on.

I don't think its the breaker that failed. Seems like something else inside the inverter failed (shorted out) and melted those 4 fuse links. Even if you can determine the current rating of those melted fuse wires and replace them its likely the same thing will happen again unless you can determine if a power FET or BJT or something else failed which caused the fuse to do its job in the first place.
I've had to replace 2 BJT's (half the "H" bridge)in an AIMS that failed in a dead short condition. In this case it was my fault, I did something stupid with the inverter.

 

[D71]

OMG, i have the same brand breaker, only 125/125. the second time i Turned on my 5 month new MN5048DIY, it Failed on me, i had it between my 50v Li Ion Server rack batteries and the 5K Midnite Solar Diy Inverter / Charger. it Fried some 4 wire Fuse ? or current limiter and now my Unit won't power on. Midnite solar has a Vague Manual of this Chinese Inverter. No Schematic Diagrams. i submitted a Ticket, and have Not heard back from them. DO NOT BUY THIS 5K, 48v DIY Inverter unless you can repair it yourself ( good luck with discovering what the part is ? i have pictures ) or you are willing to PAY for Shipping Both Ways.i don't even know if they will honor the ONE YEAR Warranty, yet
i am not an Electricain. i have Built my own 48v system with Tesla & Leaf EV Battery Modules, with a 4448 MagnasinePAE. Classic 200, 480w QCell Panels. if anybody has any Input that can help me, i would appreciate it as The NEW Guy. Thank You

I'd say that burned up part was a current divider - reduces current for something in there. I'd bet whatever it fed is problematic too.... bad. With no schematic strongly suggest you return it and get the warranty work. You paid extra for a warranty. That is an expensive rebranded chinese inverter... looks similar to the powmr 5000. .... I would again send it back to get the 1 year warranty work performed. These chinese AIO (all in one) inverters have a short life or so it seems. A 1 year warranty is typical if that.
I think the mass maker relabel company is Voltronic for most of these Chinese inverters.

Edit added as pointed out by other poster it could be a fuse section too. It is designed to be removed replaced. Even still bet the end item is bad. Return it for warranty

 

[D71]

OMG, i have the same brand breaker, only 125/125. the second time i Turned on my 5 month new MN5048DIY, it Failed on me, i had it between my 50v Li Ion Server rack batteries and the 5K Midnite Solar Diy Inverter / Charger. it Fried some 4 wire Fuse ? or current limiter and now my Unit won't power on. Midnite solar has a Vague Manual of this Chinese Inverter. No Schematic Diagrams. i submitted a Ticket, and have Not heard back from them. DO NOT BUY THIS 5K, 48v DIY Inverter unless you can repair it yourself ( good luck with discovering what the part is ? i have pictures ) or you are willing to PAY for Shipping Both Ways.i don't even know if they will honor the ONE YEAR Warranty, yet
i am not an Electricain. i have Built my own 48v system with Tesla & Leaf EV Battery Modules, with a 4448 MagnasinePAE. Classic 200, 480w QCell Panels. if anybody has any Input that can help me, i would appreciate it as The NEW Guy. Thank You

Similar specs As stated by Midnite Solar you are buying based on "Trusted Name" Advice - Get your warranty work done.

 

[farmhand]

Yep, it burnt up due to poor connection. It will be a good idea to check all connections and use thermal gun to check temperature every six months or so.

I'd say this, I bought a decent PV Combiner with Diodes and saw in a review to check every connection. Indeed there were several not torqued right, and the (-) wire from T-strip to breaker overtightened and had a hairline crack in the terminal block.