DC DIN rail breaker up in smoke and now looking for replacement

[Shimmy]

is there not supposed to be an isolated pocket and divider with a magnet to extinguish an arc / spark?

I thought as long as the arc was isolated from the front it is good, but standards vary. The damage though looks like heat only though and thermal overload even cleared due to overheating.

 

[RVLiFe]

@Will Prowse, maybe you could start taking breakers, inverters, controllers, shutoff switches as well as other components apart to see what’s really inside and how they stand up. There is a reason some components are UL listed and certified and others aren’t. We need to know what components we can trust and make sure those companies are the only ones we buy from. Likes on Amazon are not enough apparently. I’ve been hearing that even the big RV component manufacturer Lippert has its own SCC now but it has been known to start on fire.

 

[Tecnodave]

Well, I am impressed.....this is a real breaker....the fail mode is absolutely poor connection, not a failing of the breaker itself.

Besides always doing a connections test I use a Fluke 62 Max Infrared thermometer and do a thorough heat source search. Thanks for posting the pic’s

 

[Mattb4]

Can't be sure from the pictures, but why it eventually stopped working from what I can make out, was that the screw down contact point melted enough to open the connection. It was not from the breaker tripping on overload.

 

[MattiFin]

I’d like to hear a professional opinion about this breaker and what it is lacking or what someone likes about it.

Internals look like real circuit breaker or as in this case reasonable copy/counterfeit.
Impossible to say more accurately how it performs without extensive testing but at least its got the basic functional blocks of circuit breaker inside.

 

[x98myers7]

i'm just going to order a listed Midnite disconnect. not going to take any risks for $35.

 

[rhino]

i'm just going to order a listed Midnite disconnect. not going to take any risks for $35.

This ^. If you did this you wouldn't have to worry if it was the breaker or not. As it is you can't even tell who the manufacturer of that breaker that failed is. Why take the risk on such a critical safety component? Just because someone else recommended it does not make it safe.

 

[FilterGuy]

Well one day I was going to take a chitaixi s apart to see what was inside. Haven’t done that. Maybe I’m dumb but is there not supposed to be an isolated pocket and divider with a magnet to extinguish an arc / spark? @Hedges @FilterGuy would you care to enlighten us please?

if you look at the pics, it seems pretty clear the problem was NOT due to arcing. It was due to a bad connection at the input port.

 

[12VoltInstalls]

if you look at the pics, it seems pretty clear the problem was NOT due to arcing. It was due to a bad connection at the input port.

Absolutely. No question there!

However, because I don’t know, I’d like an engineer’s perspective on how it is built and to what standards it succeeds or falls short as a DC breaker.

 

[Quattrohead]

Correctly installing copper wires into terminals involves several retightening. I do not use ferrules on my system and have never had a connection failure......BUT.....I have found the screw terminals will be loose in less than 20 minutes due to the fact that pure copper wire does compress over time. I always go back and retighten all screw connections at least after the first hour of operation, and again after a very hot spell producing high power. Im running 40-60 amps from each combiner into each charge controller.

I cannot even remember just how many system failures that I have found in high power electrical systems, way too many to count.

Lots of years in the electrical industry has taught me to look at first inspections for loose connections in system failures.

Bolded text is a must. I experiment rather a lot with my systems and have found several connections loose after a few weeks.

 

[Quattrohead]

I’d like to hear a professional opinion about this breaker and what it is lacking or what someone likes about it.

Looks good to me. Has magnetic and thermal trips. Magnetic for high instant overloads and thermal for festering slight overloads.

 

[Quattrohead]

BTW I don't like ferrules. The more parts you have in the way of a connection, the more likely a failure is, KISS.
I think they are used more to keep strands of wire from escaping the clamping system and possibly causing a short rather than making a better electrical connection.
I will chat to my brother about this....he builds super high power power supplies for oil drilling systems. Failure is 100% not an option in a $25k power supply.

 

[rhino]

BTW I don't like ferrules. The more parts you have in the way of a connection, the more likely a failure is, KISS.
I think they are used more to keep strands of wire from escaping the clamping system and possibly causing a short rather than making a better electrical connection.
I will chat to my brother about this....he builds super high power power supplies for oil drilling systems. Failure is 100% not an option in a $25k power supply.

If your are using cable with fine strands and the clamping mechanism is simply a screw down then you must use ferrules otherwise the screw/bolt will cut off strands of wire as you tighten.

 

[Quattrohead]

If your are using cable with fine strands and the clamping mechanism is simply a screw down then you must use ferrules otherwise the screw/bolt will cut off strands of wire as you tighten.

Indeed but most new stuff now has clamps not screws.

 

[rhino]

If you are doing more DIY non-all-in-ones there are a lot more cases of screws being used.. I have power blocks where I switched from heavier gauge aluminum to fine strand copper and lot of these busbars all use screws.

 

[T Pasto]

Are these any good? I’ve seen them posted on here before but don’t recall the reviews.

DC Miniature Circuit Breaker, 2 Pole 500V 25 Amp Isolator for Solar PV System, Thermal Magnetic Trip, DIN Rail Mount, Chtaixi DC Disconnect Switch C25 https://a.co/d/46nZs5P

Those are the same ones I use and have had no issues. The install guidance is a bit confusing because of the + and - on the breakers. These are none directional polarity but you do want the positive and negative wires passing through the correct breaker as they are marked. I can't really guess how that impacts interaction between the two breaker's, but I've seen a YouTube vclip id that showed a user of similar designed breakers griping that they burned up but it also shows the clearly incorrect connection as he illustrated how he could make it smoke.