DC MCB Polarity

[occuplus]

When i connect battery/PV to upperside
1> Positive
3>Negative is it correct?

2 and 4 s for load?

 

[wpns]

Sure looks like it, in which case yours is probably wired wrong (unless the person who wired it was using black for positive and red for negative. You would think that never happens, but you would be surprised how many times that happens in this forum). Check with a DVM to be sure.

 

[efficientPV]

Depends on what you call the load and what will be the fault it is protecting against. It could be correct.

 

[wpns]

Depends on what you call the load and what will be the fault it is protecting against. It could be correct.

I’m saying that positive should be on terminals 1 and 2

 

[robbob2112]

The top of that breaker is the device with the higher potential and the bottom is the lower potential -

So top + & - is to the pv array
bottom + & - is to the mppt

 

[robbob2112]

There is a video out there where a guy says those are dangerous and he hooks it up backwards and it catches on fire a few minutes after he turns it off.... well duh, hook a polarized breaker up backwards and havok ensues.

 

[robbob2112]

I would also like to point out there are a number of teardown videos where people drill out the rivits on the cheap junk DC breakers and what they find is 2 bolts, a piece of copper mesh and the spring out of a ballpoint pen soldered to the lower contact, the rest hollow .....

So you get enough current to melt the solder it flips open and you are done ... of course that current is totally random and has nothing to do with the markings...

Those are why I would only ever buy listed brands of those breakers - and even then I might buy two so I can drill it out and see that it actually has arc chutes in it and moving parts

 

[efficientPV]

There is a video out there where a guy says those are dangerous and he hooks it up backwards and it catches on fire a few minutes after he turns it off.... well duh, hook a polarized breaker up backwards and havok ensues.

It probably would have failed anyway. I don't have much confidence in breakers from China. I did some testing with DC breakers and polarity didn't matter much. One actually performed better backwards.

 

[robbob2112]

I have a number of the MCCB style from various vendors - I've taken them apart and they look like they will all do the job - over an inch of separation on the contact patch to break the arc, huge arc chutes and magnets to help extend it farther, etc... the main variation seems to be the cheaper ones use an aluminum current carrying bar and the better ones use copper. The better ones are also lubricated with grease in a number of spots.

 

[IAm_Not_Lost]

The wiring is fine and correct. Watched a million videos on this when I hooked up my system. That is how you wire it and how every other PV focused MCCB breaker works.

 

[wpns]

The wiring is fine and correct. Watched a million videos on this when I hooked up my system. That is how you wire it and how every other PV focused MCCB breaker works.

Even though the OP's markings are different, positive is always on the right in your world?

 

[IAm_Not_Lost]

Even though the OP's markings are different, positive is always on the right in your world?

Yep, you’re right. I went and looked at my MCCB’s and every other similar one I have which are all positive on the right and assumed his was the same, and didn’t look at the little diagram. My mistake.

With that said, EARU’s diagram shows the red (assumedly positive) on the right.

 

[wpns]

Yep, you’re right. I went and looked at my MCCB’s and every other similar one I have which are all positive on the right and assumed his was the same, and didn’t look at the little diagram. My mistake.

With that said, EARU’s diagram shows the red (assumedly positive) on the right.

That's the wonderful thing about standards, there are so many to choose from.

 

[Mattb4]

Yep, you’re right. I went and looked at my MCCB’s and every other similar one I have which are all positive on the right and assumed his was the same, and didn’t look at the little diagram. My mistake.

With that said, EARU’s diagram shows the red (assumedly positive) on the right.

Your image is a MCB not a MCCB

 

[Q-Dog]

Yep, you’re right. I went and looked at my MCCB’s and every other similar one I have which are all positive on the right and assumed his was the same, and didn’t look at the little diagram. My mistake.

With that said, EARU’s diagram shows the red (assumedly positive) on the right.

The diagram on the breaker shows (+) on the left. I would follow the diagram on the breaker.

Correction: I would return that one and get a brand that I trust.

 

[IAm_Not_Lost]

Your image is a MCB not a MCCB

Yeah, I’m just striking out today. Apparently need to go get some sleep.