Midnite Solar Combiner driving me NUTS

[solarstuff]

Okay this is crazy...I'm doing something wrong or are all my circuit breakers stupidly designed.

When I screw my 6 awg PV positive cables in to the Midnite Solar mnpv-6 THEY FALL OUT!

The top of the circuit breaker has a bus bar that fits inside the steel ring when you tighten the screw to hold in the bus bar.

I've tried to screw the wired in the bottom of the breakers the same way. They always fall out with the slightest tug.

Am I supposed to do something different? Bend the wire strands over the screw directly? Arg!

Happy to wear a dunce cap if someone can set me straight. Going NUTS.

 

[Bob B]

Try loosing them all the way up first .... then put the wire in and tighten.

 

[solarstuff]

Try loosing them all the way up first .... then put the wire in and tighten.

Thanks for making me feel not stupid Bob (grin) I was sure you were going to tell me something obvious I was missing,!

Hoe much tension should the circuit breaker be able to hold the wire with?

My invert has no probs with the other end of the cable...but this combiner box with the metal bracket screwed down tight with the wire between it and the pad attached to the screw just let's go with the lightest tug!

Maybe I will stiff it in and screw it down and screw a wire guide just below the box to the wall so there's no way for it to fall out.

 

[Bob B]

I have seen screw connections where it is possible to get the wire on the wrong side of the mechanism that puts pressure on the wire .... so, when you tighten it down .... nothing happens.
Thats's why I recommended having it completely loosened up first ... then it's impossible to put the wire on the wrong side.

It's possible this doesn't apply to the type of connectors you have.

 

[solarstuff]

I have seen screw connections where it is possible to get the wire on the wrong side of the mechanism that puts pressure on the wire .... so, when you tighten it down .... nothing happens.
Thats's why I recommended having it completely loosened up first ... then it's impossible to put the wire on the wrong side.

It's possible this doesn't apply to the type of connectors you have.

Will give it another college try thx Bob

 

[OffGridInTheCity]

These breakers have a U shaped 'thing' for the wires to insert into. You can miss it if you just sort of stick the wire in...
Suggest removing the top buss plate - pull out the breaker and stick in the bottom wires while looking. They will tighten down

Then snap the breaker back on the DIN rail... they'll wiggle a bit left and right to get them positioned for the cover.

 

[Bob B]

These breakers have a U shaped 'thing' for the wires to insert into. You can miss it if you just sort of stick the wire in...
Suggest removing the top buss plate - pull out the breaker and stick in the bottom wires while looking. They will tighten down

Then snap the breaker back on the DIN rail... they'll wiggle a bit left and right to get them positioned for the cover.

Yep ... that's what I was explaining ... if you loosen the connection ALL the way up, you won't get the wire on the wrong side of that U shaped "thing"

 

[rhino]

I assume you figured it out.. but for anyone else looking in future (the U shape thingy :

 

[solarstuff]

I assume you figured it out.. but for anyone else looking in future (the U shape thingy :
View attachment 61307

That's not the issue actually: the issue is the bar, fully screwed tight over the plate, is still loose enough a gentle tug can pull the cables free

I'm going to screw in cable fasteners to ensure against any accidental tugs but I'm really disappointed in the reliability of these midnite solar circuit breakers.

 

[Bob B]

If you aren't getting a tight connection .... don't use them.
The connections will build up heat and be a fire risk.

You should not be able to pull them out with a gentle tug on the wire!

 

[Dr. Dickie]

Yep ... that's what I was explaining ... if you loosen the connection ALL the way up, you won't get the wire on the wrong side of that U shaped "thing"

That is not always true. Can't remember the Midnite solar breakers exactly (I had to no problem with them), but I know that some breakers I have used when you loosen the screw all the way, the little U in there flops around. So, you can still get it behind the U.

 

[Dr. Dickie]

That's not the issue actually: the issue is the bar, fully screwed tight over the plate, is still loose enough a gentle tug can pull the cables free

I'm going to screw in cable fasteners to ensure against any accidental tugs but I'm really disappointed in the reliability of these midnite solar circuit breakers.

Something is wrong. I have the Midnite combiner box and used the Midnite breakers and they locked down as tight as any breaker I have used. Can you take a pic with the wire in? Put the wire into the bottom before you attach the top to the combiner bar.

 

[Bob B]

Something is wrong. I have the Midnite combiner box and used the Midnite breakers and they locked down as tight as any breaker I have used. Can you take a pic with the wire in? Put the wire into the bottom before you attach the top to the combiner bar.

I agree ..... I would have thought by now he would understand and be able to make sure the wire is inserted correctly .... If he can't resolve that, he shouldn't go ahead and use them anyway.

 

[rhino]

I have 4 of their combiners and there is no looseness to any of the connections including breaker to the positive busbar so I am not sure what the issue is you are having.. are you able to have a picture of what it looks like when you are able to gently pull on it and it come off? Otherwise I might try taking pic of one of mine (not sure if camera can angle in there for the shot).

 

[rhino]

the issue is the bar, fully screwed tight over the plate, is still loose enough a gentle tug can pull the cables free

Just to be clear about this, the wire is connected through the bottom of the breaker all by itself in one of those U shaped metal clips as everyone has pointed out and the breaker is firmly attached to the DIN rail in the box with one of the positive busbars fingers inserted into top of breaker.. so it is impossible to move the breaker or pull on busbar.. so only potential issue would be wire connected to bottom of breaker and that has ridges within that U shaped clipped that would be pretty difficult to pull out if properly tightened and using stranded PV wire.

 

[Bob B]

Could it be the size of wire being used? Maybe it is too small. Have you tried stripping off more wire and doubling or tripling in back on itself?

Does someone have a link to this device?

 

[rhino]

Does someone have a link to this device?

https://www.midnitesolar.com/pdfs/MNPV3_6_REV-H_10-010-1__manual.pdf

 

[Dr. Dickie]

Could it be the size of wire being used? Maybe it is too small. Have you tried stripping off more wire and doubling or tripling in back on itself?

Does someone have a link to this device?

He said they were 6 AWG, Can't be the wire too small.

 

[Bob B]

He said they were 6 AWG, Can't be the wire too small.

Yeah .... looks like it should be good down to 10 gauge.

@rhino .... Thanks for the link to the manual.

 

[740GLE]

My only thought is he didn’t strip enough insulation off and can’t bottom out the conductor in the breaker before tighten down.