Build Your own PV Combiner

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mivey said:
Current takes ALL paths. Not just the one with least resistance. Google parallel circuits.
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Well yes i agree Mivey but i wanted to know how a wire nut takes a parallel path from two conductors inside and what the PV school teaches lets say there twisted and a good connection ?


If they were not twisted current could then take that other path by a bad connection of the wires inside thur wire nut .

Which could be a high resistance by connection current flows but thur resistance of the wire nut attached to conductors .

But then again were using a wire nut in the wrong application it was design and wires must be tighten by wire nut to work properly ?

And any lug or terminal can become the same if not tight meaning a high resistance so what do we do .

High press ?
 
iwire said:
A bit late, it took me a while to find the disc this was on.

This is a brand we use, I think we could do it better, this is expensive for what it is but it is listed as a whole.

CombinerBox.jpg
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Cutler Hammer is making combiner boxes now. I'm waiting on one now.

Is that EMT I see?
 
iwire said:
A bit late, it took me a while to find the disc this was on.

This is a brand we use, I think we could do it better, this is expensive for what it is but it is listed as a whole.

CombinerBox.jpg
Click to expand...

Well iwire nice looking work !

Question as i dont see much pv equipment but with DC whats your temp on the lugs 75 deg or 90 deg ?

And the wire to roof or cells is it rated at a higher temp ?
 
ohmhead said:
Well yes i agree Mivey but i wanted to know how a wire nut takes a parallel path from two conductors inside...
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I have no problem with a properly applied wire nut in this case and don't see why it would be an issue.
 
iwire said:
Thank you.



90C



Big time.

First to meet the requirements of 690 you add 125% twice, after that we have to apply the roof derating required in 310.15
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Well a branch of our company installs pv systems our shop has it in two builds but i would like to learn more about it just wondering what or how it works and material used is interesting to me .
 
ty said:
I don't

myth

I never said it was not acceptable, i said it is not recommended.
I agree with them.

Maybe that's it.
Poor connections add circuit resistance, increasing voltage drop, and power loss.

The whole point is the OP is questioning a combiner box.
This particular one wasn't even made in the field.
He is questioning it.
I asked for a photo and haven't seen one (of the combiner box in question)so it is hard to give an accurate opinion.
So we can only give one based on Code, which in 2008NEC there was a change.
My opinion was: If the fill size is correct, and it has rated terminal blocks, etc, etc, what's the real issue?
If it is a bowl of spaghetti, and looks like the installer didn't care, then different opinion.
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Unfortunately, I didn't get a pic of the last one I saw. And since I won't allow field built combiner's in my jurisdiction anymore without at NRTL cert I probably won't be able to get one. Thanks for all the great feedback on this.
 
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