EMT for DC PV inside the house. Why?

[MajicDiver]

How would a breaker trip though is the problem. Like for my string of 8 Qcells 480w, the MPP current is 10.59 amps, and the short circuit current is 11.58 amps.

I guess it’s kind of a unintended advantage of over paneling. My inverters are 13.5 amp max usable current for each MPPT, max short circuit current 16.5 amps. I’m using strings that are around 18.66 Imp and Isc about 19.6 amps. The 16 amp breakers I’m using should trip if a short circuit occurs.

 

[MajicDiver]

Yup. I'll pull the wires and do it right. I just hate to go back, as a matter of principle. In this case, the time to kludge it is only a bit less time than doing in correctly. I

I made the same mistake as you. I spent my time in the fall pulling out what I had and replaced with EMT and raceway . Put breaker box on outside basement wall for transition, now I have breakers at the pole mounts and at entry to house.

 

[hwy17]

I guess it’s kind of an unintended advantage of over paneling. My inverters are 13.5 amp max usable current for each MPPT, max short circuit current 16.5 amps. I’m using strings that are around 18.66 Imp and Isc about 19.6 amps. The 16 amp breakers I’m using should trip if a short circuit occurs.

Oh now that is very interesting. I'm planning to get into some serious over paneling eventually and I've been rolling around a thought about whether it could allow for smaller conductor sizing. E.g. could 33 amps of panels be ran over the long distance on 10 or 12 awg wire if the CC is never expected to draw over 15. OCP could guarantee it.

What I've been uncertain about is if the MPPT will get lost in it's searching sometimes and find some weird low voltage max amperage power point. But you must not find that if your fuse never blows.

 

[robbob2112]

Me neither, now that I've learned more about the reason. I just wish that I had done it right the first time. Living and learning with 480 vDC is going to kill me one of these days. Maybe that is why my wife lets me play with this stuff so much?!

Does she have a good insurance policy out on you? Or do you have a policy on you? Maybe don't let her know or you could start hearing "go play with the power some more... make sure to stand in a puddle while you do it!

 

[MajicDiver]

What I've been uncertain about is if the MPPT will get lost in it's searching sometimes and find some weird low voltage max amperage power point. But you must not find that if your fuse never blows.

On sunny days the current just ramps up to 13.5 amps and stops. On solar assistant I’ve seen spikes up to 14 amps of a couple of seconds, no spikes on the Growatt app but that just has a data point each 5 minutes. not 100% certain if the occasional spike on solar assistant is real or noise.
I’m not using fuses. I have one string that the breaker trips on every 4 or 5 weeks. Plan to replace it and see if it stops.

 

[Ronnie B]

Pull the pipe with the pv10 wires and put it through someplace else. Or pull the pipe and then feed it through from the other end.

And, Scott wouldn't have done it that way in the first place. He would have beamed the pipe into place.

Pull the pipe with the pv10 wires and put it through someplace else. Or pull the pipe and then feed it through from the other end.

And, Scotty wouldn't have done it that way in the first place. He would have beamed the pipe into place.

Scotty would enclose it in a airtight space and pulled a vacuum on it. Same as you would with dilithium crystals.

 

[MajicDiver]

E.g. could 33 amps of panels be ran over the long distance on 10 or 12 awg wire if the CC is never expected to draw over 15. OCP could guarantee it.

I don’t believe there is anything wrong with that concept.

 

[hwy17]

I don’t believe there is anything wrong with that concept.

For now I'm mostly just trying to calm myself that my 3/4 conduit I buried will be enough lol. I got anxiety that I should've gone bigger after I buried it. First single string goes up this summer, then beyond that, I'd like to start over paneling around a 100 maybe eventually 200 amp 48v output.

 

[John Schmidt]

I guess it’s kind of a unintended advantage of over paneling. My inverters are 13.5 amp max usable current for each MPPT, max short circuit current 16.5 amps. I’m using strings that are around 18.66 Imp and Isc about 19.6 amps. The 16 amp breakers I’m using should trip if a short circuit occurs.

Nice design. Makes 100% sense, now that I've seen it written! I'll remember that next time. Learning all the time. Thank-you!

 

[robbob2112]

Nice design. Makes 100% sense, now that I've seen it written! I'll remember that next time. Learning all the time. Thank-you!

Great, another topic to deep dive while planning - over paneling

 

[MajicDiver]

Great, another topic to deep dive while planning - over paneling

It’s been discussed at length in many threads, if you haven’t seen them should be easy to find. Of course, there are those who are against it, but I suggest just looking at the reasons pro & con

 

[JoeHam]

Feel no shame. My temp setup, got sick of taking the batteries outside every day to charge.

View attachment 206588

View attachment 206589

If that water bottle is not UL listed your AHJ will never approve the install.

 

[Ampster]

It’s been discussed at length in many threads....,

It is sometimes discussed as a DC to AC ratio. The higher the ratio, the more over paneling there is.