Micro inverters at the edge of array or deep inside the array

[agarg]

Originally I laid them out but now I just hang them up on a rod.

I have to confess. It is out of the box thinking and innovative. One will have bunch of thick but low voltage dc cables going to readily reachable micros! Cheers!

 

[peakbagger]

I have similar setup. My original grid tied array was early in the grid tied game with 4 - 165 watt panels and a 1000 watt 12volt inverter. Someone at the time gave me a bunch of #8 wires so I home ran all the panels to junction box in my basement. The inverter made it 18 years and died. I wanted to keep the 4 panel running so I picked up 4 used enphase 215s on fleabay. I installed them down in the basement next to the junction box. I mounted mine on unistrut with the extra trunk cables tie wrapped up neatly. No electrical inspection in my town so I consider the inverter replacement as a "replacement in kind" so no worry about RSD. I can see the LEDs on the microinverter so no need for remote monitoring.

BTW, the Tesla solar roof fires were reportedly not MC4 connector issues as much as non MC-4 connectors made by other firms that are close to MC4 but not exactly a duplicate. I have seen MC-4 clones that sllde togehter but the tangs do not lock. Unfortunately a lot of the details are locked up under confidentiality agreements as part of the litigation.

 

[zanydroid]

My understanding of code for ground level micros is:

• panel level RSD needed for system voltage since Voc > 30V even with smallest residential panels
• MC or metal conduit needed since Voc > 30V
• AFCI not needed - Voc < 80V to ground even with monster panels
• GFP - unclear. Microinverter will still shut down but there might be a code carveout for microinverters that you violate. ~40-50Voc and available fault current might not be able to kill you anyway
• Follow manufacturer instructions - unclear. Probably up to AHJ interpretation

 

[zanydroid]

BTW, the Tesla solar roof fires were reportedly not MC4 connector issues as much as non MC-4 connectors made by other firms that are close to MC4 but not exactly a duplicate. I have seen MC-4 clones that sllde togehter but the tangs do not lock. Unfortunately a lot of the details are locked up under confidentiality agreements as part of the litigation.

AFAIK the various MC4-like vendors do not commonly do cross vendor testing internally or as submitted to UL, so this was specifically called out in the relevant update to NEC that mandates either same-brand MC4 OR MC4 listed for cross-brand compatibility.

 

[agarg]

BTW, the Tesla solar roof fires were reportedly not MC4 connector issues as much as non MC-4 connectors made by other firms that are close to MC4 but not exactly a duplicate. I have seen MC-4 clones that sllde togehter but the tangs do not lock. Unfortunately a lot of the details are locked up under confidentiality agreements as part of the litigation.

The MC4 to MC4 clones mating is an interesting topic. Many compatibles like the one from Betteri or from Tlian are top quality. Tlian certified their T4 with MC4 as you can see many places on the web and also here.

My NEP inverters came with DC connectors from Batteri and they were not certified. So I had a few choices:

1. Ignore risk and mate the Betteri and Tlian.
2. Build pig tails with Batteri at one end and Tlian at the other end.
3. Replace the Tlian on the module with Batteri
4. Replace the Batteri on the inverter with Tlian.

I came close to opting for number 1 but I thought they have to stay mated for 20 plus years and I would be very old later on to change. In addition, this was a smaller expense. The expert who does a remarkable job of crimping properly was unable to come to my home and so shipping the modules to him was out of question. In addition, the Batteri DC connectors were not very commonly stocked at many places compared to Tlian DC connectors. That made pig tails also harder.

I went with option 4. Snapped off the Batteri DC connectors and installed original Tlian connectors on the micro inverters.

And yes, there are also counterfeit DC connectors on amazon but I wasn't going there unless they came from Tyco or Tlian or Batteri... and the likes.

 

[agarg]

MC or metal conduit needed since Voc > 30V

Somehow, I thought it was 48v DC.

 

[zanydroid]

Somehow, I thought it was 48v DC.

This is a specific clause for PV DC circuits

 

[agarg]

This is a specific clause for PV DC circuits

You are so well informed, chief.

 

[kundip]

My understanding of code for ground level micros is:

• panel level RSD needed for system voltage since Voc > 30V even with smallest residential panels
• MC or metal conduit needed since Voc > 30V
• AFCI not needed - Voc < 80V to ground even with monster panels
• GFP - unclear. Microinverter will still shut down but there might be a code carveout for microinverters that you violate. ~40-50Voc and available fault current might not be able to kill you anyway
• Follow manufacturer instructions - unclear. Probably up to AHJ interpretation

Thanks for this:
In Australia metal conduit is not required only rigid PVC is required.

 

[agarg]

Perhaps this may be common knowledge for all and I learned something new. If the sky is fully overcast for a long time, the orientation of the module makes no difference. They all make similar (and, yes lower) amount of energy. Today is bright and sunny. The four modules facing the southeast were more productive early this morning than the 20 modules facing southwest!

 

[zanydroid]

Yeah, there are a lot of weird things that can happen with clouds. For instance if it is a partly cloudy day and you get direct sun through a hole in the clouds, if the hole has the right geometry you will get bonus light scattering off the side of clouds, that otherwise will not go to you.