Parallel Solark 15k, no interconnect agreement.

[zanydroid]

No auto transformers allowed.

Thanks for this info. It can't be that simple though. Do you mean no autotransformers allowed to adapt foreign hardware, or no autotransformers allowed period? It can't be the latter because there are a ton of listed hardware that use autotransformers to generate neutral when running off grid, when the UL1741+ inverters are 240V only.

 

[629658]

If you haven’t bought it yet the Pentair Intelliflo is a great pump and it sips power

 

[629658]

Thanks for this info. It can't be that simple though. Do you mean no autotransformers allowed to adapt foreign hardware, or no autotransformers allowed period? It can't be the latter because there are a ton of listed hardware that use autotransformers to generate neutral when running off grid, when the UL1741+ inverters are 240V only.

Not an electrician but I have been through this twice and there are many threads on here substantiating the fact that first if it’s not UL listed it’s a no go. Second, it has to be split phased 120/240. Auto transformers (external I’m certain no idea of the internals) are not approved to be used on utility interconnects. It will not be approved on inspection. At least here in the USA. This only applies if you are going to be connected to the grid in any way as parallel generation. Off grid completely not an issue.

 

[zanydroid]

Not an electrician but I have been through this twice and there are many threads on here substantiating the fact that first if it’s not UL listed it’s a no go. Second, it has to be split phased 120/240. Auto transformers (external I’m certain no idea of the internals) are not approved to be used on utility interconnects.

The ATs I'm talking about are part of installation instructions for listed 1741SA / CEC approved equipment.

I do agree that most of the other use cases of ATs are not going to fly for an interconnect.

 

[629658]

The ATs I'm talking about are part of installation instructions for listed 1741SA / CEC approved equipment.

I do agree that most of the other use cases of ATs are not going to fly for an interconnect.

I’d absolutely get prior approval before purchase. Inspectors can be brutal. Submit your materials list and line drawings for approval before you buy too. This stuff is too expensive to buy and install only to find out it can’t be connected. Just my opinion.

 

[629658]

Just for my own interest what auto transformer equipment are you referring to that is UL listed and California rule 21 listed that is approved for connection to the US grid?

 

[zanydroid]

I’d absolutely get prior approval before purchase. Inspectors can be brutal. Submit your materials list and line drawings for approval before you buy too. This stuff is too expensive to buy and install only to find out it can’t be connected. Just my opinion.

Yes for my current project I'm using standard equipment on CEC list, and I'm going to clear POCO interconnect pre-engineering approval before I tell AHJ to start checking. Since the latter costs me $800 + recheck fees that I'd rather minimize. And only after that place firm orders for equipment.

I was originally going to do AHJ in parallel with interconnect approval but I think that just risks extra fees in exchange for saving 3 weeks of time. Blah.

 

[zanydroid]

Just for my own interest what auto transformer equipment are you referring to that is UL listed and California rule 21 listed that is approved for connection to the US grid?

Growatt 5kW Automatic Transfer Switch & Autotransformer

DetailsGrowatt (ATS-US) Auto Transfer Switch and US Split Phase Transformer: • ATS-US comes with built-in transformer• ATS 5000T -US has a maximum sum of L1-N and L2-N simultaneous output is 5000VA

www.renvu.com

It pairs with the MIN 3-11.4K hybrid.

I didn't specifically verify that the AT is on the CEC list but the hybrid is.

Also dcbel and Enphase have ATs embedded in their equipment. You can see it on the SLD.

 

[629658]

Growatt 5kW Automatic Transfer Switch & Autotransformer

DetailsGrowatt (ATS-US) Auto Transfer Switch and US Split Phase Transformer: • ATS-US comes with built-in transformer• ATS 5000T -US has a maximum sum of L1-N and L2-N simultaneous output is 5000VA

www.renvu.com

It pairs with the MIN 3-11.4K hybrid.

I didn't specifically verify that the AT is on the CEC list but the hybrid is.

Also dcbel and Enphase have ATs embedded in their equipment. You can see it on the SLD.

Good Luck I don’t think that piece is UL Listed. Our utility is very strict about that. My next question would be if you have a UL listed Inverter it would be 120/240 split phased already why the Auto transformer? Keep us in the loop.

 

[zanydroid]

My next question would be if you have a UL listed Inverter it would be 120/240 split phased already why the Auto transformer? Keep us in the loop.

It's for a separate project I'm thinking of doing next year, not related to this grid-tie project.

I might get a single 120V UL-listed hybrid inverter rather than two (to save money / space), for emergency grid-down power. And then use an Auto-transformer to AC couple my existing microinverters to it. It's obviously not possible to directly couple these 240V microinverters onto a 120V inverter, and in grid-down situation I cannot use the utility transformer to do 240V->120V step-down from the microinverters

 

[zanydroid]

Good Luck I don’t think that piece is UL Listed

Renvu links an ETL certificate for the Autotransformer https://drive.google.com/file/d/1DNHvlpdVsh0tdVKnf4VwtyeCRhQ6IFRY/preview

Note I'm not using this AT, I just noticed it while talking to some other people about grid-tie projects in California.

 

[Ampster]

I didn't specifically verify that the AT is on the CEC

Then, I would caution anyone to be careful about relying on your earlier statement. They should do their own verification and make sure any product they propose for an installation is actually on the CEC list

 

[zanydroid]

Then, I would caution anyone to be careful about relying on your earlier statement. They should do their own verification and make sure any product they propose for an installation is actually on the CEC list

OK that makes sense.

I just scrubbed through the CEC lists pretty quickly and only the "main" unit of the Growatt system is listed, namely the hybrid. I don't see the transformer as separately listed.

And I stand by my assertion that there are UL-listed systems that have ATs. For sure the Enphase and Dcbel components with embedded AT are OK for installation in California. Note in both these systems the AT are interlocked to engage in mutual exclusion with being on-grid.

As I said I think randomly adding an AT that's not in a manufacturer's SLD is a recipe for great sadness, esp if you need the AT active when on-grid to make your system work.

 

[629658]

Good Luck I don’t think that piece is UL Listed. Our utility is very strict about that. My next question would be if you have a UL listed Inverter it would be 120/240 split phased already why the Auto transformer? Keep us in the loop.

FYI I’ve been looking at your inverter and I can not find a UL certificate and it is not on the California Solar equipment list
https://www.energy.ca.gov/programs-and-topics/programs/solar-equipment-lists so be very careful I don’t think this equipment will qualify. I could be missing something but if your inverter isn’t on the California solar equipment list it’s probably not going to be interconnect eligible.

 

[zanydroid]

FYI I’ve been looking at your inverter and I can not find a UL certificate and it is not on the California Solar equipment list
https://www.energy.ca.gov/programs-and-topics/programs/solar-equipment-lists so be very careful I don’t think this equipment will qualify. I could be missing something but if your inverter isn’t on the California solar equipment list it’s probably not going to be interconnect eligible.

Thanks for double checking. It's not for my project, someone else's on the forum actually. So I'm not really the person to talk to about that. But here is my paper trail.

CEC for the hybrid. I didn't see the Autotransformer + Automatic Transfer Switch combination, I don't know if it's listed separately.

It's possible this anyway cannot be used, if the ESS it comprises (along with the battery) is not yet CEC approved. CEC has blessed part of the system, is the only positive evidence the paper trail below indicates. The AT is interlocked away from grid power by the ATS in this device so I'm not sure its existence matters for interconnection purposes, since it cannot be paralleled with grid.



Renvu catalog

ETL UL 1741 cert for the AT

 

[zanydroid]

For MY project, I entered all hardware into the PG&E interconnection webapp by picking it from a dropdown list of equipment in the browser, which is populated solely by CEC equipment. And I submitted a custom SLD that only has components available in those dropdowns.

 

[629658]

Thanks for double checking. It's not for my project, someone else's on the forum actually. So I'm not really the person to talk to about that. But here is my paper trail.

CEC for the hybrid. I didn't see the Autotransformer + Automatic Transfer Switch combination, I don't know if it's listed separately.

It's possible this anyway cannot be used, if the ESS it comprises (along with the battery) is not yet CEC approved. CEC has blessed part of the system, is the only positive evidence the paper trail below indicates. The AT is interlocked away from grid power by the ATS in this device so I'm not sure its existence matters for interconnection purposes, since it cannot be paralleled with grid.

View attachment 139190

Renvu catalog
View attachment 139191
ETL UL 1741 cert for the AT
View attachment 139192

Is this system to be installed in the US? CEC certified won’t work in the US.

 

[zanydroid]

Is this system to be installed in the US? CEC certified won’t work in the US.

CEC = California Energy Commission (since I'm in California)

As well as some Australian entity, to my understanding. Which is irrelevant to me and confusing.

 

[629658]

For MY project, I entered all hardware into the PG&E interconnection webapp by picking it from a dropdown list of equipment in the browser, which is populated solely by CEC equipment. And I submitted a custom SLD that only has components available in those dropdowns.

so all I can say is that my interconnection application allows me to enter in any piece of equipment but it also states it must be California rule 21 compliant among other certifications which all compliant equipment is on the California Solar Equipment list. I was just looking and there are zero Growatt inverters listed unless it’s under another name.

 

[629658]

I should have said CE certification only is not acceptable.