California NEM Single Line Drawing

[skyc]

I did the attached diagram for the interconnect agreement based on some examples I have found and I'm curious how it compares to some of you that have done their own interconnect submission and if you think it will work? The sample line diagram that is an option to select as representative is also attached, which might work as well - assuming inverter can equal microinverter?

Additionally, thoughts on AC disconnects with microinverters - from what I've found, not required as the shutoff is built into the microinverters.

 

[Kuma]

Hi, I am also starting the NEM process. Did you learn what is required for a Single Line Drawing? I am hoping the first example, no detail, will suffice due to not knowing what the design and exact system size will be.

 

[Ampster]

Ultimately details will be required in the application to the utility. In the case of a building department they are used to seeing details on most plans. Therefore a detailed Single Line Diagram may be all you need for that process. In the case of a NEM process, the SLD could serve both parts of the process.

 

[Kuma]

Ultimately details will be required in the application to the utility. In the case of a building department they are used to seeing details on most plans. Therefore a detailed Single Line Diagram may be all you need for that process. In the case of a NEM process, the SLD could serve both parts of the process.

Thank you. Yes, I understand building permits will require detail and do have some experience with building dept and plan approval. When you say SLD for NEM, is that the above example with the number of panels and system size? Or the basic flow chart SLD?

 

[Ampster]

When you say SLD for NEM, is that the above example with the number of panels and system size? Or the basic flow chart SLD?

I used a third party to draw the SLD, He used the same diagram for both parts of the process and it had details. In my case there was no other way since PG&E required a copy of the building permit and confirmation of final inspection before issuing the PTO. It is best to check with your utility and building department to confirm. Your mileage may vary.

 

[skyc]

Hi, I am also starting the NEM process. Did you learn what is required for a Single Line Drawing? I am hoping the first example, no detail, will suffice due to not knowing what the design and exact system size will be.

Are you SDGE or PG&E for your provider? The first example is directly from the SDGE form, which you can select as representative of your install which I think is valid if you aren't using microinverters. I'm working on one with microinverters (starting point is the second image from my original post). But I think I am going to dumb it down for the interconnect application and leave the details for the permitting process.

 

[Kuma]

Are you SDGE or PG&E for your provider? The first example is directly from the SDGE form, which you can select as representative of your install which I think is valid if you aren't using microinverters. I'm working on one with microinverters (starting point is the second image from my original post). But I think I am going to dumb it down for the interconnect application and leave the details for the permitting process.

PGE. I found this. Not sure if its current. It is certainly dumbed down I think that the PGE online application program may provide samples. Trying to understand some things before starting an application.


https://www.cpuc.ca.gov/-/media/cpu...erter-working-group/r21-template-slds-pge.pdf

 

[cgeldert]

I did the attached diagram for the interconnect agreement based on some examples I have found and I'm curious how it compares to some of you that have done their own interconnect submission and if you think it will work? The sample line diagram that is an option to select as representative is also attached, which might work as well - assuming inverter can equal microinverter?

Additionally, thoughts on AC disconnects with microinverters - from what I've found, not required as the shutoff is built into the microinverters.
View attachment 138889

https://www.sdge.com/sites/default/files/Nem-OneLineElecDiag_0.pdf

View attachment 138887

Here is what I did. Its not the most professional but it has everything they asked for. Note that the basic SLD you are showing is not what they have as an example of the SDGE site. That drawing is in the application but they have a bit more specific example on their site. I will see if I can upload it here. I believe you are correct in that you do not need an AC disconnect.

 

[cgeldert]

I did the attached diagram for the interconnect agreement based on some examples I have found and I'm curious how it compares to some of you that have done their own interconnect submission and if you think it will work? The sample line diagram that is an option to select as representative is also attached, which might work as well - assuming inverter can equal microinverter?

Additionally, thoughts on AC disconnects with microinverters - from what I've found, not required as the shutoff is built into the microinverters.
View attachment 138889

View attachment 138887

I actually realize my drawing is lacking some stuff as well, and incorrect in some parts. With that said I went back and read the application. I do not believe the use of microinverters keeps you from using the SLD you posted. The concecpt is the same. Looking at the custom SLD I dont see how microinverters cause this to be needed: "I will submit a custom SLD for one or more of the following reasons: there is/are existing Generating Facility(ies) connected to this service, I am modifying an existing Generating Facility, or the Basic SLD does not accurately reflect the project."

 

[skyc]

@cgeldert - I think because the microinverters use the Envoy combiner box, the basic SLD might not be totally representative? Since I need a more detailed version for the permit application, I figured I would just put together something I could use for both. I found a few more examples of SLDs that had common details between them, so added them to my diagram. I have a few more columns around conduit and temperature impacts that I still need to understand and update the info. I might pull them for the application and put them back in for the permit application.

 

[cgeldert]

@cgeldert - I think because the microinverters use the Envoy combiner box, the basic SLD might not be totally representative? Since I need a more detailed version for the permit application, I figured I would just put together something I could use for both. I found a few more examples of SLDs that had common details between them, so added them to my diagram. I have a few more columns around conduit and temperature impacts that I still need to understand and update the info. I might pull them for the application and put them back in for the permit application.

Nice details. I think the only thing you would need to add is the CEC rating they ask for.

 

[skyc]

Nice details. I think the only thing you would need to add is the CEC rating they ask for.

Thanks for pointing that out, replaced one of my system summary lines with that value and I think I cover everything they list as required. I removed the conduit section for now, will figure that out when I go for the actual permit. Going to submit tomorrow, will be interesting to see how it plays out with them reviewing.

 

[Hedges]

"Standard Single Line Diagrams

PG&E has standard single line diagrams (SLDs) available to help speed you through the application process in many cases. These are provided here for your reference, but if these work for your project, they are also included and available for selection in the application portal during the application process."

https://www.pge.com/tariffs/assets/pdf/tariffbook/ELEC_FORMS_79-1151B-02.pdf

I think that should be good enough for Enphase. One line represents multiple wires. One Inverter represents multiple inverters. (many people have 1,2,3,4, but you have dozens. What's the difference?) Generator is a bunch of PV panels.

https://www.pge.com/pge_global/common/pdfs/for-our-business-partners/interconnection-renewables/SNEM-Paired-Storage-AC-Coupled.pdf

Here's what I submitted initially.
Sufficient to show how I was getting from split-phase to 3-phase. Although, they asked if I really meant to do that.
When I said yes, they said the TriPower model shown did not comply. (I had selected a compliant one in the pull-down menu because mine wasn't listed.)

So I told the to use the standard SLD and a couple Sunny Boys.



All PG&E cares about is amperages, PV backfeed breaker, inverter wattage, inverter functionality, array size, disconnect switch, and for larger systems interrupt current rating.

KISS.

 

[rezin]

My panel has no main breaker. Do I need to create a custom SLD?
Also, I'm just trying to get the application into PG&E before 4/14 (just bought an EV last week and learned about deadline a couple days ago). Any quick tips on what equipment to list? I understand changes can be made later as long as wattage is same or very similar.
Worst that can happen is that I get rejected, so it's worth trying... Thanks for any pointer!

 

[Hedges]

Simplest would be to reference their SLD.
Do you have just meter and panel with branch breakers, but no main breaker?
You might do a panel upgrade before or during PV install.

you don't have to list EV or any equipment (other than optional disconnect switch, inverter, PV panels.) Just declare how many kWh you plan to increase annual consumption, if necessary to justify larger system.

Pointers:
Complete the application using their website (after filling .pdf for practice). That ensures you select equipment with currently required features.
Your bill has an account number, but also "agreement" number and "meter" number, which are needed.

 

[zanydroid]

You may need to modify the SLD to avoid problems with this SLD not matching the one from your building permit.

Did you identify main and subpanels correctly?

File application with microinverters, those are IMO the easiest to understand. The application web form has a list.

For solar panels, I keep it simple and check what the closest distributor has. CED green tech and Renvu have warehouses around California.

There is a maximum watt decrease % as well IIRC so you can’t just randomly pick a number of solar panels, you have to be at least somewhat close.

Maximum number of solar panels and inverter capacity is determined by roof size, service size, and how much you are willing to upgrade load centers to max stuff out. There are fire access path requirements that reduce available roof area.

 

[rezin]

thanks. The panel is original from 1964, maybe anyways time for an upgrade. I might just keep the default SLD.
Yes, sketching panel patterns for roof right now.
Yes, this is the main panel. It does have a 100 Amp breaker for sub-panel.
Application form asks for amperage of panel... as I don't have a main breaker, how do I know?

 

[Hedges]

If it happens to be Zinsco, you do want to replace it.
The panel may have a sticker with amperage somewhere.
So it has several branch breakers, including the 100A one?

Are you putting in 7.7kW of PV with 40A breaker, or 3.8kW of PV with 20A breaker?
Those would generally require 200A or 100A main panel, respectively.

Hope your PV breaker is on main panel. If it is on sub-panel, then that 100A breaker is considered PV breaker for 120% rule calculation for main panel.

 

[zanydroid]

Safest to assume 100A and to backfeed solar into the subpanel. That is what I did with my main without main breaker. Do not backfeed solar into that main even with extra spaces. Absence of busbar rating and main breaker will cause a lot of drama around getting plans approved / being safe.

100A to Subpanel is no issue, I have one PTO project at my house with this exact situation. And one at interconnect application queue, same house, bringing total solar to 18kW range

Upgraded subpanel to 225A bus, kept the 100A feeder for now since the underground service will be a huge $$$$$$$ to upgrade.

 

[zanydroid]

Hope your PV breaker is on main panel. If it is on sub-panel, then that 100A breaker is considered PV breaker for 120% rule calculation for main panel.

It’s better to feed onto subpanel. 100A breaker for sum of breakers rule on 100A busbar passes.

EDIT: For sum of breakers you add up all load/power source breakers and it needs to be lower than busbar. Main breaker is excluded from calculation.

I convinced a designer on each of my two phases of solar install to do that. First one is PTO.

And then subpanel upgraded to 225A bus can accept a 100A PV breaker.