DIY installation - Final Steps - Solar system off while waiting for approval

[Radix]

I am in the final step of installing the components on the wall. Found an Electrician who is familiar with Solar but not a solar installer, so my concern is he will install as he figures will work. I am more concerned now with how it will work to have the PV system off and still run on grid until approved.

I was told I needed a sub panel in case Grid goes down, otherwise Solark will not run either, but as I understand, the current main panel would be emptied of all breakers and used in subpanel, so subpanel is obsoleted.

The Main Panel is a combo Meter/main Panel, to avoid running a secondary panel, the thought is run from Meter -> AC Disconnect ->Solark15K -> back to main breaker panel. Electrician said this will work, asking a buddy of his that has done solar installs before.

My concern is will I be without power until city and PGE approves because panel is tied only to Solark, or can the Solark be on, but just Panels/ PV generation turned off/ disconnected via the Solark Controller?

I am still confused on the subpanel requirement to keep running in a Grid down scenario, but concerned with my approach will leave me powerless until city and PGE approves to turn on. Look through youtube videos but all really only talk of adding panel to power their garage not tied in as a whole house source.

Electrician is supposed to be available next weekend or following, so I have a week or two to source another panel if needed.

Id appreciate any help or knowledge so I am not without power for taking the DIY route.

Thanks

 

[robbob2112]

Have you read the install guide? It has a bunch of different diagrams how to wire it in. You need a bypass panel with breakers to energize the new load panel. It will be a 2 blade double sided box with break before make connections... so middle feeds the new panel, the gird on the top and solar on the bottom. The other option might be a breaker interlock panel so only one input can be on at a time. There are several ways to do it.

 

[Radix]

Have you read the install guide? It has a bunch of different diagrams how to wire it in. You need a bypass panel with breakers to energize the new load panel. It will be a 2 blade double sided box with break before make connections... so middle feeds the new panel, the gird on the top and solar on the bottom. The other option might be a breaker interlock panel so only one input can be on at a time. There are several ways to do it.

Thanks, I have looked at the manual, and as you stated it shows different diagrams but does not specify what each diagram is specific to what someone is trying to do, at least not to someone that is not familiar with it until it is taught. The diagrams to me as as helpful as someone saying you need a subpanel, which because I don’t understand it does not make sense to me, if my expectations, is that when grid prices down, you won’t notice it in the home, but a subpanel with less circuits limits what is energized in the house.

As I understand, and diagrams I’ve seen in this group, a subpanel will only be to power critical units or circuits, but not all the same circuits as the current main panel?

I figure I am getting solar to not pay the utility high rates, but also, if power grid is down, nothing changes for me while in the day or at night with a battery inside the house.

So to me, it makes sense to power the original panel from the inverter so solar is providing power to the whole house as the grid would.

I am missing/not understanding something that everyone seems to know.
And just someone saying you need a subpanel does not make sense to me.

That is why I am here asking for help.

If I have to get a subpanel, it’s fine, but I would think I want one to energize the same circuits as current, but also as mentioned to me, can reuse all current breaker in main panel if n new one, then that tells me old panel is obsolete…

If anyone has any diagram, video, article that explains the flow for this that would be great.

 

[robbob2112]

Sorry, from the original question I didn't think you had looked at it.

What you need is a bypass or transfer switch between grid and the main panel. This will be used when the solark is off to provide power to the main panel.

@Hedges is the King of explaining this sort of thing. If he doesn't chime in you can search under his username or I can look. He has answered this question before.

 

[Radix]

Sorry, from the original question I didn't think you had looked at it.

What you need is a bypass or transfer switch between grid and the main panel. This will be used when the solark is off to provide power to the main panel.

@Hedges is the King of explaining this sort of thing. If he doesn't chime in you can search under his username or I can look. He has answered this question before.

Thank you, I’ll search for his posts

 

[Hedges]

So your installer thinks he will be able to run wires from the meter over to a (fusible) disconnect? Depends on how your combo meter main panel is constructed. He would have the meter yanked to cut power while doing that work.

I always want a breaker panel to have a way to connect to grid if inverter fails. An interlock between main breaker and a backfed "generator" breaker can be used. For my QO series panels, 125A is the largest branch breaker I can get that the interlock is meant to work with. They do have a 4-pole breaker for 200A, but the handle doesn't match up to interlock. Homeline series I think 200A could work.

Post in thread 'Manual disconnects'

Jul 1, 2024

To switch between two sources feeding a sub-panel, I used an interlock and backfed "generator" breaker.

Search Results for generator interlock at The Home Depot

Search Results for generator interlock at The Home Depot

www.homedepot.com

With a main breaker installed, as Hwy17 said.

• Hedges

 

[Radix]

So your installer thinks he will be able to run wires from the meter over to a (fusible) disconnect? Depends on how your combo meter main panel is constructed. He would have the meter yanked to cut power while doing that work.

I always want a breaker panel to have a way to connect to grid if inverter fails. An interlock between main breaker and a backfed "generator" breaker can be used. For my QO series panels, 125A is the largest branch breaker I can get that the interlock is meant to work with. They do have a 4-pole breaker for 200A, but the handle doesn't match up to interlock. Homeline series I think 200A could work.

Post in thread 'Manual disconnects'

Jul 1, 2024

To switch between two sources feeding a sub-panel, I used an interlock and backfed "generator" breaker.

Search Results for generator interlock at The Home Depot

Search Results for generator interlock at The Home Depot

www.homedepot.com

With a main breaker installed, as Hwy17 said.

• Hedges

I

I am a visual learner, is there a good diagram that explain how the power flows to explain this. I don’t understand how the whole system goes down if the grid is down. Is t that the purpose of the solar system with battery backup?

 

[Radix]

I am a visual learner, is there a good diagram that explain how the power flows to explain this. I don’t understand how the whole system goes down if the grid is down. Is t that the purpose of the solar system with battery backup?

I saw this diagram someone else posted here, but it shows a subpanel for critical system, how does this need to be so the whole house runs on solar. I know this sounds trivial to mostly everyone here. But for me it seems I run off subpanel or main panel, but not both, correct?

 

[Radix]

I saw this diagram someone else posted here, but it shows a subpanel for critical system, how does this need to be so the whole house runs on solar. I know this sounds trivial to mostly everyone here. But for me it seems I run off subpanel or main panel, but not both, correct?

So looking at the diagram and the solark manual, when the subpanel is installed the critical connections need to be ran to the subpanel. The full disconnect from grid is a safety thing, read that online and make sense.
I see the comment about electrician may not be able to run power from meter to solark directly without utility shutting down power all together and or removing meter.
So this means there is no way to do this without adding a subpanel and in the end only some circuits would be tied to subpanel, unless all connections are ran to new subpanel.

Is that correct?

I filed permits and drawing right before NEM3 deadline, the subpanel was not the plan, since I just paid someone to else to build the plan set and that was not a question for the line drawing. I am banking on the “homeowner leniency” the city gives when homeowner does the “work”, but if in the end I have to re-file and loose the NEM2 then I guess that is how it will be, or could make the change after it passes inspection.

 

[Hedges]

You want NEM2.
All PG&E cares about is wattage of inverter and of PV panels. (and maybe efficiency and CEC ratings; calculated nominal power to be delivered.)
If you change wiring of boxes downstream of service disconnect, that doesn't matter to them so long as you have whatever disconnect preventing backfeed that you documented, and that is probably flexible.

Me, I did NEM2 reservation then I did service upgrade (100A --> 200A) request, then installed service upgrade, now working on PV.

Note in SolArk's diagram they provide OCP between meter and SolArk. That is because SolArk does not have a built-in breaker on input. It does have one for output.

If your electrician can wire fused disconnect and SolArk after meter and before existing 200A breaker service disconnect, that works. To do it depends on there being wire in lugs that he can re-route; some boxes I've seen have flat busbars there.

I prefer meter connects to 200A breaker for service disconnect, then wires feeding main loads panel (I add a main breaker there) and also fused disconnect.

What you've described can be done with just the 200A main panel, no other sub panel.
The problem with it is, if SolArk can't deliver enough power for all active loads (e.g. electric furnace + electric dryer + electric oven + EV charger), then when grid goes down, SolArk shuts off due to overload and you have no power.

That's why, to me, it makes more sense to have a 200A main panel fed from the grid, and a panel backed up by SolArk that never has more loads than SolArk can handle. Plus interlocked backfed breaker in 200A main panel so you can shut off excessive loads then transfer remaining loads to SolArk.

If SolArk fails, do you have a way to turn power back on?
I have grid feeding inverter feeds backed up loads panel,
plus grid also feeds backed up loads panel, through an interlocked breaker.
I would rather it was automatic transfer switch, so if inverter fails while I'm away the freezers keep working.
Possibly SolArk defaults to relay closed when inverter off, solving that for you. In my case, default is relay open.

 

[Radix]

This part of is confusing to me and maybe I takes things literally and missing electrical common knowledge details.

Pg7 of the 15K manual reads 200A for LOAD, GRID and LOAD breaker. That is the current size of the main panel. If I was regularly overloading more than 200A would my main main breaker be popping regularly?

This thought process is what make me believe it shouldn’t be a problem, but again, seems I am missing some electrical common knowledge details.

 

[robbob2112]

The issue is a single Sol-Ark 15k can only provide a maximum of 62.5amps at the most. It puts out 50 amps from battery and 12.5 amps from solar of AC voltage. If your loads at the time grid power dies are higher than that it may run a short while in surge capacity but it may also trigger overload and shutdown right away.

To fully replace 100% of a 200amp service it takes 4 of the 15k units in parallel. It is a good thing most households use far less than that. For all the non-heavy draw items - i.e. no AC, electric heat, dryer, electric cooktop, etc you are generally only consuming 20~30 amps max. If you have all LED lights and run nothing special your total load can be far far less.

So what he is saying is a critical loads panel runs the fridge, freezer, lights, and non-high current loads and when the grid is out those loads go unpowered.

The 200amp figure you are reading in the manual is how much capacity it can pass through and augment. So if you have 1 Sol-Ark and your demand is below 62.5 amps in the day your grid draw will be zero. If you are running the AC on high and the double oven and a cooktop your draw may be 100+ amps and the inverter can supply the first 62.5 amps, the rest comes from the grid.

 

[Radix]

Ok, I see the 62.5A output on the 15k datasheet now.
I have an emporia logger installed and can see, at least per minute totals, the max Amp in every circuit. I could technically just not run the dryer and AC and would be below the 15K max. Knowing Grid is down manage what is turned on and when as well. So looks like a subpanel is needed after all, but if Hedges is correct and PGE and City will not care of anything after the AC disconnect, then I can add one still and remain in NEM2

 

[robbob2112]

Ok, I see the 62.5A output on the 15k datasheet now.
I have an emporia logger installed and can see, at least per minute totals, the max Amp in every circuit. I could technically just not run the dryer and AC and would be below the 15K max. Knowing Grid is down manage what is turned on and when as well. So looks like a subpanel is needed after all, but if Hedges is correct and PGE and City will not care of anything after the AC disconnect, then I can add one still and remain in NEM2

I would think you can - they will still want a 1-line drawing for the actual changes to electrical system for the house when the permit is drawn - so may as well put in a correct one. And the electrical inspector will look at the whole system.

The power company doesn't care what you have behind the meter - only the in and out part - but they will look over the install as well, just not likely to do it in depth. So long as that doesn't change there shouldn't be any issue with NEM2

 

[zanydroid]

Great advice here. How much time do you have left to install NEM2? There is a deadline with PG&E. Some AHJ also have a deadline wrt how long a permit can be open. Make sure you are aware of this and time box your iteration. At some point you may want to just final out and PTO with whatever ruthless shortcuts are needed, then polish the turd more afterward on a second permit

 

[Hedges]

Under NEM, it may be useful to have PTO late in winter, so you end the annual true-up after a few months of net consumption not in summer with net production.

Because I have a choice between gas and electric heat, I can switch off electric heat to avoid blowing through surplus and owing money at true-up.

"To retain NEM2 eligibility, final electrical clearance (final building permit) must be submitted before April 15, 2026

Upload all page(s) of the final signed-off permit (and permit application, if applicable) as one PDF file, showing that the Generating Facility has received final approval by the local authority having jurisdiction and the date such approval was given"

In Oakland, permit expires if 6 months goes by without requesting an inspection (so I just did one.)

Maybe if SolArk has a status output "on grid", you can send that to a load-shed relay for the dryer, maybe just L1 or L2 if that only goes to heating element.
Also have it alert you, as battery SoC you may want to manage.

 

[zanydroid]

Under NEM, it may be useful to have PTO late in winter, so you end the annual true-up after a few months of net consumption not in summer with net production.

This only affects the first year though. I guess that’s a couple percent $ wise.

 

[Hedges]

No every year. If true-up comes in August, you don't know in March if you should use electric heat or gas. Can't predict or control summer production.

If true-up comes April 1st, you can vary consumption the last few months by selecting gas vs. electric heat (if so provisioned.)

Now if you have EV + ICE or plug-in hybrid, then you can make that choice in the summer for an August true-up.
What I could do is filter pool less (trade off for more chlorine, maybe?)

 

[Radix]

No every year. If true-up comes in August, you don't know in March if you should use electric heat or gas. Can't predict or control summer production.

If true-up comes April 1st, you can vary consumption the last few months by selecting gas vs. electric heat (if so provisioned.)

Now if you have EV + ICE or plug-in hybrid, then you can make that choice in the summer for an August true-up.
What I could do is filter pool less (trade off for more chlorine, maybe?)

I am hoping to switch out the AC/central air for a Heat pump. This will be after batteries, most likely in January or a month after pass inspection.

On my original questions, I will be adding the subpanel, and I am guessing if I want to be able to use grid power while waiting for inspection, the Switch is needed so I can run on Grid while "technically" solar is not permitted to run until it passes inspection.
Or is there another way to keep the house with power while Solar system is off waiting for PGE and the city?

 

[Hedges]

If you have battery, you can run some or all of the house while disconnected from grid.
Maybe inverter can also charge batteries from grid if they get low, in addition to PV. Not sure how yours operates to prevent backfeed.

A transfer switch or interlocked breaker will let your sub-panel be connected to grid and isolated from inverter, or vice versa. That allows testing and operating prior to utility PTO.

 

[Radix]

If you have battery, you can run some or all of the house while disconnected from grid.
Maybe inverter can also charge batteries from grid if they get low, in addition to PV. Not sure how yours operates to prevent backfeed.

A transfer switch or interlocked breaker will let your sub-panel be connected to grid and isolated from inverter, or vice versa. That allows testing and operating prior to utility PTO.

I will have batteries, just not yet, since not in the original permit submission, do not want to trigger a refile with PGE and loose NEM2, so plan is to install them after passing inspection.

As far as I know, the Solark has the option to not feed the Grid, so can run without grid, but that will be a problem when there is not sun and need the grid, with not batteries installed yet.

So a Transfer switch will help me keep running while PV is not generating until allowed by city and PGE?

One Leg to grid only, the other Leg Grid and PV feeding the subpanel

AC disconnect should keep Solark separated from Grid as well.

I guess I am not sure if as long as the PV is not feeding back to the grid if the PV can stay on generating while waiting for the permitting and blessing to connect to grid or it needs to inverter needs to be physically turned OFF and City and or PGE will allow to switch to on when they allow it.

 

[Hedges]

Sub-panel with interlock between Main (grid) and Generator (inverter) takes care of keeping the lights on prior to PTO.

Inverter with PV but no batteries or loads would want to backfeed grid if so configured. AC disconnect on inverter's grid input prevents that.

What would almost work is configuring inverter for zero export and passing grid through it to loads. Problem is spurious export during load dump, when inverter was supplying a heavy load that suddenly shuts off. So don't turn on breakers for path to & through inverter until PG&E approves.

If we get a power failure in the mean time, you may be able to do batteryless backup. Try it out and see, will be useful prior to buying batteries.

 

[zanydroid]

One Leg to grid only, the other Leg Grid and PV feeding the subpanel

Can you clarify what you mean by leg? Because some definitions of leg are scary

 

[zanydroid]

It’s not worth trying to use a battery less system in the absence of PTO as science learning / performance art. You will also have to learn the risk of operating in parallel, and whether you have configured the system to either comply or minimize the risk of doing something bad.

IE if you just want to save money or something and don’t have any mental win from getting in the weeds, why bother.

It’s a lot better to put the time into pushing it through closing the permit and getting PTO

 

[goldserve]

@Radix where do you stand now on your install. The best is to plan out the solar install on your roof, get a permit for the solar install and do the install in this order.

Install all the solar racking, panels and DC run up to where the Solark will be. Plan out where to put the bypass switch, Solark and schedule a date with PGE to pull meter. Do the transfer switch, Solark install, reroute to main panel and finish connecting DC array with RSD to Solark. Ask inspector to come back for inspections the next day so you can get your green tag for PGE to energize your meter. Since the permit is a solar install, hopefully you would have passed with the AHJ and then you submit to PGE for PTO. In the meanwhile, you can set Solark to zero-export and if you do accidentally export back to grid, IMHO it is okay because PGE will see you have a solar install application with them and you might run the risk of paying for exported Wh but unlikely. Since you don't have battery as buffer (you could temp install some actually since you already passed AHJ inspection) and run off-grid to make sure no exports are seen by PGE before PTO.

my 2 cents.