Need some guidance before I pull the trigger

[bradley.r.zeller]

Hi all!

First post and I must start out by expressing my gratitude for this community. I’ve learned a ton in the past several weeks. Thanks!

I would love some help in designing a system for my situation. Any and all advice or comments are much appreciated!

Here’s my situation and what I’m trying to accomplish…

I have an old 3.3 kW system on my south facing roof that was installed by the previous home owner in 2009. I ran some calculations and believe they are performing at around 82%, producing around 2.7kW. I live in Southern California and get good sun year round. I’m grandfathered in to NEM 1.0 but it doesn’t really matter since my home consumes almost 100% of what my system produces (it occasionally back feeds when we’re not home during the day but negligible amounts). I believe my system offsets close to half of my energy consumption. However, I have no batteries and no resilience to power outages.

My end goal is to reduce my grid consumption / reliance down to zero (saving money) and to have uninterruptible power to my home at all times, even in a grid outage. I’d like to replace my entire existing system with a new one to accomplish these goals.

Now, I am obviously constrained by a budget so I’m trying to figure out how to iteratively build towards my end goal.

I’m feeling fairly certain that this initial investment will be for the powerpro battery, 18k pv and 14 x 380W panels.

Down the road, as I can afford, I’d like to be able to add batteries and panels if needed. But I feel good about the initial equipment getting me a solid way towards my goals.

Now, my questions!

1. The 18k manual shows a wiring diagram (4.4, attached below) for whole house backup configuration. I’m thinking this is what makes most sense for me. Since I have no interest in back-feeding the grid, would my wiring configuration be any different or the same?

2. I have an old 100A main load center + meter combo box. Do y'all think it will be possible to insert the necessary equipment (feeder tap + breaker) between the two? I was hoping I could potentially add this equipment in the attic above the panel instead of opening my exterior wall… and does it even make sense to add the feeder tap and breaker in the attic? Or do they need to be accessible? Or do you think I’m going to need a new panel with a new (separate) meter?

3. What is the PV interactive system 2 pole fused disconnect? And do I need this if I’m not exporting to grid?

4. I’m planning on using my existing roof rail to mount the new panels. Any concerns there or are these racking rails pretty universal?

5. Permitting - I’m a bit surprised I don’t see this topic talked about much on the community. I know it varies so much by location but I was wondering if a system like this typically requires permits or not. Again, I’m not exporting to the grid so maybe that plays a role in whether or not I need to get permits. I’d honestly prefer to get this system permitted for the sake of checking my work but it’s an intimidating path to go down because of the extra money and slowness of the whole process. Any guidance here?

6. I did talk to building and safety in my city and they told me that I’d need a single line diagram showing my system. Do you think the manual’s diagram below would suffice as that diagram? I could modify to remove a few things that are irrelevant but for the most part, that seems like it could work.

7. I’m also considering the 6000XP due to its affordability. I don’t believe the 6000W output would be too much of an issue in my case and I believe this system will switch to grid in the case the load exceeds 6000W, right? I also don’t think the 8kW solar input is a limitation in my case. However it does seem like the 18k has more features that would be helpful for accomplishing my goals… or are these two inverters more similar in features than I think?

8. I see in the diagrams that the ct sensors need to go as close to the meter as possible. However, in some of Will’s videos, he has the ct sensors in the inverter wiring bay on the AC in wires… that seems much simpler than getting them into the meter box. Will this work? Or why do they need to be close to the meter?

9. Any other advice for my situation?!

Thank you community!

 

[12VoltInstalls]

have no interest in back-feeding the grid

Leave the existing backfeed systems running…

they need to be accessible

accessible is defined in NEC

Any other advice for my situation

i myself would leave the existing services in place, and run a new panel to feed from your backup power system that will switch to off grid-side anyway if grid is down.

But maybe space for panels is an issue? I’d consider a ground mount for the new battery system

 

[JBertok]

Depending on where your main service panel is, it might be most practical to install a load center next to it, pull all your branch circuits out of the main panel, and move them all to the load center. Inverter documentation will refer to that second braker panel as a "critical loads" panel, but moving everything to it is what I am suggesting. In your main service panel you can install a huge circuit to the inverter and maybe a few auxiliary circuits in the garage you don't want on the inverter - always a good idea to have a few grid powered outlets when running a high-frequency inverter in case you have problem loads, like a circular saw, etc. I did a "critical loads" panel with my setup, moved all the branch circuits to it (worked out easy for me since everything runs through a raceway in the garage) and have a transfer switch that allows me to power the sub-panel with the grid if the inverters are down for any reason. It's ideal; I wouldn't change a thing with that. Moving all your loads over to the sub panel fed from your inverter also eliminates the need to monitor your mains coming in - no external load balancing is required at that point.

When the planning department wants a diagram for something existing it usually means an as-built. For the new configuration it would be a drawing from scratch appropriate to your exact configuration. I don't think the diagram for the manual would be adequate.

There have been changes since that system was built, so doing this yourself you can use this forum to get up to speed. The ones that come to mind immediately are the updated requirements for the PV that didn't used to exist. For example, all DC PV wiring has to be in metallic conduit before it enters a structure now. The PV has to have arc-fault protection and positive shutdown capability with an accessibly mounted and labeled switch. I don't think you can daisy chain panel grounds any more... and so on.

NEM grandfathering in California has a term limit, it's not going to be 1:1 for you forever, so looking into batteries is exactly the right path. Personally, I am holding out for domestically produced Sodium Ion; I just don't want chinesium anything, and Sodium Ion is shaping up to be the best value, even made here in the US. It's going to be a while before anything's available though. Best choice for you would be the compatible batteries made by the same manufacturer as your proposed inverter. They speak the same language by default.

Far as your roof mounts, you should be fine. The panels of today are larger than those of 15 years ago, so you'll probably be needing less hardware. Those old panels still have life in them, you could maybe mount them elsewhere with microinverters AC-coupled or something like that, or sell them.

Have you considered leaving the existing (and permitted) system completely intact? I didn't see mention of what it's using for an inverter currently but there's a possibility you could AC-couple if everything's compatible.

 

[Hedges]

Maybe you can install up to 4.3kW inverter while remaining under NEM 1.0.
A hybrid, able to handle much more PV and stuff the extra into battery. Supporting CT at grid connection, to shave import/export once you get pushed on to NEM 3.0

Here's the brand I use, and a model I haven't used yet. Other more popular brands will have more economical batteries and people on the forum have experience with them.

Discover the Sunny Boy Smart Energy | SMA America

The hybrid inverter at the heart of the SMA Energy System, with three backup options: Sunny Boy Smart Energy ► Discover now!

www.sma-america.com

Maybe 18kpv or SolArk could be configured to limit export to 4.3kW, satisfying utility so you remain under NEM 1.0 but supporting major house loads.

 

[bradley.r.zeller]

Thanks for the replies, all super helpful!

@Hedges - great idea to configure the inverter to only export a certain amount in order to remain in NEM 1.0. I'll look into that.

@JBertok - I love this idea about the critical loads panel but with all of my loads. Makes perfect sense. And it makes even more sense because I will be needing to relocate my service entrance for a future remodel and at that time, I can perhaps remove it all-together and add the additional equipment like diagram 4.4 shows. I've attached a wiring diagram of my understanding of what you said. Did I capture it correctly? Note, the diagram shows the new panel as a new 200A load center (even though I only have 100A service to my home); this is just a future proof thing for when/if I upgrade my service in the future.

Also, do you know why the diagram says I can only have a 70A breaker to feed the inverter? This would limit the grid passthrough which is not ideal. In my wiring diagram I propose having a 100A breaker feeding the inverter. Thoughts?

 

[12VoltInstalls]

diagram says I can only have a 70A breaker to feed the inverter

Maybe that’s the AIO specs?

LV6548 specifies 4awg and 50A breaker for example… 3ga will not even fit.

 

[Hedges]

Also, do you know why the diagram says I can only have a 70A breaker to feed the inverter? This would limit the grid passthrough which is not ideal. In my wiring diagram I propose having a 100A breaker feeding the inverter. Thoughts?

If inverter can backfeed grid through main load center, then "120% rule" limits breaker size, main breaker plus breaker backfed by inverter not allowed to exceed 120% of busbar rating. 200A main and 100A inverter breaker would be fine with 200A panel, but not with 100A panel.

There may be other ways to calculate that based on inverter capacity backfeeding it or programmed limit, but I'm not sure that's the case; don't think software settings are relied on. There are also other methods with different rules, but with 100A breaker feeding sub panel, don't think they apply.

 

[bradley.r.zeller]

If inverter can backfeed grid through main load center, then "120% rule" limits breaker size, main breaker plus breaker backfed by inverter not allowed to exceed 120% of busbar rating. 200A main and 100A inverter breaker would be fine with 200A panel, but not with 100A panel.

There may be other ways to calculate that based on inverter capacity backfeeding it or programmed limit, but I'm not sure that's the case; don't think software settings are relied on. There are also other methods with different rules, but with 100A breaker feeding sub panel, don't think they apply.

Thanks @Hedges! Still trying to understand this though...

In my head, replacing all loads on my existing panel with a 100A breaker feeding a sub panel (with all the same loads in it) is identical to what I have now, right? This shouldn't be breaking the 120% rule... if I am understanding things right.

My diagram also has a 100A breaker in my main panel which feeds the inverter. However, due to the interlock on the subpanel, the main existing 100A panel would never have two 100A loads simultaneously... which again, seems like it would be okay?

 

[bradley.r.zeller]

Oh - hmm. I guess the inverter is itself a load even if there are no downstream loads from the inverter (e.g. it can still charge batteries)... is that right? I think maybe that's what you were saying. I think I am understanding now.

So is this where the 70A breaker comes from: (1.2 x 225A bus rating) - 200A breaker?
The diagram includes this table (attached below) which I'm unsure if it is guaranteed to be true or just an example. In my case with a 100A breaker... it would be (1.2 x 150A bus rating) - 100A breaker = 80A.

Now, again back to the limitation of pass-through. I understand the 18k PV can pass through 200A from the grid through to loads. However, that would only be in the case where there is no solar and no batteries or your software configuration is such that you explicitly want grid pass-through. I don't imagine needing to pass through grid power unless if extra amps are required by my loads at a high-use time. In which case, it hopefully would not be any where close to the full 100A of my main panel... so maybe this is not an issue in practice?

That was a lot - hopefully I made some sense haha. Appreciate the help!

 

[finite]

5. Permitting - I’m a bit surprised I don’t see this topic talked about much on the community. I know it varies so much by location but I was wondering if a system like this typically requires permits or not. Again, I’m not exporting to the grid so maybe that plays a role in whether or not I need to get permits. I’d honestly prefer to get this system permitted for the sake of checking my work but it’s an intimidating path to go down because of the extra money and slowness of the whole process. Any guidance here?

While i would never try and shy anyone away from getting an inspection,as they tend to keep contractors honest, inspectors job is to make sure the work completed is up to local code, they typically do not and will not inspect to see if the equipment functions or is wired properly, in your situation one may overlap the other since you are dealing with a service

 

[Hedges]

In my head, replacing all loads on my existing panel with a 100A breaker feeding a sub panel (with all the same loads in it) is identical to what I have now, right? This shouldn't be breaking the 120% rule... if I am understanding things right.

The issue is, how much current can inverter backfeed into main panel? Plus how much current can come from grid (answer is 100A main breaker). The sum of those is what the busbar carries (a few other considerations go into that, but to keep it simple.)

Now if the ONLY load is a 100A breaker feeding sub panel, busbar will never exceed 100A anywhere. I'm not sure if the several rules applied by code use just that load.

My diagram also has a 100A breaker in my main panel which feeds the inverter. However, due to the interlock on the subpanel, the main existing 100A panel would never have two 100A loads simultaneously... which again, seems like it would be okay?

Sub panel with interlocks is fine.

Oh - hmm. I guess the inverter is itself a load even if there are no downstream loads from the inverter (e.g. it can still charge batteries)... is that right? I think maybe that's what you were saying. I think I am understanding now.

As a load, charging batteries, not a problem because 100A main breaker limits what can be drawn from grid. Although you have 100A breaker to sub panel and 100A breaker feeding inverter, total can't exceed 100A main.

The issue is only if inverter backfeeding main panel.

"Hmm, so then I'm not totally sure where that 70A breaker in the diagram comes from. If my main panel is 100A, then that would mean I would only have 20 free amps to not exceed the 120% rule... not 70." (snapshot of earlier post before edited)

Correct, with 100A busbar and 100A main breaker, 120% rule allows 20A PV breaker. 80% continuous loading means 16A allowed to avoid nuisance tripping, so 3.4kW inverter

So is this where the 70A breaker comes from: (1.2 x 225A bus rating) - 200A breaker?
The diagram includes this table (attached below) which I'm unsure if it is guaranteed to be true or just an example. In my case with a 100A breaker... it would be (1.2 x 150A bus rating) - 100A breaker = 80A.

Some inverters like mine spec 70A breaker maximum.

Correct that 225A busbar and 200A main breaker allow 70A PV breaker.

Yes, if you have 150A busbar and 100A main breaker, then 80A PV breaker.

Now, again back to the limitation of pass-through. I understand the 18k PV can pass through 200A from the grid through to loads. However, that would only be in the case where there is no solar and no batteries or your software configuration is such that you explicitly want grid pass-through. I don't imagine needing to pass through grid power unless if extra amps are required by my loads at a high-use time. In which case, it hopefully would not be any where close to the full 100A of my main panel... so maybe this is not an issue in practice?

If your pass-through loads were 80A then you'd want 100A breaker. If less you can use smaller.

What we would like is large pass-though breaker (no issue because protected by main breaker), but rely on limited backfeed from inverter. I'm not sure there are rules allowing that.

If the only other load on your main panel was 100A breaker feeding sub panel, I know nothing can get overloaded. But I don't think there is a rule for that. There is one where we ignore main breaker and just limit all branch circuit breakers (PV and loads) to 100% of busbar.

 

[bradley.r.zeller]

Ok, I think that is all making sense. Thanks for breaking that down for me.

Sounds like I’ll need to upgrade my service and panel. Bummer, this is turning into a bigger undertaking.

 

[bradley.r.zeller]

@Hedges - what if I swapped out my main breaker from 100A to 70A? Is that a terrible idea? haha.That would allow me to make the inverter breaker on my MSP 50A (see diagram below).

I understand that this would limit my grid draw down from 100A to 70A. However, in my head I think that could be okay since the whole point of this project and system is to self-generate all of the power my home needs anyways. The grid is solely a backup or supplement...

I'm trying to find ways to get started with this system w/o breaking the bank. But - it may just be that there's no way around it. Curious what folks think about this option. Thank you in advance!

 

[Hedges]

@Hedges - what if I swapped out my main breaker from 100A to 70A? Is that a terrible idea? haha.That would allow me to make the inverter breaker on my MSP 50A (see diagram below).

I understand that this would limit my grid draw down from 100A to 70A. However, in my head I think that could be okay since the whole point of this project and system is to self-generate all of the power my home needs anyways. The grid is solely a backup or supplement...

I'm trying to find ways to get started with this system w/o breaking the bank. But - it may just be that there's no way around it. Curious what folks think about this option. Thank you in advance!

Yes, smaller main breaker is a way to work within 120% rule. If 100A busbar, 100A x 120% = 120A, 120A - 70A = 50A max backfed PV breaker.

Check whether your main panel busbar is 100A, or 125A which gives more flexibility.

With 70A main breaker, limit max continuous current to 70A x 80% = 56A, to avoid nuisance trips.
Similarly, 50A breaker to inverter can handle 50A x 80% = 40A continuous.

Sure, could start this way to avoid breaking the bank.
And inverter with battery can provide "additional local consumption", limit draw from grid input to 40A while blending in more current from PV/battery. Inverter with CT at grid connection could also limit total draw to 56A, since you have other loads on main panel.
Find a way to shed bigger loads as needed.

A different rule besides "120%" is to ignore main breaker and limit all others to 100% of busbar.
With 100A busbar, keep 100A main breaker, install 100A backfed PV breaker, transfer all branch circuit breakers to a new panel.
That new panel could be backed up loads downstream of inverter.
Or, use Polaris connector to take multiple taps off output of 100A PV breaker. One tap goes to inverter, another to sub-panel for heavy loads you don't want to battery back up.

You can use interlocked breakers to manually select backfeed of that sub-panel from inverter. And you should use interlocked breakers in protected loads panel downstream of inverter to bypass inverter if failed, feed straight from grid.

The moment you add a battery, that will break the bank.


Consider a main breaker only panel for the service entrance, like I just did.
(It can be a meter + main breaker combo rather than two boxes like I put in. Siemens makes one.)
Be sure to use a model your utility approves of. I first put in "ringless", box cover goes over meter. Had to change to ring type, meter goes in from outside meter, and a wring wrapped around retains it.

Cost for utility transformer installation?

slightly OT. There was a review of the Emporia Energy Monitor on Amazon, which mentioned that the house meter records more kwh usage when the pull is unbalanced between L1/L2. Is this a possibility ?

diysolarforum.com

Then Polaris multi-tap connector fans out to multiple boxes.
Since your box has meter, probably replace it. If it has wires not busbars over to main breaker, might be able to just add main breaker box.
But if 100A only, good time to upgrade. And pick the series of breakers you want to use; I switched to QO.

I think most electricians would replace box in place, power out while doing it.
I mounted new box and had wires cut and swung over, power out only long enough to connect a backfeeding wire from new panel. After moving circuits I'll rip out and replace.

 

[bradley.r.zeller]

Oh! I see - I dig your idea to keep the 100A main breaker and then have only a single 100A breaker on that panel and tap it downstream to both the panel and the inverter. I think that's the best of both worlds! It would allow me to keep my 100A grid connection while also allowing my inverter to pass through the entire 100A if needed. And, the interlock would give me the flexibility to take the inverter offline for maintenance without losing power to my home.

I updated my diagram to confirm my understanding of your suggestion. Look right?

Thanks so much @Hedges !

 

[Hedges]

Yes, except I'd want 2 sub panels. One for heavy loads normally on grid, one for backed up loads normally on inverter.

Actually I like 3, so one critical loads (communications, and my AC coupled GT PV inverters) is always on, another for important backed up loads normally on but shed by relay for low battery SoC, one normally on grid.

Since you're going to replace main panel later, that could become the usually-grid panel.

But I like a main-breaker-only panel best, because even when feeding all three load panels from inverter, grid still feeds input of inverter. Before I did that had to switch back to grid feed manually, and no circuits existed that indicate whether grid was back up or still down.

 

[bradley.r.zeller]

Amazing, I like that configuration.

Circling back to the 100A main breaker and a single 100A breaker that is tapped to feed both inverter and panel… you said this:

A different rule besides "120%" is to ignore main breaker and limit all others to 100% of busbar.

Is there a name for this rule? And does that mean the 120% rule is not absolute… it’s just one of a few rules that must be adhered to. This configuration with a 100A main and a single tapped 100A breaker would not meet the 120% rule (that’d be 200A of “power sources” where only 120A is allowed (100 bus bar rating x 1.2). Did I get that right?

Another workaround I was reading about for workarounds to 120% rule are line side taps. The eg4 manual shows this configuration too. Does anyone know how utility companies typically feel about that configuration? Is the limitation in that scenario the gauge of the feeder conductors? Is this a safe configuration? I guess there’s still a breaker between the meter and inverter (grid breaker built into the inverter).

As always, thanks for the help!

 

[Hedges]

Not all rules to be adhered to, rather several rules to choose among. Multiple ways to avoid overloading the busbar. One is to limit current from all sources, another is limit current to all loads.

Only with great difficulty, knowing I saw this somewhere and searching repeatedly, was I able to locate it.

It is called the "sum" rule or "100%" rule, NEC 2017 - 705.12 (B)(2)(3)(C)

NEC 2017 - 705.12 (B)(2)(3)(C) says :
"The sum of the ampere ratings of all overcurrent devices on panelboards, both load and SUPPLY devices, excluding the rating of the overcurrent device protecting the busbar shall not exceed the ampacity of the busbar."

(In other words, sum of all breakers excluding main breaker.)

The Community Forum

Solar and energy storage Discussion forum, one of the most interactive and well organized forum.

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Solar PV Labeling (NEC 2017) - Ecuip Engineering

The NEC 2017 code simplified the labeling requirements for Solar PV. This article will show you what and where they are required.

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Solar Interconnection Methods 3: Backfeed breaker at any location on busbar (Sum rule)​

Governing Code(s): 705.12(B)(2)(3)(c)

For this method the sun of all breakers connected to the panel is less than the panel rating. The idea is that even if all breakers connected (both loads and sources) reach the maximum current there will not be potential for overload since the sum is less than or equal to the panel rating.

While this method is code compliant, it is not recommended as it assumes the sum of breakers will never exceed the panel rating. Even if the panel is not fully loaded at the time of install, it can be over loaded later if the homeowner adds more loads to the panel, at which point it has the potential to be overloaded and will no longer be code compliant.

Solar Interconnection Methods (Full Guide) - Ecuip Engineering

Navigating solar interconnection methods with diverse configurations and rules is complex. Connecting your PV system demands understanding this landscape.

ecuip.com

I think that last one should be fair game with 200A busbar, 200A main breaker, 200A backfed PV breaker, no other breakers. Or 100A, 100A, 100A.
Also called "Hawaiian Tie-In". Transfer all load breakers to some other panel downstream.

 

[bradley.r.zeller]

Ah I see, thanks for looking that up!

I had the utility spot my meter upgrade and they approved a max panel rating of 125A (up from my current 100a panel), based on the feeder conductors. Sadly, I’m underground fed so upgrading beyond 125 will be extremely expensive. This also means I can’t move the panel location like I had hoped without retrenching and laying new feeder conductors.

So, this has me rethinking things a bit.

Im thinking I’ll follow the manuals diagram 4.4 (attached below). Except I’ll be rating everything for 125, not 200. However, there are two components to this diagram that I don’t fully understand; and they are costly components so I’m trying to understand if I need them or not or can perhaps accomplish the same function but for cheaper.

1) the manual transfer switch - this switch is over $1000 at Lowes. Instead of a standalone transfer switch, could I not accomplish the same function (and remain code compliant) by connecting both grid and inverter output to the main panel directly (each on their own 125a breaker), and interlock them so only one can be on at a time? This seems much simpler and cost effective.

2) the pv interactive fused disconnect - what is the purpose of this? Is this a code requirement to disconnect the inverter from the grid in an emergency? Would an externally mounted RSD switch suffice? Also, why would it need to be fused? There is both a 200a grid breaker on the inverter and, in my case, a 125a main breaker immediately upstream. So the conductors between should be protected.

 

[Hedges]

I had the utility spot my meter upgrade and they approved a max panel rating of 125A (up from my current 100a panel), based on the feeder conductors. Sadly, I’m underground fed so upgrading beyond 125 will be extremely expensive. This also means I can’t move the panel location like I had hoped without retrenching and laying new feeder conductors.

After confirming I'm not actually adding any loads, PG&E approved my service upgrade with 200A main breaker without them doing any upgrades. I don't know what size their transformer is (might only be 25kVA?) and the wire drop is something like 2 awg aluminum. The worker who moved the wires over said that can handle up to about 150A.

My new equipment has 3/0 wires and the 200A main breaker. It would seem like I could overload the drop. For that matter, together with neighbors we could overload wires on pole and transformer. But maybe all that is protected by fuses at transformer. (Although with too much PV I think we could overload the neutral.)

200A panel and wires but 125A breaker might be the thing for you, can change later if utility feed ever upgraded.

Im thinking I’ll follow the manuals diagram 4.4 (attached below). Except I’ll be rating everything for 125, not 200. However, there are two components to this diagram that I don’t fully understand; and they are costly components so I’m trying to understand if I need them or not or can perhaps accomplish the same function but for cheaper.

1) the manual transfer switch - this switch is over $1000 at Lowes. Instead of a standalone transfer switch, could I not accomplish the same function (and remain code compliant) by connecting both grid and inverter output to the main panel directly (each on their own 125a breaker), and interlock them so only one can be on at a time? This seems much simpler and cost effective.

Yes, that works. Don't really need 200A feed-through inverter (yours limited to 125A anyway). If inverter supports 200A pass-through (or 125A), when grid drops inverter is overloaded and shuts down, unless automatic load-shed. Interlocked breakers lets you manually shed big loads.

Of course, it does defeat the "visible blade" feature of the disconnect before inverter, because invisible internal fault would go around and back to grid. But go for it, same as any generator interlock in a panel.

You probably want a critical loads panel normally on inverter, and an excessive loads panel normally on grid.

2) the pv interactive fused disconnect - what is the purpose of this? Is this a code requirement to disconnect the inverter from the grid in an emergency? Would an externally mounted RSD switch suffice? Also, why would it need to be fused? There is both a 200a grid breaker on the inverter and, in my case, a 125a main breaker immediately upstream. So the conductors between should be protected.

Visible blade safety switch, utility can isolate against backfeed from your inverter, without yanking your meter.

I think unfused is fine if equipment and wires are protected by upstream breaker, 200A in the case of the diagram you showed or 125A you have.