House Battery and Energy Management

The Misc. circuit has an interesting story. And by interesting, I mean long and boring. When we first moved in, the Misc. circuit was a collection of branches that seemed to feed about half the house. The whole upstairs minus the bathroom, but including a 120V Cadet heater. All the lighting on the main floor, the bathroom receptacle, and the two receptacles in the kitchen. Needless to say, it tripped a lot.

We had the refrigerator in the dining room, and pretty much couldn't use the kitchen or bathroom outlets for quite a while. I found that pretty much all the wiring was made of the old insulated knob and tube stuff. Some of which was in perfect condition, some of which was deteriorating from obvious overheating. When I remodeled the kitchen in 2016, I found hidden junctions in the wall without boxes, and mostly held together with wire tape. It all got upgraded, and the kitchen has 5 new circuits that are up to code. The range and the dishwasher already had their own circuits.

I've also been upgrading other parts of that Misc. circuit, to take more load off of it. I've since found more junctions in the attic with no boxes or wire nuts. Some wires are simply wrapped around exposed sections of other wires and covered with tape. The goal is to eventually make the whole circuit go away.

In other news, I decided to get myself an NEC 2020 code book. Now if only I had the decoder ring too... Well I may not be able to interpret it, but I'll at least be able to reference it when asking questions. Washington only adopts every other code update, so It should be good for another 3 years I think.

I've collected enough information now to know what circuits I want on the solar sub panel. Some of the circuits aren't finished yet, and some don't exist yet, so I've been planning things out a bit. I've been thinking about how circuits on sub panels are supposed to be "paired" so that the sub panel can be as balanced as possible. It's caused me to rethink the positions of all the circuits I have everywhere. I've color coded each circuit position on each panel so that I can easily see which positions would be paired so that one space is on bus A while the other space is on bus B. I hope that make sense.

2 Pole breakers are self balancing of course, but an example of a good pair would be the fridge and freezer. Both run often and take kind of vaguely the same amount of power. And with all these circuits on the sub panel, the main panel is freed up for future stuff.

I've also used colors to show which circuits need what. White are ones I'm still not sure about. Blue are ones I'm sure of, but haven't started yet. Yellow are in progress, and green are finished. I don't know when I'll be getting a heat pump or replacing the conventional water heater with a heat pump water heater. So for now, those are just sort of place holders.

Just for fun, here are the other two sub panels I'm working on:

The second floor sub panel is for all the wiring I'm replacing in the attic. When I moved in, the carport had an old Zinsco breaker panel feeding an outlet and a big ol' yard light. I'm sure that panel wasn't rated for outdoors, and it was pretty corroded. I took it out, but I need to replace it with a proper outdoor load center. I'd also like to expand the outdoor lighting and receptacles, so I'd like them to be on two separate circuits.

I'm down to choosing between a 16 space panel and a 20 space panel for the solar sub panel. 20 would give me spaces for future circuits, but I'm limited to 40A total, and I don't want to overload it. The main panel will have plenty of space for new circuits, just not powered by solar. The main and solar sub panels will be within inches of each other, so it physically wouldn't matter which panel I used for new circuits. 16 would save space, but then I'd be limited. The cost is about the same. I don't know.
  • Like
Reactions: cak
Continuing with the idea of balancing the two phases, I'm also thinking about the solar inverter and inverter generator, and how they have certain limitations because they'll be making split phase power too. So each phase of a 6kW inverter can do 3kW per phase. So you can't just have a limit of say, 4kW total on the inverter. It has to be split up. Also, the neutral wire has a 3kW limit too. As I learned recently, if the load is balanced, the neutral will see very little current.

I made a table based on my best guess for maximum current for the sub panel. Some were easy like the freezer or water heater. The lighting circuits I counted up how many Amps would be used if all the lights were on at the same time. The convenience outlet circuits were more difficult. I used data I've been getting from the Vue, and added in some specific devices like the air conditioners that haven't been running yet but will be at some point. Anyway, I came up with this:

These are not positions on the panel. Rather, these are circuits separated by which bus or phase they are using. Assuming all the circuits are running everything at the same time, I get some theoretical but very unlikely totals.

The inverter can actually invert a total of 25A per phase, but with load sharing, can send up to 40A per phase through to each bus. In the case of these maximums, that means around 10A would come from the grid to make up the difference that the inverter can't produce. But I'm well within the limit of how much the inverter could directly pass through from the grid to the panel.

Of course with a power outage, I wouldn't be able to use this much current. I'd have to do some budgeting. But that's easy. Looking at bus A, I'd never use the dishwasher and clothes washer at the same time. I already don't do that. Don't want to overwhelm my sewer connection. It also works out that each bus will have 2 window A/C units using about 4A each during the summer. Those could certainly be turned off for a bit to run other stuff. And the microwave only has a cumulative usage of maybe 5 minutes each day.

Something I didn't think about at the time I chose to have a split phase system, but I think is pretty cool, is that high peak loads will be separated between the phases. So having the freezer and refrigerator on separate phases will always keep their peak startup power separated, even if they were to activate simultaneously. I think it's extremely unlikely that that would happen, but still...

I counted the water heater twice, because it's a 2 pole circuit running on 240V. The heat pump on it uses about 400W, so each bus would see around 1.7A I don't know the peak current draw for it since I don't own one yet. It's 4,500-ish BTU, so I imagine about the same as a window A/C unit. Mine are 5,000 BTU.
I've been watching the circuits on my Vue, and I'm seeing something curious about my freezer. It uses 13-15W of power the whole time it's compressor isn't running.

Is that normal? My fridge uses nothing between cooling cycles except the light bulbs and the ice maker. The freezer has nothing extra in it. No defrost function; not even one light bulb. I verified with a multimeter, and made sure no other things were on that circuit. It was made in 1988, so after 35 years, maybe it's time to replace it. It sure keeps the food frozen after all these years.

At least part of it's life was pretty rough. My church owned it before me. It lived in a small room with no air circulation along with other freezers and fridges storing food for the food bank. Seems every year they had to replace one from burning out. No wonder. The room was like a furnace year round. Anyway, this freezer they couldn't get the door to shut anymore so they gave it to me for free. Turns out it just needed to be defrosted, and then the door shut fine.

In the last 24 days it's used 78.6kWh. I figure that's about 1,195kWh per year. Home Depot has some nice ones that only use 227kWh per year. Might safe me a few dollars. More importantly, it would free up some Amps on the solar sub panel for other circuits.
I've been watching the circuits on my Vue, and I'm seeing something curious about my freezer. It uses 13-15W of power the whole time it's compressor isn't running.
That'll probably be the heater elements (go figure, heaters in a fridge??!!!) they put around door edges to get the ice down...
Mine has these too. Can feel warm bits where they are. Got to be a better way!
I've been concerned lately that a 6kW inverter may not be enough for what I'm trying to do. The problem isn't Watts, but Amps. Using a split phase inverter, I'm limited to 3kW or about 25A per phase. That makes it difficult to add some of the more power hungry devices like the clothes washer and the microwave. I've started looking at inverters in the 8-12kW range, even though I don't plan to use that much power for the vast majority of time. The good news is that they're not much more expensive, and many have better features than what I was considering settling with.

One in particular that has caught my eye is the PowMr POW-SunSmart 10K. It's grid-tie, but I can still use it as an off grid inverter. It checks a lot of boxes for me, including being able to send over 40A to each phase continuously. 60A peak. So now I have two inverters on my short list.

In the meantime, I've been attempting to decipher the rapid shutdown requirements described by the 2020 NEC. Since my panels won't be on my roof, it makes things a bit complicated. Seems all solar arrays now need rapid shutdown capability, but only the roof mounted ones need remote shutdown capability. My plan at the moment is to install a lockout switch that shuts off both the positive and negative conductors. I haven't figured out yet whether to put it up in the array itself, or down by the rest of the electrical stuff as it enters the house. I think it just needs to shut off any conductors before they enter the house. But I'm not sure yet.

I've also been looking at how to ground the array. The aluminum frames I guess can have their own ground rod, though it still needs to be connected to the house ground rod. Seems the negative conductors of the whole DC system are also supposed to be grounded in one location. Assuming all the negative conductors have continuity. I'll have to be careful exactly how I do that.
Going larger is probably safer at the cost of more idle power consumption. But that is just what's baked into your calculation (just throw a couple more panels it's not really an issue once you go big ie. over 20kwh batt). If I was to start over, I would probably consider getting a Model 3 battery and hook it up to a HV inverter. 85kwh battery can be had for around $5-6k. That brings it down to around $60-70/kwh. BMS controlled from SimpBMS. Water cooled/heated. Dala here has shown hooking it up.

But as for the split phase thing, my Schneider does something neat when grid tied. If I try to pull 3kw from one leg, it only supplies 1.5kw from the inverter and uses 1.5kw from the grid. It then sends out 1.5kw through the other leg.

L1 = 1.5kw(inverter) + 1.5kw(grid)
L2 = 1.5kw(exported)

So technically the inverter is supplying a balanced load on both L1 and L2. It just sends one to load and the other leg to the grid. As far as the meter is concerned, no power is used since it was a net zero. This could be a Schneider thing, so I can't vouch for other inverters.

Another thing with inverters are how well it handles overloads. You can check out DavidPoz on youtube on his overload videos. He has done quite a few test on many inverters, such as starting miter saws where the surge kills most inverters. So my Schneider units can go 25% overload for 30 mins and 50% overload for 5 mins as long as the temp is within spec. That's common for most inverters that uses a toroidal transformer vs the other kind that's mosfets or whatever it's called, like my old mppsolar unit, which is light and cheaper to make, but god forbid if I had to go 25% over for more than a couple of seconds. So in that case, size appropriately.
I'm subscribed to David Poz and also Will Prowse. Trouble with them and many other reviewers is that they do their reviews off grid. So we rarely get to see how the inverters behave when connected and interacting. I know that Schneider and Victron use toroidal transformers. Many others use low frequency brick shaped ones. The high frequency ones use the tiny "electronic" transformers and don't have the overload capacity like you said.

That balancing feature on the Schneider is a neat trick. I don't think it's common. I've seen several videos of people "fixing" their Sol-Arc phase imbalance with auto transformers. Something interesting is that the PowMr actually uses less idle power than the EG4, even though its 4kW bigger. I'm still looking for reviews on it, and haven't seen any.

With 5kW to work with on each phase, I shouldn't have any overload situations. Even the peak startup current on my various loads will be less than the max continuous current. Here's a table of specs I put together comparing the two inverters that are pretty close to what I want:

One thing I'm curious about is that I don't know the PowMr's transformer type. They also don't say how long the inverter can hold the peak output. I'm assuming a fraction of a second. That's something I'll want to try to find out at some point.

Switching gears a bit, I've been attempting to understand rapid shutdown requirements. My situation is a bit different than normal, as I plan to have a pergola on my deck with the solar arrays as the roof. I'm not sure exactly how rapid shutdown should apply. I made a diagram (surprise!) to try to get my ideas across:

I've got three shutdown locations in mind. Lockout switch 1 would be located at the array and directly shut off the output there. The concern I have is that I think the shutdown is supposed to be grouped with the other shutdown locations. For me, that's utility, battery, and the generator inlet over by the house.

Lockout switch 2 would also directly disconnect the array before any conductors enter the house. And it could be located near the other shutoffs. But my concern there is that the conductors from the array to the house would still be live. Though they shouldn't be anywhere that a firefighter would ever need to take an axe to.

Lockout switch 3 would disconnect the solar array indirectly by controlling a set of relays. This allows the conductors to be shut of at the array and keeps the switch near the other shutoffs. This introduces extra parts and makes me feel like it would be more likely to malfunction. I know they make wireless devices that operate remotely. Those seem to be expensive and are even more complicated that using relays. They also require that I buy a control unit for each panel or every two panels. I'd like a single relay for the whole array. I think code allows that. There's also no reason for a firefighter to ever have to hack through an individual panel since they're not on my roof.

I wonder if I could find a 2-pole relay instead of having to use two normal ones. I also wonder if the rapid shutdown requires both conductors to be disconnected or if the positive one would be sufficient. Code just says to reduce the Voltage. Full isolation disconnect seems to be allowed separately. Like at the 2-pole breaker I plan to have inside the house. (That's the "B20A" box I have in the diagram.)

Speaking of codes and diagrams, I've been working on my whole system diagram. I decided to highlight each area as it pertains to specific articles in the NEC. I'm actually rather proud of this one:

I still need to read articles 702 and 710. Not that I understand it when I read it. The actual understanding comes from You Tube and websites, LOL.
One thing I'm curious about is that I don't know the PowMr's transformer type.
Screenshot 2023-04-24 at 12.50.14 AM.png

It is a high frequency inverter so it probably can't handle many more watts than it rated wattage. The max solar panel input voltage is more than most DIY solar systems. Not sure what Lithium battery activation means.
later floyd
Quick Disconnect - a key issue is what does you're local jurisdiction require?

In my case, for off-grid / traditional panels (non-micro-inverter) there must be 1) quick disconnect + 2) label with voltage/amps outdoors within 10ft of the array.

Roof array....

Yard array....

These quick disconnects block current from the array combiner box -> house. They also house the lightning arrestor connections (e.g. surge protection). They do NOT stop potential current within the panel wiring such as during a fire (wires melt together) or fireman using axes to break thru the roof etc.

As I understand it, some jurisdictions might require quick disconnect at each individual panel - e.g. one of the feature of panel based micro-inverters is they can offer this as an option - but my jurisdiction allows traditional arrays and this was not required at the time I did the permit.
Thanks Floyd! Where did you find that label?
I'd prefer to have a low frequency inverter, but as large (in Watts) as this one is, I think it would do fine. It has two MPPT inputs, but I'll only need one.

It looks like I'm going to have to contact L&I directly about a couple things. One being rapid shutdown requirements of a solar array that's neither on a roof, nor on the ground. The other is about batteries. I've read through article 480, and it looks like a DIY Lithium Iron Phosphate battery may not be an option:

480.3 Equipment

Storage batteries and battery management equipment shall be listed. This requirement shall not apply to lead-acid batteries.

From the NEC's list of definitions:
Listed. Equipment, materials, or services included in a list published by an organization that is acceptable to the authority having jurisdiction and concerned with evaluation of products or services, that maintains periodic inspection of production of listed equipment or materials or periodic evaluation of services, and whose listing states that either the equipment, material, or service meets appropriate designated standards or has been tested and found suitable for a specified purpose. (CMP-1)
Informational Note: The means for identifying listed equipment may vary for each organization concerned with product evaluation, some of which do not recognize equipment as listed unless it is also labeled. Use of the system employed by the listing organization allows the authority having jurisdiction to identify a listed product.

I guess I could look for individual cells and BMSs that are listed. L&I has a list of laboratories that they accept listings from. Nothing I want battery-wise is listed. Or I could just buy a listed pre-built set of batteries. Or I could go with lead-acid as those have no listing requirements.

Another possible issue. I went online to see about permits. They don't have any relating to solar. Closest I could find was generator transfer equipment. Another reason to go in and talk to them directly. I fear I may have to choose between doing this without permits/inspection or not doing it at all...
Thanks. As my grandpa Bob would have said, if it were a snake it would have bit me, LOL. Yep, it conforms to the UL1741 requirements. They list the 20kW max but don't mention how long it can do that. I bet it's for only a second or two. Plenty of time for the startup current from fridges and freezers.
I stopped by L&I today and asked about solar permits for homeowners. Turns out they have them under additional service installation. So I can definitely do my own work. I was so excited, I forgot to ask about rapid shutdown and ESS requirements as far as safety listing. I'll figure those out later I guess. Not like I'm in a hurry. For now, I can go back to learning stuff and making plans.
I really wanted to build my own battery for this. It took a while, but I've come to terms with needing to buy a UL listed battery. My DIY battery would have been 14kWh, and cost the same as a store bought 5kWh battery.

The battery I'm looking at by the way, is the EG4 LL 48V V2. This seems to be the most popular brand folks out there are using, and I have no particular preference as long as it works. The specs are all good, and it's loaded with a few features my DIY battery wouldn't have. The battery has a projected useful lifespan of 15-20 years of daily charge cycles at 80%. Who knows what kind of technology will be around to replace it by then?

I also did a lot of figuring to see how much gasoline or propane I'd need to keep the battery charged for a month. In case of a long term power outage. Worst case being December/January, (least solar energy available) it would take about $40 in gasoline or about $145 in propane (priced at the moment) to keep the battery going, with little solar to supplement. I'd need to keep about 10 gallons of gas on hand or about 50 Lbs of propane to avoid having to go to the gas station. Which could be difficult if the roads were really bad. That's totally doable. I keep ethanol free gasoline on hand for all my carbureted engines anyway.

Of course, a short term power outage would probably not need the generator at all. Especially if I got a second battery at some point. But even 4kWh of useful energy from the battery is enough to last a little over 2 days. So I don't have to worry about it getting too discharged at night between solar availability. I've also got my eye on a chest freezer that should be more energy efficient than the antient unit I'm using now. The fridge and freezer are about 90% of the energy I'd need in the event of a long term power outage.

Anyway, things seem to still be on track. I just got an estimate on getting a heat pump installed. Pricy, but it seems reasonable. Looks like they can add the heat pump to my existing air blower and furnace. That reduces the cost quite a bit.
Back in post number 69 I realized that I had a multibranch circuit (two 120V circuits sharing a common neutral) that were done totally wrong. A couple weeks ago, my dishwasher GFCI receptacle went bust. How are these two things related? Well, one of the multibranch circuits was on a tandem breaker, and the other circuit on that tandem breaker was the dishwasher.

Since my dishwasher was out of commission anyway, I pulled the wires for it and the multibranch circuits and replaced all the breakers. The dishwasher now has its own full sized breaker, and the multibranch circuits are on a 2-pole breaker, as code requires. I've also bought an outdoor load center that I intend to feed with the multibranch cable. Then the two circuits can be separated out and put on their own GFCI breakers. And that will be the end of the multibranch circuit woes I hope.

One bit of fun I had changing out the GFCI receptacle for the dishwasher was that the box it was in was really too small to fit the chunky receptacle, and the hot wire got squashed in the back and the insulation was damaged. Being a properly grounded metal box, the breaker immediately tripped as soon as I tried to turn the breaker on. So in addition to having to repair the cable, I also decided to get a bigger receptacle box. I got the extra deep Legrand Wiremold box to replace this guy:


In other news, I took a lot of measurements in the basement where my power-wall will be set up. I was then able to make a scale drawing to help me figure out where and if all the components will fit:

Even the cinder blocks are drawn to scale. Anyway, the main panel location is fixed, since it's already there. The sub panel really needs to go right next to the main panel so I don't end up having to extend all the wires for the circuits that will be moving from the main panel to the sub pane.

The inverter location is weird, but the one I'm looking at (at the moment) requires 200mm on each side and 500mm above to be clear for ventilation. It just barely fits. To the right of the drawing is a window and washing machine. So nothing can happen any further that direction.

The battery will most likely be in one of those server racks that seem really popular right now. I'm not sure exactly where that will go, or the transfer switches, or the DC breaker panel. The generator inlet/breaker box will be outside, along with shut-offs for the battery and solar panels. I'm not sure where they will go either, but outside there's a lot more room.

I've got the new sub panel unboxed on my table. I hope to at least get it mounted on the wall this weekend.
Turns out there's still a lot of work to be done before I can mount the sub panel. I had to do a lot of rearranging to get a proper space to work in.

I also realized that I need to insulate between the floor joists before the sub panel and wires are in the way. And I've got to move the washer and dryer to the right a couple feet to make way for the inverter. As long as that's all being moved around, I cleaned up and expansion-foamed the spaces behind the appliances too. Six in total.

Once the foam has cured, I'll add some ridged foam insulation up there too. We lose a lot of heat in the winter out of these spaces. So sealing them up and adding insulation should really help.

A while back, I bought this expansion foam gun:

I gotta say, this is one of my favorite tools. Those cans with the straws always made my hands cramp within minutes, and they make a huge mess. Also, the stuff solidifies in the straw, or even the valve, so if you don't use it within a day or two, the can is ruined. This gun has had the same can on it for months at a time, with no such issues. and using it is so much cleaner and easier. It looks like a bit of a mess in the picture, but I've had it for many years. Anyway, just had to give whoever makes it some free advertising, LOL. Pretty sure I got it from Amazon.

It's also a good time to clean behind the appliances since they're out of the way. As well as digging out all the stuff that has fallen behind them over the years. I'm also going to have to remove the washing machine receptacle. The conduit is right in the way. Projects always have way more steps than you think.
Sub panel is up! That was a job and a half. But it's good and stuck now.

I'm thinking of relocating the drain pipe next to it. Not sure yet. But the gaps between the joists all have ridged foam now in addition to the expansion foam I used earlier.

I've been working on the design for this area. The real thing is starting to look like what I imagine:

The DC side is turning out to be more complicated than I thought. I don't think I'll be able to put all the breakers in a single box. Also, I'm looking at getting a shunt trip breaker for the battery, so it can be remotely shut off from outside. That's a code requirement where I live. Either a direct shut off or remote shut off outside. I've seen people using these huge 3-pole brakers for their batteries. Seems like overkill, but then I haven't found any yet that are specifically made for batteries. I don't know yet what would be easier/cheaper: running the big battery cables outside to a switch and back in, or getting one of these shunt trip breakers.

Another code requirement that I may have to follow is rapid shutdown for the solar array. Not sure since my array won't be on the roof, but if I need it, the Tigo RSS products look promising.

I'm drafting a list of questions to bring to L&I since they're the ones who will be doing the inspections. Hopefully there will be someone there willing to answer them.
Last edited:
I've spent many more hours trying to decode the code. I've had some limited success. I learned that in order to have a grid-tied inverter, even if I don't sell power back to the utility, my 200A main panel must be rated for 225A, or the main breaker must be downgraded to 175A, or I need a new service panel. Fortunately, I found some fine print on my panel that says it is rated for 225A, so I'm good.

Next I found out that the solar array circuits must have ground fault detection and arc fault interrupt capabilities built-in somewhere. Typically this is done inside the inverter, but the PowMr inverter I thought I was going to buy doesn't have these things. Nor was I able to find them as separate devices. So I went back to the beginning (again) and started researching inverters. There are none in my price range that do what I need, but the EG4 18k is the cheapest that checks all the boxes. It brings its own issues, like its too big to fit in the house, but I think I can solve all of them. It also solves a number of issues.

I learned, for example, that temperature coefficient of solar panels can be an issue if your array is right at the edge of what the inverter can do. The PowMr could only handle 500V of solar, and my array was going to be rather close to that. With the temperature coefficient, I was going to go past the 500V limit in cool weather. So I was going to have to do without a panel to get the Voltage down. The EG4 on the other hand can do 600V. With all 12 panels I want, it would have to be -61F before I have to worry. The coefficients of current and power calculations gave even more ridiculous numbers.

Reading about grounding requirements almost melted my brain. Lots more questions to take to L&I. But I think that my water pipes are grounded wrong-ish. If I understand right, grounding water pipes serves two functions: 10ft+ metal pipes buried in earth can serve as a supplemental grounding electrode, but its not required. Also, grounding metal water pipes makes the water pipes "safer". That one is required.

I made a diagram of what my grounding system looks like now:

I don't know if my metal drain pipes need to be grounded. But they are. The cast Iron and steel drain pipes meet up just under the concrete basement floor, and then immediately convert to concrete pipe. The fresh water from the city is galvanized steel and extends at least 20ft across the yard to the meter, and is about 2ft underground. So that definitely would qualify as a grounding electrode.

The cold water distributed to the house is directly connected to the fresh water pipe, but the hot water pipe is not. My house was built in 1941, and over time, parts of the plumbing have been replaced with ABS and CPVC. There's no continuity between the hot and cold, nor is there one to the water heater. It's all hooked up to plastic pipe. So I'm thinking the steel hot water pipe needs to be grounded too.

Also, I think (but I'm not sure) that the two proper grounding electrodes are supposed to be bonded directly together. Or they should at least connect on the same bus bar rather than on opposite sides of the breaker panel. So here is my plan to improve things, at least for the moment:

As for wire sizes, I don't know if these sizes are correct or not. They're at least in the ballpark. I think it depends on my service conductor sizes. They're not labeled, and I'm hesitant to stick my metal caliper inside the breaker panel for some reason...

In other news, payday is coming, and I'll be getting the ATS and hopefully some THHN wire so I can actually energize the sub panel. The "server" battery rack I wanted seems to have been discontinued. I haven't found a replacement yet that is short enough to fit how I want. I'm considering building my own. With the inverter being outside, I do get some inside real estate back.

I've also been calculating wire sizes and conduit sizes. Those are now added into my scaled drawings:

I'm using to make sure I use conduits big enough that I don't go over 40% fillage. Also, doing a mirror-image of this diagram helps me to locate where the conduits will go outside. Looks like I need to drill 2 holes in the wall. One for AC and one for DC:

My grounding electrode really does stick up that far. While reading about grounding, I realized that my power meter and mast are not grounded. I did some research, and it turns out that's a whole can of worms I don't need to open. So I'll leave it be. I'm a bit concerned about the water spigot being so close to the inverter. But the inverter needs side clearances, and can't be moved up much higher, or I won't be able to use the touch screen interface. It's ground fault protected though, so I suppose it will be ok.

I think I need to build an awning of some sort to protect the inverter from direct sunlight and rain. I wanted to do that over the doorway anyway, so I'll just extend that project a few feet to the left.
I realized that my power meter and mast are not grounded
They probably are grounded, just not at the house. If you look closely at the wires, there's one of them connected to the mast, this is the ground wire. This wire goes back to your power pole. At the pole there's a wire that runs from the ground lead down the pole to a coil of copper at the bottom of the pole.
A lot of ppl mistake the 3 wires coming from the pole as Hot, Neutral, Hot. But the Neutral is already grounded prior to the main breaker


Also remember that at your main panel, Ground and Neutral are bonded as well. So this finishes the grounding of the mast on your house side.
I don't know if my metal drain pipes need to be grounded
It's not that these "are grounded", the installation was using these "as the ground" because they make direct connection to the damper soil, making better electrical conductivity. This was a general practice in the past. When it comes to gas pipe lines, those are also grounded, usually in multiple places, to keep static and voltage differences at a minimal.
So I'm thinking the steel hot water pipe needs to be grounded too
The pipes "inside" the house were probably originally used "as the grounding" to most everything else, especially the water heater. If the grounding has been severed, because of metal being replaced with pvc, then yeah, you need to add extra grounding to the water heater. If the wiring to the heater already has a ground wiring running with it, then there's no need to do extra grounding, unless you plan on using the metal pipe as a grounding source.

In your diagrams you took the two groundings in your mains panel and combined them. I would leave them split on the connectors as they are bonded anyways. Unless you are doing this to tidy up the box and make it more manageable, there isn't really a need to put them all on the same lug strip. The panel box housing bonds the Ground and Neutrals in the main box. Unless what you have labeled is actually a sub-panel, there's no reason to separate the Ground/Neutral connections.

More grounding paths/routes are generally a good thing. One of those things too much is not a bad thing.
Well, the power mast and meter box are between L&I and PUD3 (The AHJ and utility) so it's not something I'm responsible for. But it is interesting anyway. I'll take a look in more detail sometime and see how it's done exactly if I can.

My water heater is grounded through the circuit cable. But it's isolated from all the metal pipes by sections of plastic pipe. And my water supply pipe is considered a third optional grounding electrode. If you remember the picture from post 117, you'll know that my main panel could really use some tidying up, LOL.

Also while poking around, I discovered that my second ground wire has a junction in it:

This dates back to when I bought the house in 2011. After the inspection, but before we took ownership, someone came and relieved us of all our basement wiring and copper plumbing. The bank, who sold us the house, sent out a fake electrician to "fix" it. No permit, no inspections, the guy didn't even bring any 12AWG wire. It wasn't until after he left that I saw the ground wire missing. So I bought some and spliced it back in. Never occurred to me that junctions on that wire are prohibited. I haven't thought of it since until now. Well, that will get fixed soon too.

All this grounding stuff came about because I'm looking deeper into solar panels lately, and I've seen a lot of debate and disagreement on how they should be grounded.

Well first, here is my plan so far:

I measured out the deck area I'd like to cover (dotted square). Since the top will be at an angle, I did some clever math to determine the slope and extra length. Ok, I cheated and used this website: My optimal solar angle would be 34.5 degrees, but I won't get anywhere near that. I'm thinking about 22 degrees. Any more than that and I'll have height issues.

I don't know if the Sungold Power modules are what I'll actually use, but I'm using them for now as an example. I'll have a little overhang on the left, but as far as I know, that's ok. On the right, I want a space between the array and my house so I can get up there to clean off the panels periodically. Every spring we get pollinated by the local trees. It leaves a sticky yellow film on everything, and rain does not wash it away. Also, the last couple summers, the air quality has been terrible. And that leaves a sticky brown grime on everything. Maybe I'll put a soaker hose along the top so I don't have to hold both a hose and a squeegee on a long stick at the same time as balancing on the ladder.

I fretted for quite a while about the extra cost of a rapid shutdown system. Since the array is on a pergola, on a deck, and only the deck is attached to the house, and neither are considered livable spaces... It's really up to the AHJ to decide. But that's moot now, because I decided to put Tigo TS4-A-O modules on each panel for optimization. Just so happens they also do monitoring of individual panels, and have rapid shutdown functionality. My return on investment is shot anyway because of the need for NEC compliant batteries and inverters, so WTH.

Another thing up to the AHJ will be how the array is grounded. Like, will they allow/prohibit/require a separate ground rod? Do they consider the ground wire bonding all the panels together a Grounding Electrode Conductor, or Equipment Grounding Conductor? I have my opinion as to what the code actually means, but only their opinion matters.

By the way, I found this website:; anyone else know of it? Among other things, it has the NEC2020 as modified by Washington State. I'm finding it easier to reference at the computer than the paper code book I bought.