Automatic transfer switches!!! How come there is such vague info about this?

[Restlesseye]

I have a Sol-Ark 12k in a grid tied system and batteries are used as a UPS. Essentially my batteries are doing nothing. Grid goes down, because of the safety of anti-islanding, I can not use the power from my batteries or my PV should the grid go down. I should have made a panel for my critical loads and run my AC and fridges etc.. through there but don’t want to go through the hassle of inspection and getting the utility company involved again. I have net metering in WA and the system works just fine, but am disappointed during a power outage.

I am setting up a new system in a different house now. It is on-grid but I want to run it off-grid with PV and battery while having the grid for backup. Probably get a Sol-Ark 15K or an EG4 18KPV and then move my two fortress 5.4kw batteries to the new system.

My service to the home is 200AMP. Can I switch between shore or solar through an automatic transfer switch? How about a manual switch? the Sol-Ark 15K and EG4 18K can both handle 200AMP. I don’t want to set up a critical load panel and no plans to sell back to the grid.

Thoughts, discussions, prayers?

 

[zanydroid]

Why did you create a second thread instead of replying to your first one?

Post a SLD for more specific help.

I wouldn't call the ATS situation vague, it's understood pretty crisply in the zeitgeist (AHJ, this forum, regulations)... There is something kind of weird with your design process and prioritization though. You are buying top tier equipment (from the purposes of this forum) but not getting the performance you want. I call out examples of this in (A), (B) below.

The type of transfer switch you want is probably closest to what code calls a Microgrid Interconnection Device. However, these are currently custom designed for each line of inverters OR built into the inverter itself. The SolArk 12K, SolArk 15K, and 18kpv have MIDs built into them.

(A) You don't need the utility company involved for a critical loads panel, you just need AHJ. Setting up a subpanel next to main panel / inverter is not a big deal if you plan ahead and position the inverter and main panel next to each other. You can add a subpanel in < 1 day, and then individually move/extend circuits from main to subpanel. Some people don't even get this work inspected.

(B) Since the 18kpv and SolArk 15K have 200A transfer switches internally, the "canonical", elegant way to do this is to move all your branch circuits to a new subpanel below the 18kpv and SolArk 15K.

I don't think you can achieve what you want with an ATS, since you are trying to split your main panel between grid power and off-grid power, and ATSes generally operate on a subpanel. At that point, you might as well save your money and use the 200A transfer switch inside the inverter. You are probably paying a $1000 premium on the inverter for this capability anyway, silly not to take it.

You can add a manual interlock to your main though, and interlock the main breaker with a backfeed breaker. The backfeed breaker would be fed from the output of the 15K or 18kpv. The tricky part here is that you actually want a 3-way interlock to prevent the output from the inverter from feeding into the input of the inverter.

IE, the main panel has two states:
- Mode 1: Main breaker on, breaker TO inverter on. Breaker FROM inverter off
- Mode 2: Main breaker off, breaker TO inverter off. Breaker FROM inverter on.

There was a post a few months ago showing a cool way to do this with TWO interlock plates strategically placed on the same main panel. It is not that standard but it is safe.

 

[ksmithaz1]

Amazon.com

Move the grid mains from your panel to 'II'(2, secondary) put the SolArk "Load" ouput on 'I'(1, Primary) and feed the panel from common. You will need to de-energize the mains to the panel first.. Run SolArk in off-grid mode.

 

[Restlesseye]

Why did you create a second thread instead of replying to your first one?

Post a SLD for more specific help.

I wouldn't call the ATS situation vague, it's understood pretty crisply in the zeitgeist (AHJ, this forum, regulations)... There is something kind of weird with your design process and prioritization though. You are buying top tier equipment (from the purposes of this forum) but not getting the performance you want. I call out examples of this in (A), (B) below.

The type of transfer switch you want is probably closest to what code calls a Microgrid Interconnection Device. However, these are currently custom designed for each line of inverters OR built into the inverter itself. The SolArk 12K, SolArk 15K, and 18kpv have MIDs built into them.

(A) You don't need the utility company involved for a critical loads panel, you just need AHJ. Setting up a subpanel next to main panel / inverter is not a big deal if you plan ahead and position the inverter and main panel next to each other. You can add a subpanel in < 1 day, and then individually move/extend circuits from main to subpanel. Some people don't even get this work inspected.

(B) Since the 18kpv and SolArk 15K have 200A transfer switches internally, the "canonical", elegant way to do this is to move all your branch circuits to a new subpanel below the 18kpv and SolArk 15K.

I don't think you can achieve what you want with an ATS, since you are trying to split your main panel between grid power and off-grid power, and ATSes generally operate on a subpanel. At that point, you might as well save your money and use the 200A transfer switch inside the inverter. You are probably paying a $1000 premium on the inverter for this capability anyway, silly not to take it.

You can add a manual interlock to your main though, and interlock the main breaker with a backfeed breaker. The backfeed breaker would be fed from the output of the 15K or 18kpv. The tricky part here is that you actually want a 3-way interlock to prevent the output from the inverter from feeding into the input of the inverter.

IE, the main panel has two states:
- Mode 1: Main breaker on, breaker TO inverter on. Breaker FROM inverter off
- Mode 2: Main breaker off, breaker TO inverter off. Breaker FROM inverter on.

There was a post a few months ago showing a cool way to do this with TWO interlock plates strategically placed on the same main panel. It is not that standard but it is safe.

Thank you for your prompt reply regarding my idiopathic conundrum. In hindsight, you were right—I’ve been approaching this matter incorrectly. The state of Washington, the utility department, and the county have specific rules regarding inspections, which also impact home insurance policies. Without proper inspections, if my house were to catch fire, I would be in serious trouble. Fortunately, my first installation passed all inspections, including the roof mounting. For my second installation, I’m dealing with an older house and plan to move forward by transferring all my loads to the critical load sub-panel. The biggest nuisance is going to be extending the AC, refrigeration, well pump, and computer servers to the new critical load panel. I hate making connections and extending. Luckily, this second location only has one AC unit, but it does have a well pump that I cannot afford to lose power to.

Oddly enough, I do have one critical load (Starlink internet/routers/servers) attached to my current Sol-Ark 12K that lost power when the grid power went out. I’m calling Sol-Ark tomorrow to trouble shoot my configuration.