New solar install 14.6kw/Eg4 18kPV

[PhilIA]

I am planning a 14.6kw install using 36 SEG Solar 405w bifacial panels with an EG4 18kPV and a single PowerPro battery. The battery is mostly a nicety, we would be on inflow/outflow metering, don't lose power often and have a generator for longer power outages. I have started the 1-line diagram, attached below, looking for feedback and also have a few questions.

I will be doing whole home backup, and have been following the whole home backup using feeder tap in the manual. It states the main service breaker must be stand-alone, not a load-center, why? My outdoor load center has a 200a main breaker feeding a 225a busbar with feed through taps on the bottom feeding the MCP. It seems the 120% rule should apply, allowing 56 amps from the inverter.

12 panels will be on the garage roof, 24 will be ground mounted about 125 feet south of the garage, 50 feet south of the power panel. Where am I required to have DC isolators, can they be inside the garage near the inverter/MCP on the south wall?

Does the exterior RSD switch need to be located near the 200 amp main service disconnect in the outdoor load center, or can it be placed on the exterior wall where I plan to have the feeder tap, feeder tap breaker and inverter disconnect? Can I use 2 breakers, 1 of which is the feeder tap breaker, in place of the manual transfer switch?

I plan on APSmart RSD-Ds as it appears Tigo are not SunSpec and would require extra parts.

I appreciate all the help.

 

[glandpuck]

I think the code requires that the meter and main breakers are separated from the main load panel if you are going to use the main panel as a whole home backup (now really a critical loads subpanel) and the inverter in pass through mode. The inverter or system should have a built in ATS to switch current from grid to battery in the event of grid outage. The output from the inverter into the reconfigured main panel would have the 200 amp capacity and go into the center taps of the panel. The 120% rule I believe only applies if you are feeding power from a grid tied inverter onto the buss bar and breaker and then to loads and back into grid through main panel with meter. In your case, if setting up whole home backup and selling to grid, your output would go back to grid via the mains and meter and not to the load panel. Make certain your utility provider okays converting main panel into a whole home load panel and removing meter mains and breaker. Note, your 14.4 single battery, at 240 volts has 60 amps capacity. If your load is say 2 kW/h you get 7 hours. Point is, you wlll not have enough power for an overnight outage.

Note, the comments hare are to be verified by a licensed electrical professional if implemented.

 

[zanydroid]

I plan on APSmart RSD-Ds as it appears Tigo are not SunSpec and would require extra parts.

I thought shutdown only was sunspec.

Shutdown plus optimizer is not sunspec

IIRC APsmart dual shutdown only was cheaper than TIGO

 

[zanydroid]

Regarding the 120% rule, any panel with primary and non primary power source coming into it from two different places needs to comply with either that, or 100%, or other rule from that section.

If the power only comes from one side, which is the case if downstream panel from the output of the inverter, then no special provisions needed.

Now the electrical bus from inverter to grid needs to comply with those rules. Presumably if you parrot the SLD in the manual you are fine but you should still show the SLD of your specific system in a manner that makes it easy for someone to check for you. It will also be checked by your AHJ

 

[zanydroid]

Looks like you translated the 18kpv SLD.

If you have zero load breakers on that left hand side 200A / 225A bus you can stack a total of 80%*200A worth of inverter output. If you add load breakers then you need to comply with 120% rule on that panel, which probably nets out to the 56A you said.

I assume EG4 did the calculations for the breaker and backfeed size on the feeder tap that they have in the manual, I didn’t verify it.

 

[PhilIA]

I thought shutdown only was sunspec.

Shutdown plus optimizer is not sunspec

IIRC APsmart dual shutdown only was cheaper than TIGO

I only need shutdown, the garage roof should have no shading issues. I can't find anything confirming TIGO is SunSpec. Prices are similar if the TIGO CCA is not needed.

Looks like you translated the 18kpv SLD.

If you have zero load breakers on that left hand side 200A / 225A bus you can stack a total of 80%*200A worth of inverter output. If you add load breakers then you need to comply with 120% rule on that panel, which probably nets out to the 56A you said.

I assume EG4 did the calculations for the breaker and backfeed size on the feeder tap that they have in the manual, I didn’t verify it.

No load breakers on the left load center, and no need because I can install them on the right side load center(currently has a couple outdoor outlets). Could I legally do this, or would I need to lock out the ability to install breakers or apply warning stickers? I'd prefer not to swap out the load center.

I would need to confirm the wiring size. 4/0AL is what is currently installed from load center to MCP. This line shouldn't ever see more than 200 amps from what I see.

What device would I use for the feeder tap? Polaris connectors? Could they go in box for the feeder tap breaker?

 

[zanydroid]

(Not an electrician and I don't own the 18kpv, I just keep tabs on it)

Hmm, I thought the TS-F was SunSpec compliant based on the cost/complexity of it, and it has the same cost if you have to buy a transmitter anyway. But if you have transmitter in the inverter you should use it, save some money, neater install, and fewer ways to mess it up.

No load breakers on the left load center, and no need because I can install them on the right side load center(currently has a couple outdoor outlets). Could I legally do this, or would I need to lock out the ability to install breakers or apply warning stickers? I'd prefer not to swap out the load center.

Stickers are fine in the AHJ that I've seen solar setups for (2 or 3 of them, randomly, at my own house and friend/family's house).

What device would I use for the feeder tap? Polaris connectors? Could they go in box for the feeder tap breaker?

I think the manual lists two or three options. I would say polaris style is one way, insulating displacement is another.

Not sure if they can go in the box, it depends on what kind of box it classifies as. I would say yes. For boxes subject to the 40% cross-sectional area rule you have to make sure you don't plug it up. It's probably not worth worrying about, there's not that much wire in there

 

[zanydroid]

I would need to confirm the wiring size. 4/0AL is what is currently installed from load center to MCP. This line shouldn't ever see more than 200 amps from what I see.

Check 705.12A

Load-Side Source Connections | UpCodes

Explore a searchable database of US construction and building code. Code regulations are consolidated by state and city for easier navigation.

up.codes

Technically speaking I don't think this is a feeder tap, it's a feeder. Tap implies conductor ampacity varies, etc. But whatever.

 

[PhilIA]

I think the code requires that the meter and main breakers are separated from the main load panel if you are going to use the main panel as a whole home backup (now really a critical loads subpanel) and the inverter in pass through mode. The inverter or system should have a built in ATS to switch current from grid to battery in the event of grid outage. The output from the inverter into the reconfigured main panel would have the 200 amp capacity and go into the center taps of the panel. The 120% rule I believe only applies if you are feeding power from a grid tied inverter onto the buss bar and breaker and then to loads and back into grid through main panel with meter. In your case, if setting up whole home backup and selling to grid, your output would go back to grid via the mains and meter and not to the load panel. Make certain your utility provider okays converting main panel into a whole home load panel and removing meter mains and breaker. Note, your 14.4 single battery, at 240 volts has 60 amps capacity. If your load is say 2 kW/h you get 7 hours. Point is, you wlll not have enough power for an overnight outage.

Note, the comments hare are to be verified by a licensed electrical professional if implemented.

The EG418kPV would handle the transfer.

Would only expect to use the battery for 2 hours during an outage, after that we would be setting up the generator. Would be required to run a well pump and the furnace during the winter.

 

[zanydroid]

Frankly if AHJ does not accept warning stickers as enough and requires shit to be ripped out I would ask to see the manager. That is unreasonable.

 

[zanydroid]

LOL this might explain the SunSpec issue:

Tigo Energy Files Patent Infringement Suit Against SunSpec

www.tigoenergy.com