100 amp solar/ battery output into 200 amp panel

S

Shireelec

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Location
Massachusetts
Occupation
Electrician
Hey we got this design where the customer has an Enphase battery system with solar. The Enphase IQ combiner 6C controller has an output of 100 amps being fed back into the main panel. The house has a 200 amp service with service disconnect outside and a 200 amp panel in the basement. The drawing shows #1 AWG going from the enphase controller to a "line side tap" in the main panel. However this would mean it's after the main breaker and technically on a feeder. I'm trying to figure out the proper way to connect this system. We are on 2023 NEC. Thanks
 
You are going to need to connect the 6C Combiner output on the line side of the outside 200A service disconnect if the intent is to utilized NEC 705.11 supply side connection (your "line side tap" reference). If the intent is to connect to the feeder between the service disconnect and the main load center, then you are making a load-side connection per 705.12(A), and as long as the service disconnect has a 200A OCPD, and the main load center has a 200A OCPD, and the Feeder conductors are rated for not less than 200A, then you can tap the feeder and connect the 6C Combiner via the 1AWG AL conductors. Is there PV only at this site or also battery storage?
 
solarken said:
You are going to need to connect the 6C Combiner output on the line side of the outside 200A service disconnect if the intent is to utilized NEC 705.11 supply side connection (your "line side tap" reference). If the intent is to connect to the feeder between the service disconnect and the main load center, then you are making a load-side connection per 705.12(A), and as long as the service disconnect has a 200A OCPD, and the main load center has a 200A OCPD, and the Feeder conductors are rated for not less than 200A, then you can tap the feeder and connect the 6C Combiner via the 1AWG AL conductors. Is there PV only at this site or also battery storage?
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There is 9kW of solar and 40kWh of batteries (four Enphase 10C batteries.) I would like to connect it if possible to the feeder between the service disconnect and the main panel as that's how it shows it on the drawings however they do call it a line side tap when that's not the case. The service and feeder is all 4/0 Aluminum. I'm trying to make sense of 705.12(A)
 
Shireelec said:
There is 9kW of solar and 40kWh of batteries (four Enphase 10C batteries.) I would like to connect it if possible to the feeder between the service disconnect and the main panel as that's how it shows it on the drawings however they do call it a line side tap when that's not the case. The service and feeder is all 4/0 Aluminum. I'm trying to make sense of 705.12(A)
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It looks like the feeder conductors would need to be rated for 325a (sum of the rating of the main OCPD and 125% of the output circuit current). but if the combiner 6C is a listed PCS then it would be compliant?
 
Shireelec said:
It looks like the feeder conductors would need to be rated for 325a (sum of the rating of the main OCPD and 125% of the output circuit current). but if the combiner 6C is a listed PCS then it would be compliant?
Click to expand...
No, since the feeder is protected at both ends, at 200A, you use 705.12(A)(2)(b), not 705.12(A)(2)(a). You don't need to use PCS. There is no way that feeder can carry more than 200A.

On the drawings, they should change the name from line side tap to load-side feeder tap, or similar.

They should also have the Enphase meter collar on the dwg, for use as the MID to diconnect the grid. You didn't mention it so thought I would ask. It is required for backup functionality.
 
solarken said:
No, since the feeder is protected at both ends, at 200A, you use 705.12(A)(2)(b), not 705.12(A)(2)(a). You don't need to use PCS. There is no way that feeder can carry more than 200A.

On the drawings, they should change the name from line side tap to load-side feeder tap, or similar.

They should also have the Enphase meter collar on the dwg, for use as the MID to diconnect the grid. You didn't mention it so thought I would ask. It is required for backup functionality.
Click to expand...
Ahh got it. Yes, they do have the meter collar. Thanks for the help!
 
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