Enphase IQ Combiner 4C - 3 branches vs 4 branches

[bbajay]

I'm installing 28 panels + IQ8H microinverters in 4 rows x 7 column pattern.

I have an Enphase Combiner 4/4C which feeds into a 60 amp solar breaker in the nearby main panel.

I want to run 4 branches each with 7 inverters, each into a 20 amp breaker in the Combiner 4/4C.
Instead the vendor recommended to run 3 branches, with microinverters on branches as follows:
branch 1 with 10
branch 2 with 10
branch 3 with 8

==> Is there any reason not to run 4 branches each with a 20 amp breaker into the Combiner 4/4C?
( I'm fine to pay for the extra 20 amp breaker and additional branch wire from the panels, so not worried about that).
e.g. Does the cell modem in the Combiner 4C need one of the 20 amp breaker slots ?
Or any other reason not to run 4 strings (other than costing one extra breaker + wire)?
Thanks,
Al

 

[zanydroid]

Interested to see what people with more experience have to say…

One potential issue is that there are subtle differences between two ways of counting energy sources. Some parts of the code uses the output nameplate rating of the microinverters (this is the better one overall, because it’s more accurate and AFAIK more in your favor). Others use the breaker size.

So if you run into a relevant code section that counts power sources by breakers, in the four breaker case you have to count 60A of solar breakers and in another 80A.

Also even if you apply the code right, it is possible for plan checker to get confused and count it by breaker when you are actually allowed to count by nameplate. Which will delay your project.

If Enphase micros are listed for 15A circuits and 7 microinverters total to 12A AC or less, you might consider using #12 wire into four 15A breakers (for efficiency and opportunity to expand).

 

[kendive]

I'm installing 28 panels + IQ8H microinverters in 4 rows x 7 column pattern.

I have an Enphase Combiner 4/4C which feeds into a 60 amp solar breaker in the nearby main panel.

I want to run 4 branches each with 7 inverters, each into a 20 amp breaker in the Combiner 4/4C.
Instead the vendor recommended to run 3 branches, with microinverters on branches as follows:
branch 1 with 10
branch 2 with 10
branch 3 with 8

==> Is there any reason not to run 4 branches each with a 20 amp breaker into the Combiner 4/4C?
( I'm fine to pay for the extra 20 amp breaker and additional branch wire from the panels, so not worried about that).
e.g. Does the cell modem in the Combiner 4C need one of the 20 amp breaker slots ?
Or any other reason not to run 4 strings (other than costing one extra breaker + wire)?
Thanks,
Al

First off why are you getting the Cell Modem? Are you getting Enphase batteries also. You did not mention that.

In the AC Combiner there is a spot for a breaker in the center to power the Envoy.

If you are getting batteries that breaker that powers the Envoy in the AC combiner will get moved to the IQ Controller.

If it was me I would run all four strings with 12/2 to the AC combiner unless you plan to add more panels in the future.

 

[zanydroid]

Others use the breaker size.

I looked at the data sheet and instructions for the combiner and it should be good up to 80A of power source breakers and 64A of inverter output.

So I don’t see a problem with how you want to configure it for solar only situation. I would be worried about storage though since there is no breaker for it and it might put you over 80A/64A once you add the solar and storage together.

 

[bbajay]

Interested to see what people with more experience have to say…

One potential issue is that there are subtle differences between two ways of counting energy sources. Some parts of the code uses the output nameplate rating of the microinverters (this is the better one overall, because it’s more accurate and AFAIK more in your favor). Others use the breaker size.

So if you run into a relevant code section that counts power sources by breakers, in the four breaker case you have to count 60A of solar breakers and in another 80A.

Also even if you apply the code right, it is possible for plan checker to get confused and count it by breaker when you are actually allowed to count by nameplate. Which will delay your project.

If Enphase micros are listed for 15A circuits and 7 microinverters total to 12A AC or less, you might consider using #12 wire into four 15A breakers (for efficiency and opportunity to expand).

Appreciate the comments. I was also a bit worried that someone might look at 4 20 amp breakers and somehow think I'm backfeeding 80 amps. ( Panel limits me to 60 amps). IQ8H-240 has a max continuous output current rating of 1.58A. So a string of 7 would have a max continuous output rating of 11.06 amps. So I assume using 15 amp breakers would be ok.

 

[bbajay]

First off why are you getting the Cell Modem? Are you getting Enphase batteries also. You did not mention that.

In the AC Combiner there is a spot for a breaker in the center to power the Envoy.

If you are getting batteries that breaker that powers the Envoy in the AC combiner will get moved to the IQ Controller.

If it was me I would run all four strings with 12/2 to the AC combiner unless you plan to add more panels in the future.

Appreciate the input. I don't plan to add more panels and I don't have any battery and also I'm fine with wifi only.

 

[bbajay]

I looked at the data sheet and instructions for the combiner and it should be good up to 80A of power source breakers and 64A of inverter output.

So I don’t see a problem with how you want to configure it for solar only situation. I would be worried about storage though since there is no breaker for it and it might put you over 80A/64A once you add the solar and storage together.

tnx!

 

[kendive]

Appreciate the input. I don't plan to add more panels and I don't have any battery and also I'm fine with wifi only.

Yea you don't need that stinking cell modem. Are they trying to sell you that?

 

[zanydroid]

once you add the solar and storage together

I looked at the diagram for where the AC coupled battery feeds in in an Enphase system and it is not on the AC combiner panel.