Mixing grid-tie inverter types

[HOASUNBuster]

Well now, I am pretty pleased that I have managed to get my system installed and running over the last year and have added panels till I can add no more. My Power one 2KW string inverter is maxed out and only has one string input. Without adding another power one 2KW and joining them internally as they are set up to do or doing a wholesale 2 input swap, is there any reason why I couldn't add a string of Enphase onto the same breaker panel ( different breaker) in parallel with my current system? has anyone done this successfully or would they end up fighting each other to get power into the panel. Would this compromise the anti-islanding? I know the enphase are a string of small inverters all on the same circuit but they are all the same and made to work like that. Looking for some wisdom from the more experienced Solarbabies.

[inetdog]

Well now, I am pretty pleased that I have managed to get my system installed and running over the last year and have added panels till I can add no more. My Power one 2KW string inverter is maxed out and only has one string input. Without adding another power one 2KW and joining them internally as they are set up to do or doing a wholesale 2 input swap, is there any reason why I couldn't add a string of Enphase onto the same breaker panel ( different breaker) in parallel with my current system? has anyone done this successfully or would they end up fighting each other to get power into the panel. Would this compromise the anti-islanding? I know the enphase are a string of small inverters all on the same circuit but they are all the same and made to work like that. Looking for some wisdom from the more experienced Solarbabies.

Since each string or micro inverter is independently managing its relationship to the power grid, there should not be any compatibility problems. And anti-islanding which is compliant with UL standards should not have a high risk of one GTI or set of GTIs effectively simulating the grid for its neighbors.

I would not worry about it.

I would look at the breaker placement in the panel and the details of the 120% rule before saying that adding to the system as you propose would not be a problem.

[HOASUNBuster]

Since each string or micro inverter is independently managing its relationship to the power grid, there should not be any compatibility problems. And anti-islanding which is compliant with UL standards should not have a high risk of one GTI or set of GTIs effectively simulating the grid for its neighbors.

I would not worry about it.

I would look at the breaker placement in the panel and the details of the 120% rule before saying that adding to the system as you propose would not be a problem.

OK, with my current setup, I have a 15A dual poll breaker and at peak am currently feeding less than 9A/240V to the bus bar. What you are saying with regards to breaker placement is not to overload any one section of the bus by placing 2 or more high current circuits next to one another to allow heat dissipation along the bus. At only 8.75A, I don't think I am in an over heating situation on the bus but the 15A breaker is right next to the dryer breaker. If I added more now knowing about the 120% rule, I would certainly rearrange things in the panel. I also saw a post stating placing the solar feed at the opposite end of the power feed from the grid. That makes some sense to me also.

[inetdog]

OK, with my current setup, I have a 15A dual poll breaker and at peak am currently feeding less than 9A/240V to the bus bar. What you are saying with regards to breaker placement is not to overload any one section of the bus by placing 2 or more high current circuits next to one another to allow heat dissipation along the bus. At only 8.75A, I don't think I am in an over heating situation on the bus but the 15A breaker is right next to the dryer breaker. If I added more now knowing about the 120% rule, I would certainly rearrange things in the panel. I also saw a post stating placing the solar feed at the opposite end of the power feed from the grid. That makes some sense to me also.

Actually, what I am saying is that if the total of the main breaker feeding the panel and the sum of all of the backfed breakers (not the sum of the actual inverter currents unless you are in an area which has already adopted the 2014 NEC) is greater than the actual bus rating of the panel (Which might be 125A for a 100A panel or 225A for a 200A panel) you are subject to the 120% rule instead.
The 120% rule requires that all of the backfed breakers must be clustered at the opposite end of the bus from the main breaker, so that all load breakers (both branch and feeder) must be located between them. And the total of backfed breakers and main breaker cannot be more than 120% of the bus rating.
With a 100A bus in a 100A panel, your current 15A double-pole breaker would leave you with only 5A of breaker size for additional PV. So that particular configuration would not fly, with no 5A breakers being made for the panel.