Remote inverter connection to utility wiring question

[garykirk]

I have 3 Sunnyboy inverters (2 6000US and 1 3000HFUS) connected to my ground mount array located 150 ft. from my service entrance. At the present, each inverter is connected separately to breakers in an AC combiner/disconnect panel located near the service entrance. My question is this... does it make any difference whether the combiner panel is located near the inverters, and one 3 wire Cable (with a ground) is run from the panel to a disconnect switch near the main, or as it is presently wired with 3 sets of wire running from the inverters to the panel near the service entrance. Since profession installers see this section I thought I would seek opinions on it. I also would be interested in wire sizing comments... At the present, the 6000 units (25 amp max) are connected with #6 wire and the 3000 unit (12.5 amp max) is connected with #8 wire. When I look at wire company sizing charts, or do my calculations using the formula in my Photovoltaic Installation guide, it looks to me that for 150ft the wire sizes should be #4 and #6 respectively. My installer thinks these sizes should be fine. I am concerned about the difference in AC voltage I see at the array vs. at an outlet in my house. It is on the order of 3 to 3.5 volts when the array is at 85% of maximum output. My house voltage rises from 123 to 126 volts at the same peak production time. I also see AC voltages differing by as much as 2 volts measured at the inverters. Should I be concerned about any of these issues?

[Naptown]

On long runs I always place the inverter(s) close to the service on the house or building not at the array.
2 reasons for this
1 The DC is generally at a higher voltage lower amperage and the voltage drop is less.
2 With remote inverters you can get voltage rise at the inverter Which you are seeing, to the point of the inverter tripping off line.

[garykirk]

On long runs I always place the inverter(s) close to the service on the house or building not at the array.
2 reasons for this
1 The DC is generally at a higher voltage lower amperage and the voltage drop is less.
2 With remote inverters you can get voltage rise at the inverter Which you are seeing, to the point of the inverter tripping off line.

We had a tripping inverter on the initial installation.... It has since been replaced, but that is exactly why I was concerned with the way it was installed... I will speak to my installer about rectifying the situation, but do you think the wire they ran for the AC will be ok voltage wise for 380v dc? Thanks for the quick reply by the way!!!

[Naptown]

All commercially available such as is used in house wiring other than low voltage wire used in the US is rated for 600 Volts so it should be OK insulation wise.