I am in the process of purchasing a grid tie system. I was doing some calculations and I cant figure out how to set up a system using the Sanyo HIP-190 BA3 PV Panel and the Xantrex 3.0 GT inverter using 16 panels. The Xantrex string calculator shows a 4 string 4 panel grid as not having enough power to run the inverter on hot days 95 degrees (188 Vdc) and no longer has the option to run 8 modules which appeares to generate too many volts (610 Voc x #of series modules * 1.13) NEC 690.7 I would like to use 16 panels for my system using two pole mounts, am I using wrong numbers, how can I make this work?

I'm not a NEC 690 expert, but 8 panels in series using the Xantrex String tool works. Even at 14F would be a VOC of 588, a bit on the high side, but VOC is the no load case ( no current ) and in reality, the GT puts a small load on the PV always which would limit this a bit.

I'm not aware of any multipliers for Voltage in the NEC, its current that has this as one has to account for edge of cloud effects, but again, I don't have and have not read all of the 690 requirements

If the GT can't do it, nothing can, as the GT has the widest input range of any inverter on the Market