Currently I am looking at a 10KW solar install. The plan is to install 2 string inverters (5KW ea.) at the house 350ft away from the panels. This would involve 4 DC circuits at about 355V each. Full load current would be about 8 amps. I plan on using 8 runs of 1/0 RW90 cable (4runs x 2 wires/cct) I figure this would be about a 3.5% volt drop. Additionally this would all go in one 4 inch PVC conduit underground. I have never installed DC circuits of this high voltage before, does anyone have any thoughts or considerations on this setup and on working with high voltage DC circuits?
Greg's right about not getting any AC output until there's a live grid, but the DC from the panels is there anytime that there's light falling on the panels. Watch what wires you touch and you should be fine.
This sort of gets back to the desire for a disconnect right at the collector. I am just not sure what the best method might be. Maybe just a small encapsulated relay as part of each collector with an "enable" line.
I haven't posted for a long time now, but I must comment on the collector panels.
Even the 15 watt suckers can give you a nasty jolt when they are are unloaded. They put out a bunch of volts in direct sunlight at the terminals that can knock you off the roof at the terminals. - I know- I just went through that this week and would up connecting - very stupidly - with the unloaded output with the "tame" voltage from the sunlight panels. I damn near got knocked off the roof by the jolt I got.
"Green is good" for now, but and a big BUT, be careful with these so called "docile" panels.
BTW - anyone have any hints on how to earth these things and isolate them from a grid tie system?