Spacey73 Posted October 9, 2022 Share Posted October 9, 2022 The higher the PV voltage the less strain on the wiring. I’m also in a similar situation where I have a 50m run from PV to Workshop then 15M to Garage where inverters and battery are. I have 3 sets of ground mounted panels (Waiting for the ‘do you have planning permission’ nimby remarks….) that are running at around 430v DC each. Downside is that I have to run 3 sets of 2 cables as I have 3 x mppt inputs on inverters that are maxed out with 12 panels (1 string) so can’t parallel them up. Inverter and batteries are very close to main house distribution box and do a zero export similar to the ct clamp method. It really is best to go DC from PV to house then convert to AC at that point. Modern inverters will take up to 500v to 600v on mppt inputs. 6mm PV cable at 10amps max should give good voltage loss results. Link to comment Share on other sites More sharing options...
Radian Posted October 9, 2022 Share Posted October 9, 2022 1 hour ago, Spacey73 said: AC at that point. Modern inverters will take up to 500v to 600v on mppt inputs. 6mm PV cable at 10amps max should give good voltage loss results. Just curious - 430VDC on 50m x 6mm2 outdoors is testing the cable insulation, do you have it in trunking? Link to comment Share on other sites More sharing options...
SteamyTea Posted October 10, 2022 Share Posted October 10, 2022 9 hours ago, Radian said: Just curious - 430VDC on 50m x 6mm2 outdoors is testing the cable insulation, do you have it in trunking? Think most DC cable for PV is rated up to 1000V, though most are calculated on 600V these days. It may be buried in this old standard. https://www.bre.co.uk/filelibrary/pdf/rpts/Guide_to_the_installation_of_PV_systems_2nd_Edition.pdf Link to comment Share on other sites More sharing options...
Radian Posted October 10, 2022 Share Posted October 10, 2022 53 minutes ago, SteamyTea said: Think most DC cable for PV is rated up to 1000V, though most are calculated on 600V these days. It may be buried in this old standard. https://www.bre.co.uk/filelibrary/pdf/rpts/Guide_to_the_installation_of_PV_systems_2nd_Edition.pdf The problem with just looking at the published insulation rating for the cable is that in real-world conditions, distributed moisture absorption over the length of cable creates a leakage current that may trip the ground impedance detector in a transformerless inverter. The higher the voltage and the longer the cable, the greater the accumulation of leakage current. Link to comment Share on other sites More sharing options...
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