Max length of run?

[Earthstore]

Just one other point, make sure when you install these DC cables that they are secured and safe, they are high voltage DC and the last thing you want is for them to get chaffed.

 

[Gavin A]

thanks gavin. what circumstances are these?

where it's not cost effective or practical to move up to 10mm2 cable. TBH I'd only consider it for bigger systems, never go above 6mm2 on something that size, though I guess I've also never gone above a 66m run for a system that size either.

 

[nick611]

ok gavin thanks. its a case of neccesety im afraid the length of run. and in reply to earthstore cables are run on cabletray and in flexible conduit labelled pv every four meters. thanks lads

 

[Worcester]

Some of our runs have been nearly 200m round trip on 6mm2, though at nearly 1000V (big strings ) Voltage drop is your enemy. As they guys say, Sunny Design is your friend here (it's free) V=IR Voltage Drop = Max Current (Isc) x Resistance (Ohms/m x length in m) Ideally you want as low as possible. At the end of the days it's effiiceincy losses and if cloase to the startup voltage of the inverter will have a bigger impact.

 

[moggy1968]

bear in mind also that the performance of panels diminishes over time, and also voltage drops with temperature so you need to be comfortably above the start up voltage to make sure the system still works in 10 years time and on a hot day!