connecting array wired by others

[maffa ent]

we're gonna be doing the ac work, and possibly connecting strings at inverters, on systems where other contractors will be installing the modules, and feeding cables through to us. or they may already have fed the cables through to inverter location!

how can i be certain i'm observing correct polarity when connecting the string cables?

 

[JulianC]

Voltmeter

 

[maffa ent]

ok! so, if positive probe from voltmeter is on cable marked positive from string, and negative probe from voltmeter on cable marked negative from string, and reading is for example 200v dc, then i can confidently connect positive string cable into positive input terminal on inverter, and negative string cable into negative input terminal?

and if voltmeter indicates -200v dc, then they've marked them up wrong?

and............if they're not marked at all, am I on the right track?

 

[JulianC]

Correct. The polarity of the voltmeter reading will tell you what's what.

 

[Earthstore]

Take care, high volt DC bites...

 

[maffa ent]

thanks for the replies, and i'll be careful!

 

[moggy1968]

the safest way is to stick your probes in the terminals on the in side of your DC isolator.
don't try and test the current this way though, you'll get a very big spark, don't ask me how I know!!:blush2: