I am in the process of installing a small solar array and ran my panel to charge controller cable through pvc - trouble is, I did not mark either of my two identical cables before pulling them through and now it is impossible to tell one from the other. This is 25' of large heavy cable that would be a long days work to take down, dismantle and mark it before re-assembly and remounting on my roof - so I'm hoping someone can tell me how to tell which cable is which.
I'm thinking I can hook up both cables to my panels on the roof and use my multi-meter at the other end to see test which is positive and which is negative. How would I use the multi-meter to test for polarity?
Thanks to all you smart people at there!