What colour DC Cable from string back to DC isolator?

[cookiemonster]

I bought an MCS starter kit for my MCS assessment from Segen. All is installer and working OK - or so I thought. I recall reading seeing a previous thread on here over the weekend about the correct colour to use for DC cable. My starter pack from Segen included 100 meters of 4mm double insulated black cable and I have blindly installed my system using black cable for both positive and negative DC connections from array string back to my DC isolator without giving much thought to the fact that there is nothing to distinguish my positive feed to negative feed? Is this seriously wrong? Should I rewire my install and if so in what colours?

Any help would be very much appreciated. Many thanks.

 

[SolarCity]

Don't panic! Just identify each end with insulating tape or something similar. The positive should be brown and the negative should be grey.

 

[cookiemonster]

Thanks Biggs for the solution and such a prompt reply. Funny I was just mulling over in my head whether the insulating tape would suffice so it's nice to have it confirmed. (but didn't know what colour it should be)