Reqirement to join V- outputs of multiple power supplies

[nato595]

I believe I understand the requirement is to join (with a jumper wire of sorts) the V- (negative output) of multiple power supplies. If this is true, and I have a power supply and pixel controller on one side of the yard that power the start of a string of nodes, then another power supply 15 feet away that inject power into the pixel string, do I still need to run a 15 foot cable between the two power supplies just to connect the V- outputs?
I believe I also have to splice the pixel string negatives together so they are both basically connected to both power supplies?

Thank you in advance!

I never claimed to be an electrician, I just like lights!

 

[BundyRoy]

Nato, my understanding is that if it closer to join the negatives at the lights then this is fine and you don't then have to worry about running the "jumper" cable straight from 1 PSU to the other. As long as the negatives are connected somewhere in the wiring system it is fine.

So basically you can join the negatives at the PSU's or at the pixels. Doesn't have to be both as far as I know.