I agree with Monte, keep the relays close to the what it's triggering, with that said, I use the Relays on my ARC switch panel to trigger another a relay close to what it's running

FP in the back pulling power off the battery, fan, water pump in the front. I really like using Leash Electronics small relay boards, they are fused and easy to wire in.

All my signal wires are either twisted pair or Shielded Tefzel wire

All my grounds go to a couple isolated lugs that are grounded back to the battery.

When sizing what ga wire to use, include the length of the ground.

Panel before it was finished.