For my B727-200 flight deck, I'm using the actual landing gear handle and seven (7) Korry indicators for gear/doors position, which require 28V.
I have an adapter which can provide either 16V or 24V. The 24V setting is acceptable lighting for me so no worries there.

I have an Open Cockpits master card, inputs card and outputs card. These require a 5V input; I have the power supply for these.
Separately, I have several single channel DC 5V coil 10A AC250V/125V DC 30V/28V relay module boards. I found the coding for the gear position lever/switch and lights for use with SIOC but am concerned about the power for this project.

Since the OC cards require 5V to power, am I correct in presuming that with the relay boards, I need to power these boards with the 16V/24V adapter or will this fry and destroy my current OC cards?
In other words, do I need to power the OC boards with the 5V power supply and the relay module boards with the 16V/24V power supply separately?

Any solutions and guidance is truly appreciated.

Thank you all.