I'm wiring up an electrical box that has several sensors, relays and a PLC. The PLC and relays are powered with a 24Vdc power supply. The sensors, which provide an analog input to the PLC, are powered by a separate 24Vdc power supply.
In wiring all this up, I've inadvertently connected the negative terminals of the two DC power supplied together. The positive terminals are still separate. I've traced all the wires back and cannot find a source of the connection.
Is it bad to leave the negative terminals connected? Should I find the connection and remove it?