I have had this discussion with my colleague earlier. A DC power supply is non-alternating, so the magnetic field a DC power wire generates is constant (is it?). Now, I know the rule is to separate power cables and data cables, but I'm assuming that's when it comes to AC power. Is it the same rule when it comes to a regulated DC power supply?
We are using CAN bus twisted pair wires next to regulated DC power cables (12V and GND). I understand that CAN is immune to noise, but if you had a different data cable (let's say UART aka serial, or Ethernet), would the DC power cables have any impact? If so, why?