I want to build an outlet that I can control on a timer or through a device like a smartphone. I am planning on using a solid state relay for this job. I'm aware of the electrical code stipulation that all low voltage and high voltage wires must be separated by a permanent barrier, as explained in this question. I was going to use a double gang box from home depot like this one to accomplish this. My question is, with the separator there, how do I connect the relay to the low voltage control?

1 Answer 1


You can mix Class 2 conductors with power conductors in boxes if the power circuit conductors are introduced solely to connect to the equipment connected to the Class 2 circuit.

Class 2 circuits voltage and current limits are well-defined by National Electrical Code (NEC.) Also, NEC defines spacing between the class 2 conductors and power inductors.

See NEC article 725 for more.

  • Let's say someone has a 5VDC microcontroller driving the 5VDC control line of solid-state relay that switches on/off 240V/5A to drive the coil of a remote contactor. The microcontroller is powered with 9-12VDC (regulated down to 5VDC onboard). Does that mean that #12 wires @ 240V/5A can be brought the same junction box area that has the 9VDC-12VDC powered microcontroller and also the 5VDC triggered solid state relay, so that the solid state relay switch the 240V on/off?
    – clearlight
    Nov 2, 2018 at 5:16

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.