Electrical – Outlet grounded by conduit – how to add a second outlet with Romex

conduitelectricalgroundingreceptaclewiring

I tested the outlet with an outlet tester which states that it is properly wired. However, I know that conduit is not necessarily always sufficient to provide a proper ground. So I tested the outlet with a multimeter. I get 120.5 volts when testing the line and neutral, as well as when I test the line to the ground hole on the outlet. So it seems that the conduit is properly grounded.

I need to add an outlet nearby this outlet… but how do I properly tie in a romex cable to this situation?

Unrelated but similar question:
I also have several outlets that are not grounded outlets. However, if they are run through conduit that is properly grounded, I might switch out the outlets… But should I instead be rewiring everything? We are closing up the attic floors as we create a master suite in the attic. Seems like the next few months is my last good chance to rewire anything… but I'd rather just switch out the outlets as the time and money invested on that does not seem worth it.

Thanks!

Picture of outlet, box and conduit

Best Answer

If the box is grounded by the conduit, you can get self tapping grounding screws and screw one into the hole in the back of the box. Then wrap your ground from your NM cable around the grounding screw and tighten. Use the proper NM to box connector. Make sure you're not in an area that requires conduit. In my humble opinion, the wiring shown in the lower box should be replaced if you're in a position to do so. It's old and will start breaking up if you mess around with it. As far as the grounding goes, if the box is grounded, you can replace the outlets with self grounding outlets and they will get grounded when screwing them into the box, or you can add a grounding wire to the box and attach it to the outlets.