I would like to add 3 new 20 Amps outlets in my unfinished basement. I'm going to run some NM-B cable along the ceiling joists and I will use metal boxes attached on the concrete walls as well as use EMT conduit to protect the cable from the receptacle to the ceiling.

If I decide to cable my receptacles in a row using the terminal screws (vs pig tail), can I run the 2 cables from the middle outlet in the same conduit or do I need to run 2 conduits? If yes is there a minimum acceptable diameter to do so?

  • You're running cable along the ceiling, down the wall to a box, then back up the wall, across the ceiling, and down the wall again to another box? Why not just put a junction box on the ceiling right above the receptacle, and just run one cable down the wall? – mmathis Jul 27 '17 at 20:39
  • Yeah, we just did this exact question last week. They should be merged. – Harper - Reinstate Monica Jul 27 '17 at 23:29
  • Thank you all, I searched before asking :-( guessed I didn't search hard enough. – guillaume.molter Jul 28 '17 at 15:43

There is no Code requirement to pigtail the receptacle hot and neutral unless you are using a multiwire branch circuit. (A circuit with multiple hot wires) Even then, the requirement is that removal of the device cannot break the neutral so the neutral has to be pigtailed but not on a two wire circuit.

300.13 Mechanical and Electrical Continuity — Conductors.

(B) Device Removal. In multiwire branch circuits, the continuity of a grounded conductor shall not depend on device connections such as lampholders, receptacles, and so forth, where the removal of such devices would interrupt the continuity.

There is a Code requirement to ground the receptacle in such a way that it does not break the equipment ground. Either you can use self grounding receptacles or you can pigtail the ground.

250.148(B) Grounding Continuity. The arrangement of grounding connections shall be such that the disconnection or the removal of a receptacle, luminaire, or other device fed from the box does not interfere with or interrupt the grounding continuity.

Ok all that said, you don't need to ever have two cables in a conduit unless you plan to run two circuits. You cloud then conceivably have two cables protected by one conduit and with 12/2 that you would need for 'a 20 ampm circuit I wouldn't try that in anything smaller than 3/4" EMT.

Good luck and stay safe!

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