On Friday, July 12, 2013 1:01:12 PM UTC-7, TomR wrote:
I have a dedicated 15-amp circuit in an unfinished basement that runs to an

outlet on the wall for the sump pump. The wire/cable that goes to the

outlet is white 14/2 NM-B w/ground. From the ceiling down to the outlet it

is fed inside of metal EMT conduit. I assume that the metal conduit is

1/2-inch (the outside diameter of the conduit is about 3/4-inch).



I would like to add a pull string ceiling light above the sump pump for

better lighting while working on the sump pump and/or the HVAC which is next

to the sump pump.



What I am thinking of doing is getting power for the light from the outlet

and running new 14/2 NM-B w/ground from the existing outlet back up through

the same EMT metal conduit to the new ceiling light.



My main question is, is it okay to have two 14/2 NM-B w/ground cables inside

a 1/2-inch EMT metal conduit?

You can’t have any NM cable inside a conduit.
It has to be single conductors.