Wire size and type question

[Junkman]

What type of wire and size will I need to put two 135 watt LED wall packs on my home. The switches are going to be located in a steel electrical box that is set into a brick wall, and has a 3/4" steel conduit going up to a 4" box in the attic. I am planning on installing the two romex wires from the lights into that 4" box, and coming down the conduit with just a hot wire down and one back up to the black wire from the lights. The neutrals will be joined in the box, and all the bare grounding wires will be bonded to the box with a screw. I was thinking that solid wire will be the easiest to get through the conduit from the bottom, or stranded going down from the top.
Thanks Junkman

 

[wyliesdiesels]

If youre connecting this to an existing circuit, the wire size will be dictated by the breaker rating.

 

[Junkman]

the entire house is wired with 12 gauge and 20 amp breakers. If I use 12 gauge stranded wire, how many wires are allowed in the 3/4" conduit. Presently, there are 3 12 gauge wires in the conduit for a ceiling light that is controlled at each side of the room. I will need to add 4 more wires to control each exterior LED light, or I could put them both on one switch, which would eliminate 2 wires coming down the conduit. I prefer them to be seperate, but will do what is necessary to keep this proper.
Thanks Junk

 

[nsula_country]

16, #12.
22, #14.


Ct

 

[nadogail]

In theory you will be able to put enough conductors in that 3/4" conduit, you may find it expedient to remove the existing conductors and pull in the whole package at once.

 

[sberry]

If they are on the same circuity might need to only add 3 wires.