Running Electric for an Outside Light

I think I know what I need to get this done, but I also know that there are a lot of folks more fluent in minor details like "code" around here, so you can set me straight if I'm not on the right path.  

I want to add an outside light over the doorway of an older building.  There is a light switch right inside the door that controls an overhead light in the entry way.  I figured that I would take that box out, replace it with a two-gang and add a switch for the external light.  I'd drill a hole through the masonry to the outside and run the romex through PVC conduit, through the hole, and into a box that I'd mount outside on the brick and bolt up whatever light fixture to that box.  Obviously, some caulk to seal up around the conduit.  Am I missing anything here?  Is the PVC conduit okay for that application?  I don't have to replace the breaker with a GFCI one, do I?  It just seems too easy, I must be missing something!

Sounds like a solid plan.  You don't need a GFCI breaker for a light, if you add a receptacle you will need one.  

I would keep all of your wiring inside. Either open up the wall above the doorway and then fish up the wall, drilling through one or two studess to get to the center of the doorway before penetrating the outside wall or come out of the box from the inside light if you are able to, and your joists line up the right wau for it.  Is there an attic above the entryway, or is there a second floor right above it?

Chicago code is much different than yours for residential, so I never have messed with Romex, to tell the truth. 

In reply to Cooter :

It's bare brick inside with the ceiling well above where I need to drill through.  I don't think I can easily get into that wall so I planned to run the conduit up the inside wall and have a weatherproof box right on the other side, so no conduit showing outside.

The only reason I planned to use this type of wire is that I've got about 50 feet of nmb 12/2 left over from another project.  If there's a concern with using that for this application, though, I'd rather buy the right stuff than burn my friend's studio down.

Ahhh.  I thought you were running the raceway on the outside. And assumed drywall on the inside.   I would run 1/2" EMT between the two points, myself. And then pull stranded #12 AWG THHN from the switch to the light fixture.  Mostly because I do commercial work.  And exposed EMT is pretty on brick. #14 would likely be fine, however. 

Would it be smart to add a couple 110v plugs at the same box since you have it apart ?

In reply to Cooter :

If I read things right (big if!), I don't need to de-rate to have 3 12AWG wires in 1/2" EMT, so I might as well.  I'll check the price difference between the 14 and 12, though. We're only talking about a single light fixture with probably 1 but no more than 5 LED bulbs so, what, 8 amps on a really heavy day?  Of course, the breaker should only be a 15 amp, so if there's a big cost difference, I'll consider the 14.

Thanks for the primer!  I hadn't really considered the metal conduit, but I think you're right about how much nicer it's going to look.  Since this will be almost the first thing that people see when they walk in the door, it's probably best to keep it classy.

In reply to californiamilleghia :

Ordinarily, I would be all about putting outlets in. I've never found myself in a room and said "there are just too many places to plug E36 M3 in around here!".  But... this is an area that's MAYBE 15-20 sqft - just enough room to swing the door in and then go up the steps to the second floor.

No need to derate 3#12s in a 1/2” EMT.

I’ve had better luck using “duct seal” than caulk to seal the raceway off.  Caulk is a PITA if you come back later to change things.

5 LED bulbs shouldn’t draw anywhere close to 8 amps.  Closer to 1.5 at the most would be my guess.

I bent the rules a bit when I did the same thing, but your plan sounds solid.  I agree that EMT looks great on brick.  Get a 90 degree corner and no bending needed.  Make sure the outside box is good for wet applications, even if it's under an awning or roof.

When I did mine, I found a spare unused 15A breaker in the box, ran new 14/2wg to an outlet box in the basement (mostly because I had two pieces of Romex that weren't quite long enough to do the whole run with one), then to a surface-mount switch box next to the door.  I ran mine in surface-mount track mostly because I hate bending EMT. From there I drilled straight out and mounted a 1-gang box.  The only non-kosher thing I did was that I ran the SJO cord from my patio string lights inside to the switch.  Running SJO in walls is a no-no, but it was literally 4" straight through the wall with a box on either end.  If I ever sell the house I would just undo that part so it doesn't show up on an inspection.  It's safe, just a technicality for someone who doesn't know it's there.

californiamilleghia said:

Would it be smart to add a couple 110v plugs at the same box since you have it apart ?

I ran an external outlet to run some LED lights and a fish pond pump.  I thought it was buttoned up pretty well but ants got in there, somehow they conga lined from one pole to another and fried, tripping the breaker.  How do you get around that?

Revisiting this for one last bit of advice if you'll indulge me.

I picked up my supplies from the local big box joint and I was able to find 25' rolls of 12 awg THHN in white and black.  Apparently no one sells green in rolls smaller than 50' and I only need about 10-12ft.  The guy in the apron first tried to tell me that I could just use the 14 for the ground. I get that it's probably okay - especially since it's just this one light - but the breaker is a 20amp and I don't see a need to shortcut this.  When I asked him if using a smaller awg was code he said it would be fine and that it would meet his code. Not confidence-inspiring.  Next, he tried to tell me that I could use the white wire and wrap it in phase tape. But I'm reading that doesn't apply for 12awg.

If I understand correctly, if I can't find stranded green 12awg THHN it is permissible to use solid 12awg unjacketed copper for the ground through the EMT, right?  Or do I use the EMT as the ground?  I don't know that would work even if I could since my outside weatherproof box is non-metallic, though.

Using the 14 for the ground is not code compliant as the circuit is rated for 20A. Taping the white wire green is technically not code compliant either but is widely done. The trick is to make sure it is plainly identifiable as green/ground wire anywhere it is accessible. Most box stores will cut the wire to the length you want so you should be able to get the green in the length you want. I don't know that you would be able to get 12 bare any easier than green.  Using the EMT as a ground path would work if all your boxes were metal but where the outside box is non metallic it is not an option and overall is not always a great idea as the connections can come loose and then there is no path for grounding. Remember to land the ground wire in the boxes it starts in, goes through and ends in for proper path. They make green screws that fit a pre tapped hole in the boxes, don't use a sheetrock screw.