I want to install an outlet in between two garage doors. I am wondering if there is something in NEC which either explicitly prohibits, or forces to treat, an outlet in this location as an external location.
Reasoning - during heavy rain and windy conditions if doors are opened then some water might get inside.
Right now I'm planning to use Legrand Wiremold 700 series.
No nothing special that is a normally dry location as identified by code. All garage receptacles do require GFCI protection so either a GFCI breaker or GFCI receptacle is required.
I would consider a WR (weather resistant) rated receptacle as they last longer in garage locations.
What Ed says.
You are not grandfathered on GFCI protection since this is a circuit extension. You need it.
NEC does not require a GFCI receptacle. The difference between "protection" and "receptacle" is very important here. A GFCI device can protect any circuit extension beyond that point.
E.g. a GFCI breaker protects the whole circuit. A GFCI receptacle protects its own sockets obviously... but it also can protect everything on the circuit past that point. That is the only thing the "Load" terminals should ever be used for. Novices often use the "Load" not knowing why or knowing any better; silly problems then follow.
So in your case, use "Load" quite intentionally, at the outlet you are extending off of. Put the GFCI there, then wire this new receptacle off the "Load" terminals of that GFCI. Now it is a plain recep (use WR as Ed suggests) protected by that other GFCI.
If you're going "wow, I could protect all the garage receps by putting the GFCI at the first location"... then you've got it!
The last snag is the "GFCI Protected" sticker. That's mandatory, but the provided stickers are paper and will get wrecked. I recommend using a white cover plate, and a Brother or P-touch label maker to make the "GFCI Protected" label. I recommend the label also says where the reset is found.
GFCI Protected
Reset near entry door
etc.
Oh, one other thing. In surface conduit, no need to wrestle Romex cable. You can use THHN individual wires - black white green are the mandatory colors. Typically sold for about 20 cents a foot. Use solid not stranded. Stranded is a pleasure to work with, but is impossible for novices to attach to side screws on sockets. However, your GFCI will have "screw-to-clamp" back wiring, and if your plain socket does also, then stranded is OK. Better ($3 range) sockets usually have that feature.
Nothing prohibits it. I have outlets between my garage doors. My house was built (and inspected) in 2013.
If there is a chance of water, then I would use a PVC conduit with sweeps attached to a PVC surface mount box. I do not think the metal Legrand wiremold will hold up well with moisture. Metal and moisture and electricity are not a good combo.
Codes here require all garage outlets to be GFCI protected and if there a chance of any moisture in that area I would suggest using a "waterproof in-use" outlet cover.
