One showed up damaged....there was no sheet showing where the power cord comes out the back so installing the outlet before it arrived was impossible to accomplish. 

The manufacturer was of zero help.

I will post pics of where the cord comes out the back....that said the back is screwed on and can be cut easily for rerouting the cord.

So as long as the outlet is behind the mirror you will be good....the outlet will need to be recessed to keep the mirror flush with the wall unless you cut more of the back out of i to allow the plug to recess into the mirror box.

Very poorly designed for such an expensive item....an inexpensive few punch outs in the back would make it much easier to install for penny’s per unit.