electricaljunction-box
I've got a surface mount box mounted to the drywall. I now want to run an outlet to the adjacent room on the other side of this wall, but not directly lined up with the existing box.
Is there any problem with knocking out the knockout pointed to by the green arrow and just drilling a hole in the drywall big enough to fit the MC connector and then running the MC to a flush mount box on the other side of the wall?
The fixture itself is typically used as the junction box. Just make sure to use a bushing or grommet to protect the cable where it enters the fixture. These Push in grommets are useful for this.
There are collar boxes available that have conduit KO's (knockouts). Just install one on top of the existing device box and run your conduit.
This one is even better as it has more volume:
Brand: Steel City, Part number:531511234UB
Here is a raised device cover to be used with the 4x4 box shown. They can be had in any number of different configurations.
Best Answer
It appears that there's a screw just to the left of your green arrow that holds the box to the wall. If that screw is centered on the stud, then it's likely that the stud will actually be blocking both knockouts to the left and right side. i.e., you could get the knockout out, but there may not be enough room for the connector or conduit.
If that's the case, you'd want to go with a knockout on the right side of the box, directly into an elbow pointed at the wall. Run your conduit through the wall at that point, then decide if it's going to go into the back of a box on the other side or into the side like this one.
Other than that (and ensuring you don't exceed fill limits), there should be no problem with your desired method.