What is this method called?

I live in a 900+ sq. ft. unit on the 3rd floor of a 100+ year old courtyard building. A load bearing wall runs down the center. Think 2 rectangles attached on their long axis.

I need to run EMT on each side of the load bearing wall to the junctions where the light switches will be. By thinking is I want to make a gutter. But, I am not sure this is what it is called and so I’m having a tough time looking for advice.

What I’m calling a gutter are studs of that sticks out approximately 4” from the wall and is 6” wide. This is to accommodate a triple-gang for room, hallway and fan switches.

What is this structure called? And any recommendations for how it’s built? I was going to frame it with three 2x4’s six inches apart.

This isn’t a load bearing wall question. I’m closing off an already open space. I’m just trying to figure out how much space I should make for EMT to come down each side of the wall to the light switches and whether I should opt for less “gutter”. 2” out from the wall? Three?

Edit: sorry for the typos. On my phone. If the studs on one side of the wall were drawn with x’s, what I’m trying to describe is this:

X

X

XX

XO

XX

X

X

The “O” is the EMT and the junction.