Like Hotline, my bible isnt with me,but if Im not mistaken ( which I have been before) MC is ok for cinder filled or placement in old work on masonary walls.(Meaning not EMBEDDED in concrete or masonary) I've also argued the point to an inspector that protection is required all points that pass through or are attached to the building structure within an 1 1/4 inch.This would include studs @ 24 or 16 inch centers meant for drywall or covering, sill plates, and bottom plates. Add a stud for your switch box and it technically doesnt need a nail plate because its not intended for wall covering.This is only an agrumentative point and not a common practice, though. Bottom line is you need to protect your work. The biggest promblem I see in the pic is I dont think the MC can be embedded in the plaster that is going to patch the wall.
