[paolo]

home hardware, torbram electric supply, and if u wanna check the big box stores, try aikenheads or rona.

and BTW, I have installed one of those rectangular electrical boxes that do not require to be secured to a stud, they have clamps that goes behind the dry wall, and when you cut the hole in the dry wall, the "Ears" of the box sits on top of the dry wall, so it simply holds it in place once you tighten the clamp.