QUOTE(advocado @ Jan 3 2018, 12:04 PM)
so how to prevent digging too deep and the box end up sitting too inside? and how to secure the black box in position after putting in since unless you use a Box Sinker the hole won't be just fit.
and to cut a hole all the way from existing, do i need to take out existing box because it's in the way?
also have you seen box sinker locally? i can make a nice square hole very fast instead of drill+hack.
Like I mentioned before, it does not matter if a bit deep or close to wall surface. The screw will just pull the socket front panel snug to the wall. What you cannot see inside the hole is that there are gap between the mounting box and the socket panel. It is normal. They are not designed to be closely fit together anyway.
This is why I mentioned before the screws that hold the socket panel in my house have different length from one socket to another.
Opps. I forgot to mentioned that the screw that is used to screw the socket facet panel is not the screws that are provided with the socket, but rather normal screw that bought from shop. The screws that comes with the socket are machine screw
but the contractor use the self taping screw
Self Taping Screw
Like I said the black mounting box is normally nailed to the wall brick before the wall is plastered or tiled. These black plastic box is not rigid plastic. It can be easily cut with blade knife. So, no need to remove anything. Just hack the wall, elongate the existing hole to the right or left. Just make sure the hole is not too big that it will sink the socket facet inside the whole. As for the holding black box inside the hole, you can just nail it with concrete nail or just use epoxy. Cut a slot between the box to route the wire. The plastic is quite soft.
Don't worry much if it is not perfectly align next to each other or to the socket panel. The screw will just pull the socket facet to the wall and just align the socket before tightened the screw. The wall friction will hold the socket in place just nice.
First time I learn about box sinker
. Never use one. Anyway the wall brick is normally cement type and easy to chisel