Just a quick post about a question that is often asked…
“Do I need to earth the metal back box for a socket?”
A metal back box for a socket would be classed as an exposed-conductive part and as such it needs to be earthed. If the back box has a fixed lug on one side then the answer is that it will become earthed via the mounting screws as the socket front is attached to the back box.
This is because of the metal strip that is on the back of the socket that links the earth terminal to the fixing holes to the metal back box fixed lug via the metal 3.5mm screw.
So providing that the back box has a fixed lug and metal screws then it will be earthed when attached to the back box. However it’s still considered ‘best practice’ to add a link from the socket earth terminal to the back box earth connection.
TIP: When you are completing a first fix make sure your double back boxes have the earth connection at the bottom of the back box, as it makes it easier to connect the link when second fixing. Plus with single back boxes make sure the adjustable lug is on the side. if not then “Do your own second fix and don’t ask me!”
Sorry just reliving an old pet hate…
Cheers
Paul