Bonding metallic back boxes. Best practice?

[Mark42]

Something about the way this box is bonded feels wrong. I prefer the box to remain bonded even with the accessory removed. Is this method compliant? What do others think? (Ignore missing grommet)
(Taylor Wimpey new build)

 

[Megawatt]

Does GN3 info always suggest such short T&E cable length in sockets?

Mark if is metal and can be engerized it needs to be grounded

 

[Lucien Nunes]

I think Mark is aiming at a point of very specific detail here. In the UK we have socket outlets with either one or two earth terminals. Historically, for 50 years the convention with a ring final circuit was to connect both legs of the ring to one terminal. Then, a regulation came in that required a high integrity CPC if the expected total leakage on the circuit exceeds 10mA. One advantage of the RFC (and many of our sockets are on RFC's) is that it provides two parallel CPCs which serve the purpose of a high-integrity CPC if they are separately terminated using a dual terminal socket.

In Mark's pic, the socket has dual terminals, not needed specifically as a domestic RFC is not considered a high leakage circuit. But instead of putting the two legs separately in the two terminals, they have put them both in one and used the other for the back box strap. I would say it's fine, but it's a pity not to gain the advantage of the high integrity CPC where dual terminal sockets are installed.