Plugging 32mm knock out in CU

[JohnW2]

If the centre bolt is tightened fully it will pull the centres together and should prevent them moving under all but the most hardest of knocks. I would be worried if someone was doing something near a CU that could, potentially, have enough force to knock it off the wall.

Quite so - that's essentially what I was saying/suggesting.

Regarding the earthing, I don't really see the need as the CU casing is probably painted inside and out anyway with just the standard earth point as the means to earth the unit.

I did add "...at least in theory" to my comment about the earthing . However, staying with that "in theory", if the paint were all intact, such that the washers were not in electrical continuity with the case, then it would ('theoretically') not be impossible for some live conductor inside the CU to come in contact with the inside washer and/or nut/bolt, thereby rendering the outside washer 'live'. Someone touching that and also some nearby earthed object (pipe, earth block/MET or whatever) could therefore get a shock.

However, the probability of that sequence events happening is obviously incredibly low (quite probably less than the possible incredibly small risk of dying as a result of having AZ Covid-19 vaccine!), so I definitely wouldn't loose any sleep over it in the absence of explicit earthing of the earthing (even if I used this method of blanking, which I probably wouldn't).

Kind Regards, John

 

[JohnW2]

Totally agree with you, they are compliant yet you can argue that they’re not! It’s a complete mine field. I tend to use/suggest them as you don’t need to open the consumer unit to fit them and they are better than a gaping hole at least.

As you will realise, I agree. Particularly give that almost everyone uses plastic glands for cable entries into metal CUs, I would not hesitate to use plastic blanking plugs/whatever - and leave others to argue about whether or not they (and the glands!) are 'compliant'!!.

Kind Regards, John