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Posted By Topic: Neutral and Earth on same stud

greensleeve
Sep 10 2019 21:48

When doing work on an older house and you come across neutral and earth on same stud with nut and locknut. I know that it still complies under ESR 113 but does anyone change it to current standard ie for best practice. And if so does separating the earth and neutral classed as high risk and require inspection?

Thanks
   

AlecK
Sep 11 2019 08:20

upgrading to separate the N & E connections involves installing an MEN link.
An MEN link is one of the 3 items that together comprise a 'main earthing system"; and installing or altering (as against simply replacing) any part of a main earthing system is classified as high risk PEW.
So, yes, an inspection is required.

Such upgrading is generally necessary when adding any new circuit, because it's not permitted to connect earth conductors to an N-bar or neutrals to an E-bar; they have to go on separate bars. There is a workaround, by connecting PECs to the MEC (without cutting the MEC); but good practice is to just do the upgrade.


   

Satobsat
Sep 13 2019 14:10

What about when there are separate earth and neutral bars with a link but the MEC is till on the same stud as the main neutral? I would think that this comes under alteration so would be high risk.
   

AlecK
Sep 13 2019 15:26

The rules have changed gradualloy6, so whether it would have required inspection depends on when it was done.

But for new work under today's rules adding altering an MEN link is high risk "mains work"
Same for MEC, or electrode.

Whereas repairing / replacing any of this is still mains work; but only low risk.

But if adding an E-bar (eg for new subcircuit PECs), you're technically not affecting / altering the existing earthing of mains PEN, so not mains work.
And nothing forces you to move that old MEC from n-bar to e-bar; though if you do you must install a link and both actions will be high risk 'cos they alter the basic safety set-up of the installation