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Posted By Topic: MEN at Switchboard

MT8262
Sep 30 2018 17:56

Have just looked at a job where a meter box is on the side of the garage, switchboard on the other side of garage with a main switch for garage sub-circuits and main switch for sub-mains to house. In the main switchboard at garage there is a neutral bar and earth bar but it is not MEN. Am I ok to add an MEN link at this junction when installing the two extra circuits? The place would probably be about 30 years old.
   

MT8262
Sep 30 2018 19:41

Really what I'm looking for is the appropriate reg.Struggling to find anything that stands out
   

AlecK
Oct 01 2018 09:05

Under all the sets of Regs since "forever" the first switchboard has had to be MEN. 30 years ago would have been 1976 Regs.

To bring into into compliance now, you'll need to install an MEN link. FTR, that switch in the garage for the house is not a "main switch" it's a submain isolator. Calling it a "main switch" is the sort of incorrect terminology / sloppy thinking that leads to people doing silly things - as obviously happened on this site 30 years ago.

I take it that the submain doesn't have its own overcurrent protection. As long as its adequately protected by the supply fuse, that's OK. Otherwise you need to fit an overcurrent device; either end of the submain will do, as with overcurrent for garage final subcircuits the garage end is already a "switchboard".

The bit that could be tricky is if there's a controlled circuit for eg water heating by 2nd meter / register, that is set up as "common neutral"; if so 2.2.1.2 applies.


Assuming the house is in a separate structure, you can apply the "outbuilding" provision [5.5.3.1 (b); need to check all the conditions that apply but likely OK. Installing the MEN link is high risk PEW, so inspection needed.

If in same structure, that option is not available and you'll need to install a PEC for the submain to house DB, and remove the N-E link from the - and remove the N-E link that is probably there.
   

MT8262
Oct 01 2018 11:28

Thanks heaps Alec. Awesome feedback as always.Cheers