Andrew G wrote:
[Also note that this now has to be in a metal enclosure (or the whole
lot installed in a fireproof enclosure). A metal enclosure containing
the first RCD in a TT system needs to have enhanced insulation of the
supply wiring leading in to the RCD, as that's not protected by the
RCD (in effect, it needs to meet double insulation standards). You can
buy enhanced insulation kits for some metal enclosures but not others,
so you will need to make sure you choose one for which an enhanced
insulation kit is available. ]

So not the £2.88 enclosure advertised with the 100 ms RCD at
https://www.tlc-direct.co.uk/Product...7ZwaAifH8P8HAQ

this one?
Insulated Enclosure (Rcd) IP65 Weatherproof
WY WBE4 Insulated Enclosure ( RCD ) - IP65 £21.24
https://www.tlc-direct.co.uk/Products/WYWBE4.html

But maybe as I started years ago (and notified Building Control) under the red on site guide I could use the cheap plastic box not metal?