The chief consideration is, that whist it may be possible to run Band 1 and Band 2 cables in the same containment if insulated to the highest voltage present, the terminations need to be in a separate enclosures, because otherwise, when sheathing is removed, requirements of SELV/PELV (Reg 414.4.1) as required for Ethernet and Power over Ethernet, and other data solutions, are not met. Somehow, the backbox would need to have a protective physical separator between both halves (and I guess that's not really designed into Euromod etc.).

The 2×1g (sometimes termed '1+1 gang' or 'dual-gang') backbox is perhaps the obvious solution, with one side a standard 1g single socket-outlet faceplate and the other side a matching 1g data faceplate ... but of course that's slightly wider than a 2g/"double-socket" size modular faceplate.

I also had in my mind a solution with a 4-slot Euromod, socket-outlet on one side, then blank, then RJ45 ... and then fit a separator under the blank (easier perhaps if it's a metal backbox as a metal separator could be riveted in). But I guess that would be "non-standard products" from a BS 7671 conformity perspective, and you'd need to look but I guess some manufacturers' instructions wouldn't really cover you for "mixing" like this, recommending separate "backbox" (or 2×1g).

Syncbox seem to do a product that's similar to the sort of thing perhaps you're talking about, but the backboxes don't appear to be aligned with BS 4662 (and perhaps one or two other questions t be answered about the approach, being "recessed") ... but it does look like there is a plastic separator between the two "sides" of the backbox, that goes the whole height behind the faceplate.

(Another issue is that, at the moment, BS 6701 within buildings requires a minimum of 50 mm physical separation between data installation cabling and mains installation cabling, even if there's an earthed metallic separator ... but that's a whole other discussion item.)

Thank you for your response, you confirmed my concerns.

Some manufacturers do produce dividers for BS 4662 back boxes  - e.g. MK's 888ZIC (at least for twin boxes).

  - Andy.

AJJewsbury said:

Some manufacturers do produce dividers for BS 4662 back boxes  - e.g. MK's 888ZIC (at least for twin boxes).

Yes, as you point out that won't sadly do exactly what the OP wanted, as it's for the 2×1g box, which is for two 86 x 86 mm faceplates, not an 86 x 147 mm ("double" or "2g") faceplate ... and perhaps wouldn't be compatible with a 4-module 86x147 mm Euro modular faceplate?