Double-cable CU entry glands?

29 Mar 2005
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United Kingdom
Is it possible get products like this, but with an insert that allows for two 2.5mm T+E cables?

We have 16 circuits. I want to install a Wylex NMX 16 way main switch CU (I already have all of the mini-RCBOs) but the cable entry needs to be at the top of the CU because of where the access is, and if I'm going to use one gland per cable there won't be enough space to accommodate all of the cables.

We have the following outlets:
- five ring mains on B32s with 2.5 T+E
- three B16s feeding a single 2.5 T+E
- seven B6 1.5 T+E outlets
- one 6mm 3 core armoured cable

I was thinking of getting a "plain sides" CU so that I could drill my own entry holes and perhaps space them closer than the knockouts in a box that comes with knockouts, or staggered, so that I could maybe fit more glands than would be possible with a box with knockouts and using those knockouts.
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Can you not install the CU with a gap to the wall (on battens) and enter cables from the back?
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That’s a lot of circuits !


The house is quite long (about 60ft) so each floor's ring mains are split into two, one for each end of the house, plus there's a ring for the kitchen so 5 ring mains. Similar with the lights.

There's a 40A feed for a mini sub-main in the utility room (not yet installed but the feed cable is there) as there's a lot of stuff in there (3 freezers, fridges, washing machine, tumble drier, bread maker and other stuff).

Then there's a dedicated heating circuit (boiler + controls), one for the immersion plus a couple of circuits for the Annex and one for outdoor lights as well. It all adds up.
My other thought if not to use glands would be use these:

and maybe with the 25mm ones it might be possible to cut two separate slits so that I can pass two cables through one whilst maintaining IP4X. Obviously that won't be possible if both cables are passing through the same slit. I won't know until I try. I'm pretty sure I can do that with 32mm grommets but I don't know whether I can fit enough 32mm holes across the top of the CU.
Check the dimensions of the various cables and see if 2x2.5mm² is anywhere near another, say a 6mm²?

I'm fairly sure the rating won't be compromised once it's tightened.

EDIT: just re-read the thread and realised that's what you're debating.

Basically 3x2.5mm² T&E equates to 10mm² and 3x1.0mm² to 6mm² but 1.5mm² doesnt look like a match.
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Another way to do it is to use a big stuffing gland to take multiple cables and use filler pieces [like rolled up self amalgamating tape or intumastic acrylic] to fill any gaps.

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