On 29/04/2020 09:54, wrote:
How to get 4 cables into this CU?

Metal CU has clearances of:
top 4"
bottom 4"
right: 0
left: plenty, but the tails run up there.

A christmas-tree cone bit is at least 2" long, leaving little space for a drill for top or bottom.
Right is possible by drilling through what it's up against, but the result would look lousy.
Left there's enough space in theory, but a lot of hand held drilling with a large bit very close to tails? Not loving that idea.
Looked at cutting into the front edge rather than using round entry glands, but not seeing fireproof grommet strip anywhere.

Suggestions welcome!

Aren't there any knock-outs to, errr, knock-out?
If not, you could get a nibbler into a 4" gap and then improvise grommet
strip from anything suitable (saw blade protector, slit sleeving, T&E
outer ...) and then use high-temp silicone to form a seal.
I have a hand nibbler and also one that goes onto a drill, for this job
I'd use the latter. Mine is one of these:
https://www.ebay.co.uk/itm/Falcon-Ni...-/250816902636
but bought 10-15 years ago and much used for sheet metal work.