LV Wiring through inter tenancy walls/floors

[downtoearth]

Hi All,

Not sure if this is the right sub-forum so feel free to move if required - would possibly fall under a 'general' question?

I'm currently working on a property which has 2 separately metered tenancies, 1 above (Level 1) and 1 below (Ground). I need to run a new circuit for L1 and the easiest way to do this would be to drill down into ground floor tenancy, along their ceiling and back up into L1 tenancy. I've had a look and haven't had much luck but does anyone know any rules/regulations surrounding this idea?. My concern is if the below level was thought to be isolated when you turn off the main switch, you would still have live cable(s) fed from the above tenancy. Whether or not conduit with identification would be sufficient for this I'm unsure? Feel free to list relevant standards/acts so I can have a read through.

Cheers

[AlecK]

There is no prohibition on wiring of one installation being in same structure as another installation.
In fact having multiple installations in same structure is not uncommon.
Multiple tenancies each being part of one larger installation, all on same structure is even more common.

3.9.8.2 covers this (amended for 2018 edition)
As long as wiring for different installations / tenancies is not in same enclosed duct or multicore cable; it's worker beware.
Wiring rules cover safety of installations.
Safe work practice is "4836" (and ESR 100 says we hsve to follow it.
Making assumptions about cables being dead, without testing, is a BOG no-no.