Changing light fixture with red/black UK wiring using only black wires

Question

I am planning to change a ceiling light fixture in my 1980s-built home in the UK.

I had a look at the box and was surprised to see 3 red wires nutted (?) together and 3 black wires feeding the light. And a healthy amount of tape.

Even though the wires are red and black, the fact that the 3 red wires sit unused does not seem to match any UK wiring scheme of any era, but hopefully I am wrong!

The two beige cables go to the light box hanging below.

Can someone tell me what's what? Note again this is in the UK. I don't know how old the wiring is but the house was built in the 1980s.

Answer 1

Standard UK loop in wiring.

The 3 reds joined together will be live in, live out (to the next light) and live down to the switch.

The 2 blacks joined together willl be neutral in, neutral out.*

The black on its own should be sleeved brown (was sleeved red) for switched live.*

The new light connects to * and * (and earth, if it's not doiuble insulated).

from

https://www.practicaldiy.com/electrics/lighting-wiring/light-wiring-loop.php

Answer 2

Your new fixture connects just like the old one. Don’t get upset that someone did not follow the proper color code as your code has changed over the years. Connect your new fixture to the same 2 wires that the existing fixture is connected to. Those brown wires are high temp fixture wire and usually connect to a fixture. I would go back to there splices but if your new terminals don’t have enough spots to land the wires just cut the brown and use those in your terminals. (I could not tell if there were multiple wires and the kind of tape) if only 1 wire eliminate the mess.