DIY Doctor UK DIY Forums

I TRIED TO WIRE UP A CEILING FAN BUT AM HAVING MAJOR HEAD ACHE I HAVE 2 GREY WIRES WITH A RED AND A BLACK IN EACH . BOTH BLACKS ARE LIVE AND SO IS ONE OF THE REDS. WHICH DO I WIRE TO THE FANS LIVE / NEUTRAL / EARTH. HOPE SOMEONE CAN HELP . ALSO NO MATTER WHICH WAY I WIRE IT THE LIGHT SWITCH IS CONSTANTLY LIVE. HAD IT WIRED SOMETIME AGO LEFT THE SWITCH ON AND IT COMES ON ON ITS OWN AFTER A COUPLE OF HOURS / DAYS. COULD THE FAN BE KNACKERED.

Hi, something worrying here!! one red & two blks live... No way!
If you are testing with a ruddy neon screw driver THROW IT AWAY they are totally misleading!!!!
you make no mention of earths, are there any? if so sleeve and connect to earth term.
I presume you are at ceiling light and if so the 2 reds would be in a spare connector the blk from one cable would be in Neutral term of light and the other blk is sw/live back to L of light (it should be marked with red tape/sleeving), your fan L&N connect to these 2 also, if still unsure get professional help please,regards SPARX

Hi Sparx,

Probably a naive question - what's the problem with neon mains-testing screwdrivers?!

Hi Tortoise,
because they have no return reference point the tester will see any floating voltage around the system which may only be induced voltage from an adjacent core.
Same applies to a digital multimeter, hold the probes in the air near a powered circuit and see a reading!
Neon lights , maybe pick up, maybe neutral with broken connection, maybe live! who knows?
Using multi neon two connection type tester totally different as they need ref. Neutral/Earth to show a live, not fool proof but much better.
The latter type being the only ones acceptable for proving isolation for Electricity at Work regs.
I will not use a neon test driver myself & i've been leckie since 1960's and seen experienced sparkies chase their tails using one to fault find!
So don't recommend them to anyone posting on here as I believe they are dangerously misleadeing to the unwary,
regards SPARX