Rose circuit bedroom wiring mayhem, 3 blacks dosnt work!!!

[Ale170]

After purchace of three debanhams lights and sucessfull fitting of 2 the third has caused me some unrest due to an ensuite bathroom within the circuit.
1) Presented with three reds and three blacks i wired the three reds togther. Wire 2 blacks into a sucessfull bedroom switch leaving one exposed black, if i use the bathroom light the box blows and if i connect the 2 blacks short circuited fuse box again occurs
2) one pair is live. The other 2 pairs are not. I am aware of the alternate wiring utilizing 2 reds 1 black, but with one live pair i cannot identify the two other pairs
Please help because the light was 54 pounds and the callout charge is 50.
Thanks
Ale170

p0

 

[Leesparkykent]

you need to identify the switch wire. what test equipment do you have?

 

[Ale170]

Ive got the old light fitting, if its live the light works, cheap but effective

 

[westward10]

Not sure what your last post means.

 

[Leesparkykent]

Ive got the old light fitting, if its live the light works, cheap but effective

That won’t help you identify the switch wire.

 

[Dan]

I apologise for @Pete999 being super unhelpful. Again.

 

[James]

Unfortunately in this case, I think that getting some professional assistance is your best option.

if the cables had been photographed in place when connected to the original fitting and marked up so they could be identified, it would have been possible to describe to you the function of each one.

when faced with 3 reds, 3 blacks and no other info to go on, it is an impossible task to advise with any degree of certainty.

electricity is not something to be messed with by using trial and error,

if nothing else, you should at least make those cables safe by putting them into 6 separate terminals and properly joining the 3 x earth cables together.

 

[westward10]

From a distance it is impossible to say which black is the switch line return. Unless you have some kind of continuity tester and know how to safely use it you need professional help.

 

[Ale170]

Well it has taken several hours of my time already, investing in an electrition is an option i will likley undertake, i do have wallpaper to hang to distract myself from the cost of leaping without looking. Im still open to suggestions, ive got big nitrile gauntlets, i wont be electricuted.

 

[Spoon]

Just to add to the above, how may earth wires do you have? I can't see 3 in the pic.

Well it has taken several hours of my time already, investing in an electrition is an option i will likley undertake, i do have wallpaper to hang to distract myself from the cost of leaping without looking. Im still open to suggestions, ive got big nitrile gauntlets, i wont be electricuted.

But you have no continuity tester, so its hard to see what cable does what.

 

[Ale170]

This is my assumed wiring.
Cable A is live,
Cable B and C are not live. How do you identify B and C correctly.
(5 marks)

 

[Spoon]

This is my assumed wiring.
Cable A is live,
Cable B and C are not live. How do you identify A and B correctly.
(5 marks)

View attachment 52512

With test equipment...
Yaaay I get 5 marks...

 

[Barry123]

^ beat me to it

 

[shaun1]

Electrocution is not the only risk here. One pair (a red and a black) go to the switch. As you cant identify these, every time you connect them to Line and Neutral you sre basically making a short circuit when you turn on the switch. Given the likely resistance of your average lighting circuit, you are probably getting a current flow of at least 200A every time you test it (often refered to as a bang test for obvious reasons).

That large current flow will start to cause stress and damage to the wiring and MCBs if you keep repeating it. So I would strongly recomend that you do not energise the circuit again until you are certain you have it wired correctly.

 

[James]

turn off power, connect continuity tester between red and black on suspect cable, if the beep goes on and off when you change the switch position, you have found cable C.

I get 5 marks too.

edit, @shaun1
this is correct, by now, you may already have welded the contacts closed on the switch or damaged them to the point where the switch may get hot or fail to work.

be honest with the spark that comes to fix it, if you decide to take that advice.
they may well change the switch as well for a few £ just in case it is damaged.