Upgraded light pendant after decorating. Now doesn't function properly

[user 36756]

Hi

I thought this would be very basic, I have upgraded many light pendants in the past without fail.

If someone could help, that'll be great. Otherwise I'll have to call a local electrician round.

The basics is -
- The existing light fitting had a connection box (two black wires, two red and one earth)
- Since my new light pendant had an existing connection box, I removed the old one and wired the wires in
- I made a mistake initially because the original connection box had the two black wires separate, so I wired the new light pendant in with the two reds connecting to the brown, and the two blacks connecting to the blue. (old wiring in my house)
- This tripped the fuse box on light circuit and I realised my mistake
- I then put the two black wires separate, like the original connection box, but had to guess which black wire to connect to
- Having tried both black wires, when the first is connected it stays on and the switch at the wall does nothing. When the other black wire connected, the switch at wall does nothing and it never turns on.

Update: Having tested the light switch at the wall with a multimeter, the switch no longer functions as there's continuity even in the 'off' state. This is the one I suspected was faulty after having connected it wrong because it didn't make much of a 'click'.
However, the one I switched over from another room does work, but I still have the same issue where one black wire makes light always on, and the other black wire always off.

I can't get my head around it, unless I've damaged something with the initial mistake.

 

[monkey5]

The 2 reds go to the middle block then 1 black to the blue from flex and the other to brown from flex, ideally you need to know which is SL and which is N but if its a BC lamp it won't be the end of the world, if its an ES lamp then it does matter, do you have any test equipment at all?

 

[monkey5]

If that doest work you may have fried the switch with the original setup but let us know how you get on with what I've said above

 

[user 36756]

The 2 reds go to the middle block then 1 black to the blue from flex and the other to brown from flex, ideally you need to know which is SL and which is N but if its a BC lamp it won't be the end of the world, if its an ES lamp then it does matter, do you have any test equipment at all?

Thanks. It is a BC lamp.

I have a multimeter but I'm not comfortable using it on live wires. I am comfortable using it with the fuse box off.

 

[monkey5]

You should be able to work out which is SL with power off. With power off, and MM set to ohms, put one probe on the red and one on one of the blacks at a time and operated the switch, one of them should give you a very low reading when switch is on. This one is the SL and goes to the brown

 

[user 36756]

If that doest work you may have fried the switch with the original setup but let us know how you get on with what I've said above

As in my edit, the original wall switch doesn't work anymore. However I have another one that does work.

 

[monkey5]

Change the switch for the one that does work and then do the test with the MM

 

[user 36756]

Thanks a lot, life saver. Works fine now.

 

[monkey5]

No worries