Main Circuit breaker tripped

[ipbr21054]

As per title main circuit breaker tripped.
I reset it at main consumer unit but same again.
I switched off each individual breaker if that’s what you call it.
I then switched on each 1 at a time until it tripped again.

I have now electric on apart from the lighting in my spare room so this is the issue.
The breaker would trip even without any lights on.
I’ve removed the faceplate on one light switch & see 3 black wire twisted together & then placed into a wire block, the type where the screw goes down through the top, choc box ?
The wire where twisted seems to have some rust on it.
Removing the choc box I’ve now cleaned it up & replaced with a new choc box.

I’ve noticed the box that all the wires re in in plastic & then screwed to a wooden batten.
The earth wire is located in the little brass block, I assume it’s not doing anything as it’s all plastic & so just located there so all is neat.

My question is I wish to switch the breaker back on for the lights but with this switched removed so I can rule it out.

In the back of this switch I see 3 red wires.

1 red wire is located in the top of this block.
The other 2 red wires are both located in the same hole at the bottom of the block

Do I just remove the red wires from the block & make sure the 2 at the bottom are making a connection with each other or is that the same as just removing the single top wire & move to one side.

Thanks.

 

[trojanhawrs]

It's unlikely the switch will be at fault. The circuit breaker that's tripping is almost certainly a RCD, if it has a test button on it then thats what it is.
It senses current leaking to earth which is often caused by cable damage and water. The 2 wires in the bottom are likely the supply and the other the switch to the light. You could try separating and putting them each in a choc block while you test,

 

[ipbr21054]

There is no button. It’s just a on / off item.
When you say separating do you mean remove light switch.
1 red wire in 1 choc bloc block & then the other 2 in there own choc block.
Please advise thanks.

Also advise what I mentioned about earth wire.

 

[flameport]

There is no button. It’s just a on / off item.

Please add a photo of that and the rest of the consumer unit.

 

[trojanhawrs]

Leave the 1 red wire in the switch, take the 2 out and wire them into separate choc blocks.

 

[ipbr21054]

As requested thanks.

 

[trojanhawrs]

You're saying that red main switch tripped?

 

[Jurassicspark]

So the breaker which is in the off position right now is tripping?

Disconnect the two joint red wires at the switch and try seeing if the MCB still trips.

 

[ipbr21054]

This consumer unit is an addition to my main in in the house.
All electric now on when this light breaker is off. Previously when I switched it back on main would trip again.

 

[trojanhawrs]

Right, but I'm assuming the breaker that tripped at your main consumer unit has a test button on it, no?

 

[ipbr21054]

With regards post 8 yes this one in the off position makes it trip. This is why I have left it in the off position.
In the morning when it’s light I will remove the 2 red wires from the switch & separate them & advise what happens.

 

[ipbr21054]

Regarding post 10 here is the main consumer unit.
The last one on the right was I believe in the middle position. I’m sure I moved it down then all the way up to the position you see now.
I didn’t touch anything else.

 

[trojanhawrs]

As I expected, try as above and report back.

 

[ipbr21054]

Try as above.
You mean separate the 2 red wires

 

[trojanhawrs]

Yep