light switch replacement - keeps tripping electric

bjorn_toby_wilde

Re. one side only having three wires it could be that’s because one side is master and one side is slave.

Maybe the other switch mentioned is also a 2 gang 2 way, wired exactly the same way but with roles reversed.

https://wiki.diyfaq.org.uk/index.php/2_Way_Switching

Hope that makes sense. Half way down the page there’s a diagram showing wiring for controlling two lights from both switches.

grumpy_codger

Re. one side only having three wires it could be that’s because one side is master and one side is slave.

Also, the light(s) can be connected to a junction box in the ceiling, not necessarily to a switch

Section62

https://forums.moneysavingexpert.com/discussion/comment/81943948#Comment_81943948

Trouble is, if that’s the original wiring and it was working like that then why isn’t it now?

Good question - which is why the OP probably needs to call an electrician rather than taking guesses from friendly folk on the internet. We don't know that the red sheathed wires are permanent lives, and it isn't beyond possible the blue and black in the near 'L2' are neutrals, despite the red sleeves. We have zero knowledge of the competence of the original installer and what they were thinking.

To solve this one safely means using test equipment to figure out exactly what is going on.

A professional electrician would also be able to sort out the (lack of) earthing.

wakkaday

It was the main consumer unit it would keep switching off the turning off wouldn't allow me to switch it on

It looks like I did the wiring wrong from the looks of it

The old switch has

com / L2 / L1 (TOP OF switch layout )

L2 / L1 / com (BOTTOM of SWITCH layout )

The new switch has the coms in the same place but it's as follows

COM1 / L22 / L21. (TOP OF SWITCH)

L12 / L11 / COM 2 (BOTTOM OF SWITCH )

So L2 corresponds L12 from what is being mentioned and L1 = L11

And the bottom L2 / L1 on the old switch correspond too

L2 = L22 on the new switch

L1 = L21 on the new switch

Will let the kids eat breakfast and power off the electric before starting

bjorn_toby_wilde

https://forums.moneysavingexpert.com/discussion/comment/81944019#Comment_81944019

That’s what I would do too. Get it properly tested.

Section62

https://forums.moneysavingexpert.com/discussion/comment/81944066#Comment_81944066

I don't think that is your problem. The labeling of the terminals is different, but the functionality should be the same.

I'd strongly suggest you call in an electrician. As well as the risk of you electrocuting yourself (or your family), incorrect wiring poses a risk of fire and/or doing further damage to the electrical installation.

At the moment you have a relatively straightforward situation for someone with the right knowledge and test equipment to fix. If you damage a cable, or equipment in the consumer unit, the final bill could be considerably higher.

In the nicest possible way, if you can't identify what exactly is tripping then you lack the 'competence'* to carry out this work. (*competence in the technical sense of who should and shouldn't carry out work on electrical installations)

WIAWSNB

https://forums.moneysavingexpert.com/discussion/6661960/light-switch-replacement-keeps-tripping-electric

Do you have a wider shot of this wiring, to show to which cable each coloured wire goes to?

WIAWSNB

It would appear that the two light switches are both BG make, and have the same terminal layout despite being different models.

In which case, the issue is most likely down to a mix-up between similarly-coloured wires, such as the reds - of which there are three - the yellow/reds (two) or the blue/reds (two).

But, without a wider pic to show where each of these wires are coming from, I think you'll struggle. A sparky should sort it in good order, tho', but you'll have to contend with a lot of eye-rolling.

Section62

https://forums.moneysavingexpert.com/discussion/comment/81944245#Comment_81944245

But, without a wider pic to show where each of these wires are coming from,

I agree that the lack of a picture showing the cables makes it harder to figure out what is wrong, but there is a danger in making assumptions about what each wire does based only on which cable it comes from.

Without knowing what is on the other end of each cable/wire, it would just be a guess.

Heedtheadvice

Crikey I am glad you are posting Section62 and giving proper and good advice.

Saves me posting and complaining about well intentioned posters making guesses and assumptions where safety is involved.

A electrician will cost but should ensure a safe fix ....and the OP should value his kids lives and his, as a parent.

As sensibly posted too, not being able to answer the simple question of what exactly is tripping ( be it a main breaker or circuit mcb/rcb/rcbo) strongly indicates lack of competence to do the job safely, tested and to current regulations.

With help on forums such as this you might get correct switching functionality but not necessarily safe. If that socket has not be properly installed originally or at some time and has a missing earth suggests the test of the property ought to be checked!!