Light switch wiring query

[nae_mair]

hi. I went to put a new light switch in my porch that controls the light in there and the front door security light and when I took the old switch off the wall I found what you can see on the picture attached. Can someone explain why it is wired up like this?

 

[ipf]

Without sounding silly can you explain this one a bit please if you can?

I've no intention of sounding silly, but think about it. If you're switching neutral instead of line what's the result......at the lampholder?

 

[JAWS]

I've no intention of sounding silly, but think about it. If you're switching neutral instead of line what's the result......at the lampholder?

Thanks.

I meant without me sounding silly not you.

 

[Octopus]

Yes it works. But not sure if I should wire up new switches the same?

You need this checked by a spark, as as it won’t take long, get them to check a few more.

How old is the property and / or have you had building work done or a rewrite ?

 

[StephenRowley]

I've no intention of sounding silly, but think about it. If you're switching neutral instead of line what's the result......at the lampholder?

When you go to change the bulb after turning power off at the light switch you'll still have a live supply there, so there is a risk of electric shock. Not that I would ever recommend sticking fingers into a light fitting regardless.

 

[ipf]

Without sounding silly can you explain this one a bit please if you can?

When you go to change the bulb after turning power off at the light switch you'll still have a live supply there, so there is a risk of electric shock. Not that I would ever recommend sticking fingers into a light fitting regardless.

Thank you.
I suggest you think about it, too......after reading the thread.

 

[nae_mair]

You need this checked by a spark, as as it won’t take long, get them to check a few more.

How old is the property and / or have you had building work done or a rewrite ?

Property quite old and is an ex council house.

 

[telectrix]

well spotted there. but..... has the switch been wired like that after the meter fitting monkey has reversed the polarity at the meter?????????

 

[Pete999]

If those are lives looped in the connector, it looks like you're switching neutrals. Get someone qualified to make sure.

Good spot Mate, was wondering what those 2 reds are doing in the connector block, so you are more than likely correct in your assumption.

 

[telectrix]

Just wondering if I should get a professional in to wire up new switch

think it's a good idea, and maybe an inspection of the installation is in order if as has been said, the polarity is incorrect, there could be a few more nasties lurking.

 

[ipf]

well spotted there. but..... has the switch been wired like that after the meter fitting monkey has reversed the polarity at the meter?????????

..a bit of good thinking, there........after all...
Two negatives = positive.
They may think n x n = live.

 

[JAWS]

Thank you.
I suggest you think about it, too......after reading the thread.

Is it the term they use for borrowed neutrals

 

[westward10]

Is it the term they use for borrowed neutrals

Borrowed neutrals is something different. This was common practice in the 70s to take the line supply from one level with the neutrals from another for two way lighting.

 

[Yozza19]

I think the black in the coman is joined to the 2 reds in conecter as it would of been tight getting 3 cables in the comman although you could of put a red each side and linked and he dint have any red cable left

 

[westward10]

I think the black in the coman is joined to the 2 reds in conecter as it would of been tight getting 3 cables in the comman although you could of put a red each side and linked and he dint have any red cable left

Yes this is possible but I think we need to side with caution in this instance.

 

[ipf]

I think the black in the coman is joined to the 2 reds in conecter as it would of been tight getting 3 cables in the comman although you could of put a red each side and linked and he dint have any red cable left

Bad thinking is that. What's with the two reds in the connector?......look closer, there are three.
Three t+e's, all accounted for.