Taking Power From Socket For Light Switch

[DeludedAussie]

I have read the wiring diagrams on this website but i am confused. I want to do something very simple.

I want to take power from a socket and put this into a light switch

What I thought would work is:

1) Cable from socket with brown and brown in choc box and blue and blue in choc box to light switch

2) Brown in com and blue in l1

3) From same light switch I have a cable with brown connecting to brown and with blue to blue

So in short all the colors match when connected

The problem is this causes the RCD to trip and I cannot explain why

Can someone lend a hand on what I am doing wrong please

I ve attached pictures which hopefully shows what I am doing - The brown and red from socket is being joined together

 

[Jackrae]

"In short" yes it well and truly is. If I interpret your description correctly your light switch places a direct short across your system when you turn the switch ON. The result is a massive overload which trips the "RCB" don't you mean MCB. Apart from that you cannot run a lighting circuit from a 30A ring main, you cannot use flexible cable buried in a wall and the flexible cable you have used in incapable of passing the current that the socket power circuit is designed to supply.

 

[EFLImpudence]

Plus -

The socket has no back-box or pattress.
It doesn't look new. How has it been fixed to the wall?

The socket has only one cable indicating it is a spur so no further wiring should be taken from it without fusing-down before the socket.
It could be the last on a radial but that would be unlikely.


You say you have read the diagrams on the site but you will not have seen a switch wired as you have.
Draw a diagram of what you have done and think what will happen when you 'close' the switch and what you need to happen for the light to work.

 

[DeludedAussie]

Thank you very much for your help

I have tried to take a cable direct from the socket (bypassing the switch) straight to a light and it does work. The light comes on and there is power so I do not think it is a radial.

The problem occurs when I try to involve the light switch and you are right that the mcb trips.

Given that the light works when taking power from socket directly it must be because of how I am wiring the light switch.

I assume that I need one way switching so my brown live is coming from the power socket to the com port and my blue neutral is coming from the power socket to L1 on the switch. From my light switch I have another cable which will hopefully be the cable I use for the light.

The switch is there just to allow me to switch on and off the light.

Am I correct in thinking that the colors need to match at the light switch because ths is what I have done.

Any help appreciated. I tried to draw a diagram but I had difficulty. Could you explain how the cable (from power socket) should be fed into light switch and how cable out of light switch (for the light) should be wired

I am trying to learn electrics by doing small things in my house

EDIT: Should I have two additional cables going into the socket to make a ring (making a total of three)? Your help mostly appreciated

 

[EFLImpudence]

Ignore the cable marked 'OUT'.

You must understand before continuing.

If the socket circuit is controlled by a 30A fuse or 32A mcb then
you will still need a 13A fused connector before the socket and a 3A fused connector after the socket before the light wiring.

 

[DeludedAussie]

Ignore the cable marked 'OUT'.

You must understand before continuing.

If the socket circuit is controlled by a 30A fuse or 32A mcb then
you will still need a 13A fused connector before the socket and a 3A fused connector after the socket before the light wiring.

thanks somuch

the switch has a 10amp fuse already - is that enough?

 

[ban-all-sheds]

the switch has a 10amp fuse already - is that enough?

Your switch has no fuse.

PLEASE stop all your fiddling with things you don't understand until you've spent some time learning and you do understand. Right now you're an electrocution and/or fire waiting to happen.

• http://www.google.co.uk/search?q=electrical+circuits+101
  
  
• http://kevinboone.net/electricity.html
  
  
• http://web.archive.org/web/20080213151445/http://www.kevinboone.com/domesticinstallations.html
  
  
• //www.diynot.com/wiki/electrics:books
  
  
• //www.diynot.com/wiki/electrics
  
  

 

[ericmark]

Instead of light switch use a switched fuse connection unit this will do two things.

1 - It will give you both line and neutral connections on the switch no need for chock blocks for neutral.
2 - You can fuse down to 3 amp.

Maximum allowed for lighting is 16A and most ring circuits are 32A so needs fusing down. Many light fittings only rated at 5A so likely a 3A fuse is required.

As you can see look like a switch but have fuse and behind there is both line and neutral connections.

 

[DeludedAussie]

Ignore the cable marked 'OUT'.

You must understand before continuing.

If the socket circuit is controlled by a 30A fuse or 32A mcb then
you will still need a 13A fused connector before the socket and a 3A fused connector after the socket before the light wiring.

thanks somuch

the switch has a 10amp fuse already - is that enough?

I tried this exact approach (which is simple) and the RCD tripped.

I have two blues together and one brown in Com and one brown in L1 and the MCB tripped.

Any ideas why?

 

[Aragorn84]

You put both of the blues AND the brown in com?

If so, Thats why.

 

[Scoby_Beasley]

Thanks to EFL It should look exactly like:

Untitled

• Scoby_Beasley
• 19 Feb 2013
• 1

 

[EFLImpudence]

And Flameport.

 

[Scoby_Beasley]

And Flameport.

I was thinking of removing the name as well.

 

[Monkeh]

you cannot use flexible cable buried in a wall

How's that?

 

[DeludedAussie]

You put both of the blues AND the brown in com?

If so, Thats why.

hi i put one brown in com one brown in l1 and two blues together in l2