Jump to content

question for the electricians


TomV
 Share

Recommended Posts

I've bought a new light fitting to replace one fo the standard pendant light fittings. The new light fitting has a connection block with only three terminals; neutral, live & earth. This particular light fitting has 3 cables coming to it, one of which is the switch, which needs to be wired on its own. Any thoughts how I can do this given I've only got 3 terminals?

Link to comment
Share on other sites

When you say 3 cables I can only assume it is

 

Cable from the Lighting Ring -> Cable to the Switch -> Cable from the Switch back to the light

 

This is actually taking your power from the ring through the switch AND Then to the light. You will more than likely find that there is anther junction box located in the void above the ceiling that is doing this shenanigans and in real terms you are only seeing the last bit pop out the ceiling. - You can then just connect the new light fitting to this - if you confirm it is being switched by the light switch - Just using the inlet that shows the cable coming from the switch in the diagram supplied.

 

But as above - if in any doubt please do get a spark in to carry out the work - doesn't need to be Part P or anything as you are replacing like for like.

 

Cheers

 

Steve

Link to comment
Share on other sites

Google " Wiring a light fitting UK" lots of guidance and diagrams. Whatever you do don't connect all the reds/browns to each other and all the blacks/blues to each other. :no: BANG seen it loads of times, one guy blew his fuse 5 times before getting help.

 

If you don't feel confident get a sparky

Link to comment
Share on other sites

Live in ,live to next fitting , live down to switch back this is in one block, from switch is S/L this is usually and black or blue wire with red or brown sleeve on it this is for your light fitting , neutrals together , earths together

ive only got 3 terminals in the new light fiting though

Link to comment
Share on other sites

What I suspect is that the old fitting was a standard ceiling rose which would have three term blocks (1 three way for neutrals, 1 three way for lives and 1 two way for switched live)

 

Have a look at the attached should help connect the new light fitting up (you will require some chocolate block)

 

If your not at all confident in doing this work please get a trician to assist.

 

 

Jeff

 

Wiring.pdf

Link to comment
Share on other sites

What I suspect is that the old fitting was a standard ceiling rose which would have three term blocks (1 three way for neutrals, 1 three way for lives and 1 two way for switched live)

 

Have a look at the attached should help connect the new light fitting up (you will require some chocolate block)

 

If your not at all confident in doing this work please get a trician to assist.

 

 

thanks for your reply. its a brand new house and hence all new light fittings. I just want to replace for a more modern fitting. The existing pendant has a number of differeent terminals. can i fit additonal connecor block into the new fitting?

Link to comment
Share on other sites

In this case I have connected the wires (as per the diagram) into the connector block and connected a separate wire to connect to the new fitting. I have then shoved the connector block up into the ceiling void and then connected the separate wire into the new fitting before I scured the new fitting to the ceiling. If there is room then there is no problem putting this new connector block inside the new unit

 

Jeff

Edited by jeffjjack
Link to comment
Share on other sites

sounds to me as thought your old lighting point is wired in what they call three plate.

1.if this is correct in your old fitting you should find 3 connection block in middle, the wires in there could be coloured red or brown, this is what they call the loop feed or supply.

 

2.then there is a two block terminal block with either red or brown ( in some cases this can be black if original installer was cutting back on buying proper twin red cable). i will tell you in a bit about that, also you should see the brown from the flex to lamp-holder going to same block.( this is know as the switched terminal)

 

3. the remaining terminal should have three terminals, in this should be a blue from the flex to your lamp holder and two blues or two blacks, this is the neutral terminal.

 

the reason for red/ brown. blue / black is that i don't know if your wiring is to the latest regs etc.

 

ok re if you have red and black conductors

 

4.power off. remove pendant cover remove black wire that is on its own with brown from flex. mark this black conductor so you don't get it mixed up with the other blacks ( on the neural side). this is the most common fault people make when changing fittings.

 

5. remove red wires from loop live terminal and remove blacks from neural terminal , remove earths from their terminal. base plate can now be removed.

 

6 locate fix fixing bracket of new fitting

 

7. the 3 reds from loop terminal connect together in a connector ( i use 15amp there's more room)

 

8.the 2 blacks go with the blue from flex of your new fitting

 

9. the single black ( you marked) goes with the brown from flex of your new fitting

 

10 most important.. if your new fitting is metal make sure you connect the earth wires to the green yellow of the flex and make sure you earth the metal fixing bracket of new light too.

 

the above is based on old colours, if you have new colours then replace red for brown, black for blue.

 

you should really do a polarity test, insulation resistance test, and loop impedance test the later checks how good your earthing is and if a fault should occur that the protective device will disconnect as quick as possible to prevent electrocution

 

you probably will not have such testers but using a hand held mains tester could be used to determine that you have an earth path.

 

to use this be careful with light fitting hanging so connections are accessible ( if fitting is heavy, secure it somehow so not hanging by wires).

turn power on

 

with probes of tester between live terminal ( which could be the loop live connections in the connector or the switched live when switch is on position going to brown of flex to light)and earth ( metal of fitting)

you should get 230-240v

 

there should be no voltage reading when probes are placed in neutral to earth. this is a very crude method for earth path its tells you there is an earth but does not tell you how good it is.

 

i hope i have explained it enough for you, i am sure others will post comments,, but it gives you some idea.

 

but like others have said if you want it done to the book and regs get the pro's in.

 

also i did not see any mention of where this new light is to be fitted, bathrooms, wet rooms etc are special locations seek more advise before you buy the new fitting and installation.

 

here is a link to the 3 plate (loop in) method of wiring using old colours

 

http://www.diynot.com/wiki/Electrics:Lighting-Circuit-layouts

 

just spotted your images as i posted this, you have new colour codes but following the above you cant go wrong.. hopefully lol

 

 

 

Edited by djgeoff
Link to comment
Share on other sites

sounds to me as thought your old lighting point is wired in what they call three plate.

1.if this is correct in your old fitting you should find 3 connection block in middle, the wires in there could be coloured red or brown, this is what they call the loop feed or supply.

 

2.then there is a two block terminal block with either red or brown ( in some cases this can be black if original installer was cutting back on buying proper twin red cable). i will tell you in a bit about that, also you should see the brown from the flex to lamp-holder going to same block.( this is know as the switched terminal)

 

3. the remaining terminal should have three terminals, in this should be a blue from the flex to your lamp holder and two blues or two blacks, this is the neutral terminal.

 

the reason for red/ brown. blue / black is that i don't know if your wiring is to the latest regs etc.

 

ok re if you have red and black conductors

 

4.power off. remove pendant cover remove black wire that is on its own with brown from flex. mark this black conductor so you don't get it mixed up with the other blacks ( on the neural side). this is the most common fault people make when changing fittings.

 

5. remove red wires from loop live terminal and remove blacks from neural terminal , remove earths from their terminal. base plate can now be removed.

 

6 locate fix fixing bracket of new fitting

 

7. the 3 reds from loop terminal connect together in a connector ( i use 15amp there's more room)

 

8.the 2 blacks go with the blue from flex of your new fitting

 

9. the single black ( you marked) goes with the brown from flex of your new fitting

 

10 most important.. if your new fitting is metal make sure you connect the earth wires to the green yellow of the flex and make sure you earth the metal fixing bracket of new light too.

 

the above is based on old colours, if you have new colours then replace red for brown, black for blue.

 

you should really do a polarity test, insulation resistance test, and loop impedance test the later checks how good your earthing is and if a fault should occur that the protective device will disconnect as quick as possible to prevent electrocution

 

you probably will not have such testers but using a hand held mains tester could be used to determine that you have an earth path.

 

to use this be careful with light fitting hanging so connections are accessible ( if fitting is heavy, secure it somehow so not hanging by wires).

turn power on

 

with probes of tester between live terminal ( which could be the loop live connections in the connector or the switched live when switch is on position going to brown of flex to light)and earth ( metal of fitting)

you should get 230-240v

 

there should be no voltage reading when probes are placed in neutral to earth. this is a very crude method for earth path its tells you there is an earth but does not tell you how good it is.

 

i hope i have explained it enough for you, i am sure others will post comments,, but it gives you some idea.

 

but like others have said if you want it done to the book and regs get the pro's in.

 

also i did not see any mention of where this new light is to be fitted, bathrooms, wet rooms etc are special locations seek more advise before you buy the new fitting and installation.

 

here is a link to the 3 plate (loop in) method of wiring using old colours

 

just spotted your images as i posted this, you have new colour codes but following the above you cant go wrong.. hopefully lol

 

 

 

thank you for your comments, sounds like I need an additional connector block to put in the new light fitting for the switch live. as you say neutrals togther, lives together and earths together. i've already fitted one of these (slightly simpler as there wasnt three incoming cables) i'll give it a go on saturday. thanks for your help

Link to comment
Share on other sites

 

thank you for your comments, sounds like I need an additional connector block to put in the new light fitting for the switch live. as you say neutrals togther, lives together and earths together. i've already fitted one of these (slightly simpler as there wasnt three incoming cables) i'll give it a go on saturday. thanks for your help

no not the switched live, its the looped the three browns in the middle of old fitting

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
 Share

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...