bedroom light

[purple_pill67]

hi,
just found this forum via google....hopefully someone can help me out.

we've just got a chandelier from dunelm....this has the live/neutral/earth wires from it,it comes with one of those plastic junction boxes to connect to the house supply.
when i took the old light down theres 2 sets of live/neutral/earth wires from the ceiling......i thought pairing these up going into the likewise wires for the chandelier would be ok......
it blew the fuse just before it did the bulbs were lit up even tho the switch on the wall was in the off position.
all the pics i can find online are for 3 sets of wires from the ceiling,any ideas where im going wrong??

 

[ltheb]

Are the wires red & black or brown and blue?

 

[JohnD]

2 sets of live/neutral/earth wires from the ceiling......i thought pairing these up going into the likewise wires for the chandelier would be ok......
it blew the fuse

I think that, if you have two cables, each containing a Red, a Black and an Earth wire, then one of them will be the circuit supply, and the other will be the switch.

You must NOT connect these two cables to each other.

If you have a multimeter we can help you identify which is which.

If not, turn off the power, connect one of the cables to the lamp and park the other. If the lamp is now permanently on, that is the supply cable. Mark it with tape or a felt pen. If not, try the other.

If you have a dimmer switch it is probably **cked now. Get yourself an ordinary on/off light switch.

Have a look at FAQs and Wiki at the top of this forum.

Then come back and tell us how you got on.

 

[ltheb]

Sorry, three questions:
1) colour of wires
2) do you have mains tester scredriver or multimeter?
30 do you have some plastic insulated connector blocks?

 

[MANDATE]

You have caused a short by connecting the two blacks together.
First you need to identify the two cables. One is the switch cable and the other is from the CU or another light. The two reds should be connected but not the two blacks. The light should be between the two blacks.
These are not two neutrals, one is neutral and one is a switched live. It should have a red sleeve on each end to indicate that.
Look at it like this! electric travels along red in CU cable, it connects to red in SW cable and down to SW. From SW the black (sleeved red) goes to light(which is the load) From light it connects to neutral in CU cable and completes the circuit

 

[purple_pill67]

thanks for the replies!
to answer a few Qs before bed:

from the ceiling both sets are black+red+bare earth.
the light has clear with blue thread,clear with brown thread and clear,they also had sticky tags on too but i had to trim them down as their was too much spare wire.

i dont have a multimeter,where would be the cheapest to get one from tomorrow? what do i check to find out which set of wires is which??

its just a plain switch on the wall,no dimmer or anything like that.

the light comes with 2 plastic insulated connector block,one with 3 slots and one with just 1. the single one is incase you have a "loop" the instructions say.

ill have a look in the "wiki" + FAQs tomorrow if i get chance.

 

[Spark123]

See if you can follow this: http://wiki.diynot.com/electrics:lighting:problems:blackswlive
Any problems, just shout.

 

[Steve]

There is one VERY helpful diagram in The WIKI that covers this very scenario.

You will need that 4th terminal.

the 2 reds will park here.

the 2 blacks will then go to the L (brn) and N (blue) terminals. The black from the switch should go to the L, but most fittings aren't fussy these days.

Multimeter from maplins. They have a good range.

 

[JohnD]

...or if you want to pick up a meter in the morning, most DIY sheds or hardware stores will have them. A simple £8 yellow one will do.

 

[purple_pill67]

cheers,we dont have a maplins in gloucester and im not gonna try fighting are way to cheltenham today! ill walk in to town and see if i can find owt,if not a trip to b+q (again).

thanks for that link,i guess i can use the single block for the supply+switch RED

 

[purple_pill67]

got a multimeter in wilkos,£8....hope it has the right settings on it....didnt fancy £25 from argos!

which wires+readings do i need to figure out which is the supply and which is the switch?

 

[JohnD]

1) Turn off the power

2) Put the cable cores into a connector block (one wire to each terminal, not connected to each other, so you can test then safely.

3) Set the meter to "AC Volts" with a range that includes 240 volts

4) Put the power back on

5) Taking care not to touch anything with your fingers, touch the probes to the red and the black cores of one cable, then to the other. The one that indicates (about) 235 volts is the supply cable. The one that has no voltage will be the switch. If none of them indicate power, you may have connected the meter's probes wrongly, or set it wrongly. Have another look at the instructions.

6) Turn the power back off. Retest the cables to verify that all of them are now dead.

7) Using a biro or fibre-tip pen, write "supply" on the sheath of the cable that you identified as supply.

6) Set the meter to "continuity" or low range of "ohms" or "resistance" (depending on your meter). You may need to replug the probes. Touch the two probes together, and the meter should indicate continuity or a very low resistance. It may bleep. This demonstrates that the meter is working.

7) with the power still off, touch the probes to the cores of the other cable. Note the meter reading. Turn the light switch "on" and touch the probes to the same cores. Note the reading. The meter reading will be very different. This indicates that you have found the switch cable. Write "switch" on the cable sheath. Put a tag of red tape on the black core of this cable.

You have now identified the Supply and the Switch cable and can proceed as shown in the Wiki.

8 ) Write 100 times "when I disconnect a light fitting I must note the position of all the old wires"

 

[purple_pill67]

cheers,will do that when the missus is home!!

8 ) Write 100 times "when I disconnect a light fitting I must note the position of all the old wires"
haha!i will next time!!