hallway and landing wiring problem

I have just changed a light fitting and have messed up the original wiring.

In the circuit there is a double switch at the bottom of the stairs that controls the hall way light and the landing light and upstairs a single switch for the landing light.

I have 4 twin and earth cables coming to the hall way light that I replaced and am totally confused how to wire them correctly. Everything was fine and i did copy down where they all went but obviously got it wrong.

I have a multi meter but do not know where to start. Any help on solving this problem would be most appreciated.

If you require any more info please let me know and thanks in advance for any replys.

Mark...

(Yawn) There's a diagram on this in the FAQ

One of the pairs of wires will be from the switch. If it was installed corectly the black (or blue) wire from the switch will have a red (or brown) sleeve on it.
that wire goes to the live side of your light fitting.
All the blacks/blues go to the neutral side of your light fitting
All the reds/browns should be connected together.

thank you for the reply

I havent managed to get the landing light working but the hall way light is.

None of the wires are marked just 4 sets of twin and earth going to the hall way light. I have found out which wire is the supply (live). Any suggestions on how to fix or work out what wires should go where would be hellpfull.

Thanks once again for your time.

Mark...

You are looking at the ceiling rose where you have found 4 T&E cables?

Have you got a multimeter? If not, pop up to the High Street or DIY shed with £10 and get one. It will make a huge difference.

While you are there, buy some white and some red vinyl tape and a permanent marking pen (biro-sized) and a strip of plastic "choc block" 6a connectors, which you will use to park the wires in while testing.

You will also need a small and a medium electrician's screwdriver and a little green and yellow sheathing. If they sell red sheathing, buy the shortest possible length of that too (assuming your T&E is red and black. If it is Brown and Blue, get Brown tape/sheathing).

If the wires are dirty, a little meths will be handy to clean the PVC sheathing and insulation (I will be asking you to write on them with your marker pen as we go along).

Thank you for your reply.

I have the tape etc and am ready to have a go. I have a multi meter as well.


All wires are red/black/earth

Regards


Mark....

Sorry have been away

First, turn off the power and use your plastic connector strip and your small insulated screwdriver to put each core into a separate terminal. This is so you can poke them with the test probes without (much) fear of electrocution or letting then touch each other, or getting them mixed up while you are testing. For the moment, write "1" "2" "3" "4" on the cable sheaths with your marker pen (or on a bit of the white tape if the sheaths are too dark) and draw the layout of cables and cores on a large piece of paper.

You can put all the earth Wires into a singe terminal (if they will fit). if any of them ae not adequately sheathed, slip your G&Y sheathing over them except for enough to go into the terminal.

I think you said you have already identified the Supply cable. This should be the only one that is live. So you can mark this cable sheath "Supply In" and put tape over the terminals to avoid touching it again accidentally.

Set the meter to "AC Volts" in a range that includes 230v and check that the meter and probes are working by touching the probes to the terminals of the known supply cable.

Then,

Check between all the cores to make sure there is nothing else live - i.e. core 1 to 2, 3, 4, 5, 6; then core 2 to 1, 3, 4, 5 6; then core 3 to 1, 2, 4, 5, 6 etc. None of then should be live, only the supply cable. If you detect voltage, mark it on your sketch.

Next we will look for the Light switch Cable.

Make sure the power is off (just in case.

Set your meter to "Continuity" or "Low Ohms" and touch the probes together to check that they show when contact is made.

Now check for each cable (except the supply one) between the red and the black cores of that cable. Note if any show continuity or a very low resistance (it is an advantage to take out all the light bulbs in the house, but this is not essential if it is difficult).

Now operate the light switch and do it again.

You will (should) find that the cores in one on the cables had continuity when the switch was "on" and not when the switch was "of". You may also find that you had continuity on one or more of the other cables (possibly with a higher resistance) but it was unaffected by the switch.

Now, mark that cable sheath "Switch" and update your sketch. Put a stub of red sheathing (or red tape) over the Black core of the switch cable and mark it as "Switched Live"

Next put the kettle on and make a pot of tea while I have a rest and write the next chapter!

Right!

There will now be one or more cables, which are not the supply, and are not the switch.

These will be carrying the supply to the next lamps in the house (probably the next room. You might even be able to guess where they are going from the direction they go.

Mark these "Supply out" with your tape and on your sketch.

Now:

You can connect the Red "Supply In" to the red "Supply Out" cores; and the Black "Supply In" to the Black "Supply Out" cores".

Note that I have not yet told you to do anything with the switch cores, so they will both be on their own in separate terminals. This is VERY IMPORTANT.

Having done this, you can check for loose wires, and turn the supply back on. You should find that all the other lamps in the house work when you switch them on, and off when you switch them off.

Pat yourself on the back and have another mug of tea.

If the lighting circuit fuse blows, or MCB trips,either at once, or when you operate the light switch in the room you are working in, ask you wife to spank you for carelessness and check what you have done.

You have now identified the Supply In, Supply Out, and switch cables. You have sheathed and gathered together all the earths. You are now ready to make the lights work in the room where you are working.

Put the RED core from the Switch cable into the same terminal as all the other red cores. Put the Black (but with a red marker on it) core from the Switch cable into a terminal ALL ON ITS OWN WITH NOTHING else. this is very important.

You light fitting, pendant chandelier or whatever is likely to have three terminals. these will be earth (might be marked with "E" or an upside-down christmas tree); Live and Neutral. Or in colours Gree/Yellow; Red and Black. or in colours G/Y, Brown and Blue.

Identify these terminals.

You may need three extra bit of insulated coloured wire next, if the lamp fitting is not already fitted with them in the appropriate terminals of the lamp fitting.

Connect the G&Y to the terminal with all the other G&Ys in it.

Connect the Black to the terminal with all the other Blacks in it.

Connect the Red (or brown) to the terminal with the Switched Live (Black marked with red).

Stand back, turn on the power, and verify that the lamp in this room now works, under the control of the light switch.

Have another mug of tea.

Turn off the power, and start to fix everything up in the ceiling. You can relace your connector strip with a ceiling rose. Modern ceiling roses have plenty of terminals inside them. Use your cable sketch and your markings to ensure you put everything in the correct terminal, especially the switched Live. It is incorrect location of the switched live that causes a lot of faults after amateurs have changed lamp fittings.

Test again, have another mug of tea, send me £25 and go to bed.

I was thinking of putting all this in the Wiki but I see there is already a similar one there //wiki.diynot.com/electrics:lighting:problems:blackswlive

Does anyone think it is worth putting this one in as well?

You can do if you like

I haven't done much with the wiki of late. We will need to get our act together in the new year when the 17th edition comes out
Maybe Mr Admin will buy us all a new set of guidance notes and regs for Xmas

JohnD said:

ask your wife to spank you for carelessness

Click to expand...

I often do, even when I've done nothing wrong, but, frustratingly, she doesn't discipline me...

Thank you for the replies.

I am going to follow your instructions over the weekend and let you know how I get on.

Thanks a lot John for all of your time and help.

Best regards


Mark

I have just finished wiring up as described and I have the following problem:

Hall way light:

works fine on the correct switch as before and turns on and off.

Landig light:

I have to have the hall way light on for it to work, but it turns on and off on the correct switch whilst the hall way lght is on. Without the hallway light on there is no response from the landing light.

I have a double light switch at the bottom of the stairs and a single ligh switch on the landing if that helps at all.


Best regards



Mark

uggitt said:

Landing light:

I have to have the hall way light on for it to work, but it turns on and off on the correct switch whilst the hall way lght is on. Without the hallway light on there is no response from the landing light.

Click to expand...

Sounds as if one of the cables from the bunch in the hall ceiling rose, is the supply to the landing. Somehow it seems to be being fed from the switched live instead of the permanent live.

Using your multimeter, see if you can detect which cable goes to the landing, by having an assistant operate the landing light switch while you look for continuity appearing/disappearing across a red and black pair (with the power off). You will need an ordinary light bulb in the landing fitting for this to work, and due to the resistance of the filament, the continuity will not be as high as when you found the hall switch cable yesterday. you will have to separate all the cores out into your plastic connector strip, so that no core is connected to any other core, to trace it.

Assuming you have not altered anything at the switches, only at the ceiling rose, this should find it. If you have kept your sketch of cables and what they do, and marked them 1, 2, 3, 4 this should make the job easier. You may be able to see why I was so keen to label all the cables yesterday.