60w light in the loft where to pick up mains for supply

[djmarkyboy]

Hi there,
I am trying to wire up a 1-2wy switch for a 60w light in the loft. Now I need to pick up a mains supply. Where is the correct place to branch into for the mains. I have tried the top of stairs ceiling rose for a mains supply but I keep blowing fuses or its switched on via landing light switch and as soon as I switch the loft switch it blows the fuse.

Any help with this would be most appreciated coz I am a newbie

djmarkyboy

 

[griffta1]

Sounds like your lighting circuit is approaching it's maximum capacity. How many lights have you got on the circuit that your landing light is on? (i.e. what is the total wattage) and what fuse/mcb is fitted for this circuit at the consumer unit?

 

[ban-all-sheds]

That's not the reason - FHS think about the characteristics of protective devices. There is absolutely no way that the circuit could be loaded to a level where the protective device never operates and then operates instantly when another 250mA is added.

Also the "I keep blowing fuses or its switched on via landing light switch and as soon as I switch the loft switch it blows the fuse" should give you a clue that djmarkyboy has made a mistake with his wiring.

dj - look at the For Reference topic for diagrams of how ceiling roses are wired - it should then be obvious how to add another light into the circuit.

 

[griffta1]

fair point

 

[djmarkyboy]

Sounds like your lighting circuit is approaching it's maximum capacity. How many lights have you got on the circuit that your landing light is on? (i.e. what is the total wattage) and what fuse/mcb is fitted for this circuit at the consumer unit?

I am unsure the specs of lights etc on circuit because I am beginner when it comes to electrics. The mcb amps I am unable to verify because I am not at home.

markyboy

 

[johnny_t]

I'm not the first person to say this, but your problem is not one of current consumption (well, not in the way you refer to here) but is because it is wired wrongly.

If your loft light comes on when you switch on the landing light, it means that it is wired between the switched live and neutral of the landing light,

If the fuse blows when you flick the switch, then the switch is connected directly between a live and neutral.

The chain needs to go from permanent live at the ceiling rose, to one side of a switch, out the other side, to one side of the light, out the other side and back to the neutral at the ceiling rose. Yours doesn't.

 

[djmarkyboy]

I'm not the first person to say this, but your problem is not one of current consumption (well, not in the way you refer to here) but is because it is wired wrongly.

If your loft light comes on when you switch on the landing light, it means that it is wired between the switched live and neutral of the landing light,

If the fuse blows when you flick the switch, then the switch is connected directly between a live and neutral.

The chain needs to go from permanent live at the ceiling rose, to one side of a switch, out the other side, to one side of the light, out the other side and back to the neutral at the ceiling rose. Yours doesn't.

Would it help if I sent you images of a) ceiling rose with wires(I am trying to take supply from this) and b) the switch I am using

Many thanks again
djmarkyboy

 

[Steve]

you need to find the permenant live and neutral in this ceiling rose. Usually there are 2 or 3 red or brown wires going to the same terminal block (none to the light though), this is the permenant live. See for reference sticky thread. Lots of diagrams there.

 

[ban-all-sheds]

Would it help if I sent you images of a) ceiling rose with wires(I am trying to take supply from this) and b) the switch I am using

Not really - we know how they look - you need to look in For Reference at how they should be wired, how the lighting wiring/switching system in your house hangs together etc.

How have you tried to wire it up?

 

[djmarkyboy]

How have you tried to wire it up?[/quote]

I took the two live terminals posts to the left of the main live block in the middle of the rose and used the neutrals to the right of live main block in center of rose. Then I wired it to a 2 way light switch twisted live pairs to com and twisted neutral pairs to 1 wy terminal on switch


djmarkyboy

 

[johnny_t]

A diagram of what you think is going on with your circuit would help.....

 

[Steve]

2 way light switch twisted live pairs to com and twisted neutral pairs to 1 wy terminal on switch

1st mistake. neutrals are never switched in lighting circuits - never connect them to a switch. ever. This is probably why the fuse was blowing. you are actually connecting live TO NEUTRAL when you flick the switch. you need a 1-way switch. unless you want 2 switches to control that light . . .

 

[ban-all-sheds]

I took the two live terminals posts to the left of the main live block in the middle of the rose and used the neutrals to the right of live main block in center of rose. Then I wired it to a 2 way light switch twisted live pairs to com and twisted neutral pairs to 1 wy terminal on switch

Stop and think for few minutes about what a switch must do in order to connect and disconnect an electrical supply to and from a light.

Then think about what will happen if you put the live and neutral wires into a switch.

. . . . .

At the end of the day you'll probably muddle your way to a solution to your immediate problem, but I worry that you won't really understand how or why.

If you plan to ever do any more electrical work, put this on your Christmas list:

http://www.amazon.co.uk/exec/obidos/ASIN/0852028172

you need a 1-way switch. unless you want 2 switches to control that light . . .

The 2-way switch you have will be fine - just use COM and L1 - ignore L2.