Hello all, I'm thinking of wiring a plug socket in the loft

[gastra]

The problem is the only wires up there are for the light bulb, Would it be possible to switch off the mains split those (correctly ofcourse) and have power from there aswell as for the light?
Or is there another way? any help much appreciated

 

[17thman]

is it for a tv booster/splitter?

 

[ricicle]

If the socket is for anything other than a TV amplifier then you cannot spur from the lighting circuit. If so you will need to connect to the permanant L, not the switched L (along with N + E)

 

[gastra]

Its for a laptop psu i was hoping i could open up the switch, join two more wires wire in a plug socket and that would work. Is that not the case?
At the moment all there is up there is a 60 watt light bulb and a switch its where i get the best signal from 3g and where i can get away from the other half so much needed

 

[mfarrow]

IME there's not a great deal of power required for a PSU, so you shouldn't experience any problems. Ensure that the plug has a 3A fuse to discriminate with the ~6A lighting circuit breaker - you don't want any fault with your PSU upsetting your only light source.

If there's only one cable going to the switch, then you don't want to join there.

Can you find a junction box for the lighting, or access the rose for the fitting? Usually you'll find 4 terminals - connect to the one with 2+ red/browns for the line and the one with 2+ black/blues for the neutral. The Earth should be obvious enough. Don't connect to the line wire for the lamp, otherwise the socket will only work when the light is on.

 

[sparkwright]

You should consider getting the supply from the socket circuit. This will involve getting a cable up to the loft. Is there something like an airing cupboard that you can use to install the cable in so it's out of sight?

Do you know the rules on what cable to use, and how to spur off/extend ring circuits?

 

[gastra]

no access to a power socket :/ can it still be done?

 

[bernardgreen]

Its for a laptop psu

Many laptop power supply units have an in rush current (at switch on) that is a couple of amps for a 100 milliseconds or so. If fed from a lighting circuit then the total of this in-rush current added to the current for lamps might be enough to trip the 6 Amp MCB for the lighting circuit.

Better to bite the bullet and bring a feed up from the ring circuit.

If you are working up there then the last thing you want is to be plunged into darkness and then unable to find the safe way out of the attic.

 

[gastra]

Lighting isnt an issue as there is a skylight and its mainly light when i get up there and the ladders stay down leaving light from the landing too so finding a way out is no problem its just getting the laptop plugged in thats a priority i cant find an access point for any other live feed and dont want to destroy the house feeding wires all over :/

 

[holmslaw]

..

 

[bernardgreen]

leaving light from the landing too

It is 7 pm in the winter months and the MCB for the lights has tripped.

What light is there now. torch or moonlight ?

 

[flameport]

no access to a power socket :/ can it still be done?

Yes, you use the battery in the laptop, so no power supply required.

 

[Risteard]

Ensure that the plug has a 3A fuse to discriminate with the ~6A lighting circuit breaker - you don't want any fault with your PSU upsetting your only light source.

Do you think a 3A BS 1362 fuse will provide discrimination/selectivity with a 6A Type B BS EN 60898 circuit breaker?

 

[mfarrow]

Do you think a 3A BS 1362 fuse will provide discrimination/selectivity with a 6A Type B BS EN 60898 circuit breaker?

I haven't got both graphs to hand, but I wouldn't have thought it any worse than a 13A BS 1362 fuse and a 16A/20A breaker.

Admittedly you'll often be hard pressed to find a fuse/breaker combination which didn't trip both under fault conditions, but we have to believe what the manufacturer's tell us otherwise we'll all be installing fuse holders in DBs still.

Inrush of the PSU on the circuit breaker is one to consider. I haven't got an example of where is has/hasn't been an issue but it would be worth considering getting an electrician to assess the option of installing a Type C breaker in place of the present one.

 

[sparkwright]

There must be some way of coming off the socket circuit.