Mains Power in the Loft

jghal

I want to put an TV aerial amplifier in the loft. The amplifier needs mains power and the only mains power in the loft is the lighting circuits.

Can I tap off the lighting circuit to power this amplifier.

I know a reasonable amount about electrics etc and know what to look for re mains feeds/switch wires etc to the lights.

I live in Scotland so part P regs etc are not an issue.

How do I do this safely ? All assistance appreciated

cheers :beer:

polybear

Three questions:
1. What is the power requirement of the amplifier? (i.e. how much power or current in Watts or Amps is drawn from the 240v ac supply?).
2. Does your lighting ring-main in the loft have an earth provided, which is actually connected and not merely for show?
3. Does the amplifier actually need an earth connection? (it may be double insulated).

The other option may simply be to fit the amplifier at the other end of the aerial cable (i.e. at the input to the tv).

Polybear

jghal

Hi polybear

the current draw is low - if it is permissale to tap into the lighting circuit I would fit a fused spur (fused at 3A or less) between the lighting circuit and the new socket.

I don't know about the earth in the loft yet, but I am sure the amplifier plug has an insulated earth pin so may not be an issue as long as it is only the amplifier that is ever plugged into the new socket.

I want to run 3 TVs off the aerial (all in different rooms) so putting the amplifier at the aeriel end is the best option for this.

My major concern is safety - someone else could go into the loft and plug in some power tools etc (one of the reasons for the 3A fuse - so that the power tool would blow the fuse and not work through the lighting circuit).

I have no problem with making the new setup work, I just want to make sure it is permissable to do this and that it is safe

thanks

YorkshireBoy

jghal wrote:

My major concern is safety - someone else could go into the loft and plug in some power tools etc (one of the reasons for the 3A fuse - so that the power tool would blow the fuse and not work through the lighting circuit).

As an electrical engineer, I'd suggest you don't install a 13A socket on the lighting circuit.

Instead, fit a 1A fuse in the fused (DP switched) connection unit, cut the plug off the amplifier, and connect the cable directly to the fused connection unit.

jghal

Good post YorkshireBoy - hadn't even occured to me to cut the plug off the amplifier and use a switched/fused spur.

But my original question still stands - is this allowed ?

YorkshireBoy

jghal wrote:

Good post YorkshireBoy - hadn't even occured to me to cut the plug off the amplifier and use a switched/fused spur.

I'm no radio engineer, but read your instruction manual to see if there is any suppression/surge arrestor etc fitted within the plug.

But my original question still stands - is this allowed ?

Yes, if installed as I described above.

polybear

Using a 1A fused supply is a good suggestion; cutting the plug off and wiring it in is another, assuming the plug isn't one of those combined plug/transformer units.

Depends what you mean by "is this allowed?". Someone, somewhere is bound to quote the 16th Edition wiring regulations and say it isn't allowed. The important question is "is this safe?" I can see no problems whatsoever (HNC in electronics & electrical engineering) so long as you take appropriate precautions to ensure that the current drawn from the circuit isn't excessive and that all wiring workmanship is satisfactory. Making sure that the spur cannot be used for other purposes is another sensible precaution. Another thing I would do is make sure that the amplifier is well ventilated (i.e. don't bury it in loft insulation!).

If the amplifier runs quite happily on a 1amp spur, then it's taking no more than 240watts. My local electrical dealer sells 200watt bayonet cap bulbs that can be fitted to any ceiling lighting pendant. You could also fit a combined light/fan unit to the ceiling (180 watt, assuming 3 x 60w bulbs, plus a few more watts for the fan unit). Thinking of it in those terms, what's the difference?

Polybear.