Power a masthead amplifier using lighting cable?

[Sprogginz]

I don't have any power sockets in my loft, just one light switch.

Would it be possible to power this masthead amplifier using the feed to the light switch?

If so, can I simply use a 3 pin power socket?

Thanks very much.

 

[PBC_1966]

Do you actually have a full feed to the switch? Remember that switches often have a single cable running to them with live and switched live, so there is no neutral present. But if you have a feed (live & neutral) coming into the switch, then another cable runs out from the switch to the loft light, you could run from the switch box to your amplifier.

Putting a regular 13A socket on a lighting circuit doesn't pose a safety risk, since the circuit is protected (normally) by a 5 or 6A fuse or MCB, but it's something many of us regard as "not nice," since there could come a time you (or somebody) tries to use that loft socket temporarily for something higher powered, even though fitted for the amplifier.

Looking at the particular unit you have in mind, it doesn't have a plug-type power unit, just a regular 13A plug, so a "cleaner" option would be either (a) fit a BS546 (round-pin) 5A socket on the lighting circuit and change the plug on the amplifier to match, or (b) fit an FCU and wire the amplifier supply into it, using a suitable fuse in the FCU.

 

[Echo the husky]

Or C, the easy option, put the power supply behind one of the tellies where it is designed to go!

 

[Sprogginz]

Or C, the easy option, put the power supply behind one of the tellies where it is designed to go!

It's not one of those.

 

[Sprogginz]

Do you actually have a full feed to the switch? Remember that switches often have a single cable running to them with live and switched live, so there is no neutral present. But if you have a feed (live & neutral) coming into the switch, then another cable runs out from the switch to the loft light, you could run from the switch box to your amplifier.

Putting a regular 13A socket on a lighting circuit doesn't pose a safety risk, since the circuit is protected (normally) by a 5 or 6A fuse or MCB, but it's something many of us regard as "not nice," since there could come a time you (or somebody) tries to use that loft socket temporarily for something higher powered, even though fitted for the amplifier.

Looking at the particular unit you have in mind, it doesn't have a plug-type power unit, just a regular 13A plug, so a "cleaner" option would be either (a) fit a BS546 (round-pin) 5A socket on the lighting circuit and change the plug on the amplifier to match, or (b) fit an FCU and wire the amplifier supply into it, using a suitable fuse in the FCU.

Thanks very much.
Wasn't sure if it was legal to connect it to a lighting circuit.
I'm pretty sure it's live & neutral but I'll check.
I was going to put a 3 pin plug socket if it was possible but I like your idea of a FCU.
Thanks again.

 

[Taylortwocities]

I'm pretty sure it's live & neutral but I'll check.

You'll need an earth too!

Ps just because the wires are coloured black and red, or brown and blue, does not necessarily mean they are line and neutral!

 

[davelx]

I'm pretty sure it's live & neutral but I'll check.

You'll need an earth too!

Ps just because the wires are coloured black and red, or brown and blue, does not necessarily mean they are line and neutral!

If all you have behind the switch is a single cable with the L & N cores connected to the switch (and, hopefully, the earth connected to the backbox or switch earth terminal if present), then you don't have a neutral there. Post a photo of the connections if you have any doubts.

 

[ban-all-sheds]

I'm pretty sure it's live & neutral but I'll check.

Don't assume that a black or blue conductor will be neutral.

 

[PBC_1966]

Wasn't sure if it was legal to connect it to a lighting circuit.

It's perfectly legal in both the sense of the statutory requirement to make "reasonable provision for safety" (which is all the law demands) and legal in the sense of complying with the (non-mandatory) requirements of BS7671 - "The Wiring Regs."

Althouh nominally called lighting circuits, they can feed anything besides lights subject to the total load connected to the circuit not being excessive. Exhaust fans, intruder and fire alarm systems, TV preamplifiers and similar low-power devices are very commonly connected to "lighting" circuits.

 

[Sprogginz]

...et voila

Would that be safe to say I can use that?

 

[Echo the husky]

No, that blue is switched line not neutral.

 

[PBC_1966]

But if you trace that cable back to the light fitting or junction box, you should be able to find a feed there. It's generally pretty easy to find somewhere to tap for things like this in an open attic space.

 

[bernardgreen]

It's not one of those.

Would it be possible to power this masthead amplifier using the feed to the light switch?

The amplifier in the picture is powered by 12 volts sent UP one of the co-ax cables that come from the mast head amplifier outputs. ( Signal OUT power IN )
.
The PSU goes behind any one of the televisions.
The lead from the mast head amplifier goes into one of the sockets on the PSU ( SIGNAL IN 12 volts OUT ) and a lead from the other socket on the PSU connects to the TV aerial socket.

 

[flameport]

It's not one of those.

Picture, description, reviews and questions on the site linked to all state otherwise.

 

[PBC_1966]

You could put the power unit behind the TV at some outlet location, but there's no reason you couldn't mount it somewhere else out of the way either.