Can I Wire a Wall Mounted TV to a Light Fitting to Power it?


Postby Oxmanc » Fri Apr 10, 2015 5:51 am

Good Morning Folks,

I'm hoping this is not an entirely silly question, but I'm fairly new to DIY and have little knowledge regarding wiring.

My little girl is on the verge of toddling and has started taking an interest in the various cables around the television, so my plan is to put the TV up on the wall and get the cables out of the way. It's an old house with thick internal brick walls, and the wall I'd like to mount the TV on has a utility room on the other side. There is a light on the wall in the front room, and the wiring to it comes via a hole drilled though the wall which I can access from the other side. It has all 3 wires you would see at the back of a conventional plug socket.

Would it be dangerous to removed the light and use the cable to power the television?

Many thanks.
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Postby ericmark » Fri Apr 10, 2015 11:35 am

Wish I could simply say yes or no but not as easy as that.
1) Many pre-1960 houses have no earth to lights and need re-wiring if yours is one of these then it's a non starter.
2) The idea of separate circuits is that should something go wrong with TV it would not fuse the lights there has to be some consideration of over load as well.
3) Lighting circuits are normally just 5 or 6 amp where power circuits are between 16 and 32 amp it depends on the load already on the circuit and in theroy you should not fit a 13A socket to a lighting circuit because something else may get plugged in.

So general answer is no you should not use it. However many wall lamps are in fact powered from the power circuits through a fused connection unit. You can also use a FCU to limit the load which can be drawn so with a 6 amp lighting circuit using a FCU with a 2A fuse would reduce the chance of other equipment plugged in causing the lights to fail.

When looking at the power circuit we also have problems. In the UK we use the ring final system and two cables rated at 20 amp feed the sockets from a 30A fuse or 32A MCB. We are permitted to take one un-fused spur from any socket to feed an outlet device be it a single socket, double socket or FCU. But in many houses these rules have not been followed.

With a 16 or 20 amp fuse/MCB then there is not the same problem.

We also now have new rules and although you can use existing sockets any new ones must follow the new rules. This means any new socket or cable buried in the wall needs RCD protection. In many old houses it means before any new sockets are added the fuse box or consumer unit needs changing for a new consumer unit with RCD protection built in.

So must depends on your existing system. You say little girl so having RCD protection is really something you will want if not already installed. At the end of this year new rules are due to come in which will raise the price by a huge amount all new consumer units from next year will need to be steel so it would make sense to get it changed before the price goes up. Steel is to reduce fire problems when people leave screws loose but clearly an electrician should not leave any loose screws.

With shuttered sockets and RCD protection our system is one of the safest in the world however you would not believe how many people shove in silly bits of plastic into the sockets defeating the protection. In Germany for example they don't have shutters and also no fuses in plug and reversible plugs with some times no earth so for them the idea of plastic covers may make some sense but that's not the case in the UK. (See fatefully flawed http://www.fatallyflawed.org.uk/ )

But first thing it to find out what the light is fed from it may be it's already from the power circuit. Then inspect the fuse box/consumer unit and see if already RCD protected. Using a RCD FCU maybe you can still add a socket.

The point is also of course you can break all the rules and do anything you like and unless some one is injured your unlikely to get caught. But the whole idea is to make it safe for your daughter so you have to do a risk assessment. Any electrics altered should be tested and if you followed rules to the letter then there would be no DIY on electrics as the test gear costs so much. Clearly people do DIY and so one has to decide how far to go breaking the rules. We all do it I will often drive at 75 on a motorway but would not drive at 100 it's a case of risk assessment.

There are plug in testers with loop test at around £50 and personally I think that's a reasonable cost to test sockets. There are those without loop test at around £10 personally I don't think they are good enough. You have to decide how much DIY are you likely to do and should you get a Martindale EZ150 tester or is it better to get an electrician to do the job.

On the forums there is often a question should we say yes or no when we get the question "can I" in the main if following regulations to letter answer is no. But few follow regulations to the letter. So what I feel is if likely safe then go ahead. My house has an emergency light at top of stairs to see way down with power cut so if something trips my lights there is no real danger.

So do that risk assessment.
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Postby Oxmanc » Sat Apr 11, 2015 6:27 am

Good Morning,

Many thanks for your detailed reply, it's really appreciated.

The house has certainly been rewired in the last few years. We rent the property from the church that it is attached to and I'm happy to say they are the most pro-active and thorough landlords we have ever had! Not to mention happy for us perform DIY.

The fuse in the main box that powers this light does not power anything other than this particular lighting circuit. However, having read through your reply carefully I think it is best not to take any chances. I think I will remove the light fitting and use the drilled hole to run a power cable from a socket in the room behind the wall.

You do raise another point though that conflicts with another plan I had. So just to clarify, are you saying that by putting plastic covers into the plug sockets around the house I am actually making them more dangerous?

Thanks again.
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Postby ericmark » Sat Apr 11, 2015 8:35 am

[quote="Oxmanc"]
You do raise another point though that conflicts with another plan I had. So just to clarify, are you saying that by putting plastic covers into the plug sockets around the house I am actually making them more dangerous?

Thanks again.[/quote]
Yes our system has automatic shutters on the sockets. The plastic lumps has many problems first being they are not to BS1363 and the pins are often not to the required size. As a result they can damage a socket and cause it to over heat when used latter.

BS1363 also states what should be covered by the plug in the main so you can't get fingers between plug and socket and touch something live while inserting or removing. These plastic lumps again don't comply and often have holes which means it opens up access to the live parts rather than cover them up.

It has been found children see these covers as toys and seem to be attracted to them. Unlike the proper plug to BS1363 there have some flexibility and can be inserted the wrong way around and so open up the shutters.

When doing inspection and testing I put them all in a bag and label them "Not to BS 1363 do not use in 13A sockets". I want to just bin them but have to let the customer do that.

There is one problem with BS 1363 and that's with extension leads. It allows the earth pin to be too close to the edge and so a 13A plug can be put in the wrong way around. The square 4 way extension leads are OK but many of the long bar type will allow plug to be fitted wrong way around.

However you would have to be daft to try it. The socket covers were first made for German sockets which don't have shutters like ours. And then since they sold well in Germany they made a British version and some councils actually insisted that people who looked after other peoples children had them fitted. Clearly in error and by now I would hope they have learnt the error of their ways.
ericmark
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