spur & 'stuck' back-boxes...

[NC]

Hi all, I have run cat5 and coax up into the loft - cutting out the plasterboard in various rooms and flush mounting metal boxes within the plasterboard walls. However, I now need to get power up there. I dont want to tap into the lighting circuit (which I do have access to.. but been told its a bad idea..??). I would like to run a spur from one of the first floor bedrooms, up into the loft within the plasterboard walls as I have done with the cat5/coax. However, the back boxes holding the current mains sockets seem to be stuck - they are surrounded by plaster within the hole and I cant get them out to get a spur connected and routed up into the loft. Any tips on how to get these boxes out ?? Can I just go at them carefully with a chisel and chip away at the plaster that is holding them in place (with the risk of going through the mains cable if I'm not careful) ?? An alternative is to wire in a socket both in a bedroom (this end fused?) and the loft and use a couple of standard plugs to bridge from an existing socket - is this a reasonable idea ? (albeit ugly, but I should be able to hide it somewhere).

[Dave Plowman (News)]

Depends on what you want the 'power' for. If to run a DA etc, then feeding it from the lighting circuit is perfectly ok - they take far less current than the smallest light bulb. Likewise an ADSL router.

[Set Square]

If they're metal boxes, chances are they will have been screwed to the framing before the plasterboard was skimmed - so the skimming will slightly overlap the edges. To remove the boxes, you will need to chop back the excess plaster skim very carefully, and then remove any holding screws.

If you are suggesting using a cable with a 13A plug on *both* ends, this is a very *bad* idea - because the remote plug can be live when not plugged in, and some fool may inadvertently cop hold of a live pin!

How much power do you need in the attic. If you are only wanting to power small electronic devices, I see no problem with tapping into the lighting circuit. But use 5A round pin plugs and sockets to prevent anyone using the supply for anything bigger.

[Alan]

Don't even think about doing this!! This is potentially **VERY** dangerous.

What do you need to power in the loft? If just small stuff like an aerial amp / network hub / router then feeding it from the lighting circuit is fine.

Alan.

[NC]

OK - fair point - never thought of that !! It will be used for small things - a router and wireless bridge to start with, but maybe a PC server in the future. How do I tap into the lighting ?? (I am competant, just never done this before)

[Alex]

After that suggestion competent is the last thing I would call you. Leave it alone and get an electrician it may cost more but at least you should still be alive in the new year

[Andy Hall]

If you were just going for one or two 10W devices like a router and a Wifi access point, that is one thing and a lighting circuit is reasonable in terms of load. However, noting Dave's suggestion of 5A sockets to prevent other things being plugged in, most of these small ethernet devices have a wall wart supply fashioned as a 13A plug. Given that, you would have to arrange something like a multiway socket and then you are back to square one.

Also, once you start adding PCs it's pushing the envelope a bit for a lighting circuit. Probably it would work OK and the fuse wouldn't blow or breaker trip, but it is going rather beyond the original intent.

To be honest, running a proper spur would be the right thing to do if this is the eventual intention whether you do it now or later.

[NC]

Fair point. But in my defense, that was something that I thought of as I typed and had put NO thought into.

[NC]

I agree - and would like to go down this 'proper' route. Any thoughts on getting the 'stuck' boxes out to enable me to connect the spur and route the cable ?

[John Rumm]

If you modify it a little - plug on one end, socket on the other - it actually becomes a viable solution. Wire a multiway extension lead type socket to a suitable flex, and then route that back to a socket location below and stick a plug on it.

[NC]

ah ha, thats what I meant !! Typo in the original post - I knew I couldn't have *meant* to be that stupid ! I think this will be the easiest option for me - and better than going into the light circuit. I can hide the new socket away behind some wardrobes. Thanks for confirming I'm not *that* insane !

[John Rumm]

The boxes (if they are the metal flush mounting type) will probably be fixed by screws into the wall or a nogging between the studs, plus they will also be held in place by the plaster skim rount their periphery. Remove the screws and chip away the plaster and it will be free (well only held by the wires...)

Do you need to free it though? Could you not just punch out another blanking disc on the top of the socket? To feed a wire up from the socket you can use the lid of a bit of mini trunking as a fish tape.

[NC]

It looks like the plaster that has overlapped has fully covered all of the disks. The only way I can be sure to get a wire into the box is to take it out, clean the hole and re-mount it to the brickwork.

[John Rumm]

Are you sure this is a stud wall then? Sounds more like it has been sunk into the plaster of a blockwork/brick wall. In which case gettting a knockout out fo the box is only the start of your problem - you will also need a chase up the wall to lay the cable in.

[NC]

its dot and dab onto brickwork. I can use the gap however to route cables - and have done using routing rods to get cat5 and coax into the loft.

[Andy Hall]

.... or.....

Run a standalone circuit starting from a fused/(plus possibly switched) spur unit located near the existing socket and fit with 13A fuse. Wire from this to the loft in standard 2.5mm T&E and fit as many double sockets on the loft end as desired.

Fit a length of flex and a plug to the spur unit's "supply" side and plug into existing socket.

---Later----

Upon decorating etc. Wire a short length of cable from the existing socket to the spur unit to replace plug and flex.

A little unconventional, but is and will remain completely safe and nothing needs to be redone later.

[NC]

yep - thats the way I'll go; and if I can get it done tonight while the wife it at work, and ten get it hidden behind the wardrobes.. she'll never know and never complain about me making a mess of the nice new house! One point though - I thought I could only put one double socket off a spur ?? Or can this be multiple as long as its fused ??

[John Rumm]

In which case you should be able to chip away some of the plaster/ plasterboard above the socket and get the other knockout out (screwdriver on it and a tap with a hammer usually works!).

If you are confident there are no wires where you want to chip away, then a couple of closely spaced holes with a drill should clear the space above the knockout.

[Andy Hall]

Exactly. As long as you have the spur unit (which can't have more than a 13A fuse) this is allowed. Without the spur unit, it would be a max of one double socket on the end.

For future reference, another way to wire a circuit if starting from the consumer unit, is to use a radial circuit. You can use a single run of 2.5sqmm cable and daisy chain as many sockets as you like

*provided* that the circuit has a 16A fuse or MCB at the consumer unit.

[Dave Plowman (News)]

If you use an FCU at the start of the spur you can have as many sockets as you wish.