|
electrical socket in the loft ?
Just a quick question to any electrical experts in here.
I want to put a plug socket in my loft, but i'm not sure where to take it from, as there are no ring main power cables up there, only lighting cables. There is however, the enormous cable for my shower!, (10mm T&E I think) which i'm sure could easily supply a single power socket. The thing is, I can't seem to find a junction box to take this size cable (well, not at B&Q, Wickes etc.), although I haven't tried a merchants yet. Also, is this the right way to join to a cable this size, or indeed, is this meant to be done at all (i've been told, not by an expert mind, that you should never run anything else from a shower cable, only the shower). The shower is 9.5 kW, so the 10mm cable must have plenty left for a power circuit, i'd have thought). I guess the alternative is to take a spur from a socket in one of the bedrooms etc., but I don't want to upset any decorating. I just want to locate a suitable source already i the loft. Perhaps i'm going about this all the wrong way, if so can antone suggest anything else (from the available cables in th loft). I'm aware of the changes to wiring regulations recently, but not sure if this applies to what I want to do, if so then I'll get someone qualified to do it. Graham |
graham wrote:
Just a quick question to any electrical experts in here. I want to put a plug socket in my loft, but i'm not sure where to take it from, as there are no ring main power cables up there, only lighting cables. No. Lighitng circuit rated at 6A. 13A socket rated at 13A. Also, if your house has TT earthing, the lighting circuit might not be protected with a 30mA RCD, which is required for sockets on a TT installation. There is however, the enormous cable for my shower!, (10mm T&E I think) which i'm sure could easily supply a single power socket. The thing is, I can't seem to find a junction box to take this size cable (well, not at B&Q, Wickes etc.), although I haven't tried a merchants yet. Also, is this the right way to join to a cable this size, or indeed, is this meant to be done at all (i've been told, not by an expert mind, that you should never run anything else from a shower cable, only the shower). That is correct. The shower is 9.5 kW, so the 10mm cable must have plenty left for a power circuit, i'd have thought). Not much. A 9.5kW shower is 39.5A; 10mm cable is rated 43A in thermal insulation, which may be the case in the loft. That is *without* correction for ambient temperature, which may well require a derating factor in a loft, of perhaps 0.71. So your 10mm cable may actually be under-rated for the shower. I guess the alternative is to take a spur from a socket in one of the bedrooms etc., but I don't want to upset any decorating. I just want to locate a suitable source already i the loft. Don't you have any fitted cupboards you can take a cable up inside? Provided it is not in an area subject to physical damage and is visible, surface clipped cable is perfectly acceptable in a domestic installation. Take it neatly along a skirting board and up a doorframe, then through a neat hole drilled in any cornice, and leave some slack at each end, so that the cable can be concealed when the room is next decorated. Even taking it up the side of a window can mean it is concealed by floor-to-ceiling curtains in some cases. Owain |
On Tue, 31 May 2005 16:49:50 GMT, graham
wrote: Just a quick question to any electrical experts in here. I want to put a plug socket in my loft, but i'm not sure where to take it from, as there are no ring main power cables up there, only lighting cables. There is however, the enormous cable for my shower!, (10mm T&E I think) which i'm sure could easily supply a single power socket. The thing is, I can't seem to find a junction box to take this size cable (well, not at B&Q, Wickes etc.), although I haven't tried a merchants yet. Also, is this the right way to join to a cable this size, or indeed, is this meant to be done at all (i've been told, not by an expert mind, that you should never run anything else from a shower cable, only the shower). The shower is 9.5 kW, so the 10mm cable must have plenty left for a power circuit, i'd have thought). I guess the alternative is to take a spur from a socket in one of the bedrooms etc., but I don't want to upset any decorating. I just want to locate a suitable source already i the loft. Perhaps i'm going about this all the wrong way, if so can antone suggest anything else (from the available cables in th loft). I'm aware of the changes to wiring regulations recently, but not sure if this applies to what I want to do, if so then I'll get someone qualified to do it. Graham Personally I wouldn't interfere with the shower feed in any way. You don't happen to have a socket in an airing cupboard do you ? They used to be a common feature. Andy |
On Tue, 31 May 2005 16:49:50 GMT, graham
strung together this: Just a quick question to any electrical experts in here. Er..... I want to put a plug socket in my loft, but i'm not sure where to take it from, as there are no ring main power cables up there, only lighting cables. There is however, the enormous cable for my shower!, No, no and thrice no. Don't do it, full stop. Also, is this the right way to join to a cable this size, or indeed, is this meant to be done at all (i've been told, not by an expert mind, that you should never run anything else from a shower cable, only the shower). Correct, don't do it. The shower is 9.5 kW, so the 10mm cable must have plenty left for a power circuit, i'd have thought). Stop thinking, it's ot going to do any of us any good. "Assumption is the mother of all **** ups". I guess the alternative is to take a spur from a socket in one of the bedrooms etc., but I don't want to upset any decorating. I just want to locate a suitable source already i the loft. Not so much an alternative, as the only correct way to do it. You must have a cupboard or wardrobe somewhere with a socket behind it or backing onto it. You can easily drill through from a suitable socket, up through a cupboard and into the loft to a socket. If not, just whack a length of trunking up the wall as a temporary job and sink it in the wall next time you decorate that wall. -- SJW Please reply to group or use 'usenet' in email subject |
In article ,
Owain writes: graham wrote: Just a quick question to any electrical experts in here. I want to put a plug socket in my loft, but i'm not sure where to take it from, as there are no ring main power cables up there, only lighting cables. No. Lighitng circuit rated at 6A. 13A socket rated at 13A. Also, if your house has TT earthing, the lighting circuit might not be protected with a 30mA RCD, which is required for sockets on a TT installation. Minor nit, but the RCD for protecting all socket outlets in a TT system does not need to be limited to 30mA (it isn't there to protect against electrocution). -- Andrew Gabriel |
Quote:
|
"wig" wrote in message
... I'm aware of the changes to wiring regulations recently, but not sure if this applies to what I want to do, if so then I'll get someone qualified to do it. Graham I'd run it from a lighting cable. What is the socket going to be used for? and how often? Regulations wise, if it comes from the bathroom, I believe Part P covers it and it must be installed by an electrician. However, I don't believe any electrician would take it from your shower feed. Would it be difficult just to take a channel up a wall and into the loft from a wall socket and then plaster/paint/paper over it? AFAIK, you shouldn't use the lighting circuit at all, as even if you don't, a future person could attach something of high load and cause a fire. I'm no electrician though so I'm sure there'll be a flood of answers from those who are soon enough ;) a |
al wrote:
AFAIK, you shouldn't use the lighting circuit at all, as even if you don't, a future person could attach something of high load and cause a fire. But any load higher than 5 or 6 amps would trip/blow the lighting circuit's MCB or fuse, so I can't see how it would be dangerous ? That's not to say it's reg-compliant ! The only safety issue (ignoring the regs etc) would be the possible lack of RCD protection. -- Mark Please replace invalid and invalid with gmx and net to reply |
No. Lighitng circuit rated at 6A. 13A socket rated at 13A. Also, if
your house has TT earthing, the lighting circuit might not be protected with a 30mA RCD, which is required for sockets on a TT installation. Minor nit, but the RCD for protecting all socket outlets in a TT system does not need to be limited to 30mA (it isn't there to protect against electrocution). Minor nit v2.0. The lighting circuit should be protected by an RCD in a TT earthed house anyway. Christian. |
On Wed, 01 Jun 2005 09:04:58 +0100, Mark Carver wrote:
al wrote: AFAIK, you shouldn't use the lighting circuit at all, as even if you don't, a future person could attach something of high load and cause a fire. But any load higher than 5 or 6 amps would trip/blow the lighting circuit's MCB or fuse, so I can't see how it would be dangerous ? That's not to say it's reg-compliant ! The only safety issue (ignoring the regs etc) would be the possible lack of RCD protection. Assuming someone has not uprated the fuse/mcb !!! Dave |
Mark Carver wrote:
al wrote: AFAIK, you shouldn't use the lighting circuit at all, as even if you don't, a future person could attach something of high load and cause a fire. But any load higher than 5 or 6 amps would trip/blow the lighting circuit's MCB or fuse, so I can't see how it would be dangerous ? That's not to say it's reg-compliant ! The only safety issue (ignoring the regs etc) would be the possible lack of RCD protection. Maybe.. But not straight away, they take time to trip and even when they do the chances are the cable has heated up considerably. So if a future home owner does this on a regular basis he may damage the cable by heating it too much. Eventually you'd get a short which may not instantly blow a fuse (say if it's been replaced with one of the wrong rating to stop it blowing!) and then you get your fire. Another reason I think this may be a bad idea is if you get a novice DIY-er who wishes to say install a double socket, he goes to his CU and switches off the ring marked 'upstairs plugs' or whatever. So when he thinks it's dead... It may not be. Same may go for a shower spur too. Of course this is all hear-say by me who's electrical knowledge is non-professional. -- Regards, Aaron. |
Aaron wrote:
Mark Carver wrote: al wrote: AFAIK, you shouldn't use the lighting circuit at all, as even if you don't, a future person could attach something of high load and cause a fire. But any load higher than 5 or 6 amps would trip/blow the lighting circuit's MCB or fuse, so I can't see how it would be dangerous ? That's not to say it's reg-compliant ! The only safety issue (ignoring the regs etc) would be the possible lack of RCD protection. Maybe.. But not straight away, they take time to trip and even when they do the chances are the cable has heated up considerably. So if a future home owner does this on a regular basis he may damage the cable by heating it too much. Eventually you'd get a short which may not instantly blow a fuse (say if it's been replaced with one of the wrong rating to stop it blowing!) and then you get your fire. Another reason I think this may be a bad idea is if you get a novice DIY-er who wishes to say install a double socket, he goes to his CU and switches off the ring marked 'upstairs plugs' or whatever. So when he thinks it's dead... It may not be. Same may go for a shower spur too. Of course this is all hear-say by me who's electrical knowledge is non-professional. Yes, I'm not advocating leaving such an arrangement for any future house owner, such a thing should obviously be removed if you sell the house, but for one's own use, under your own control etc, I see nothing wrong. Of course should your house burn down due to a totally unrelated cause, and the socket connected to the lighting circuit is found by investigators, it might well invalidate your insurance claim. :-) -- Mark Please replace invalid and invalid with gmx and net to reply |
"dave stanton" wrote in message ... On Wed, 01 Jun 2005 09:04:58 +0100, Mark Carver wrote: al wrote: AFAIK, you shouldn't use the lighting circuit at all, as even if you don't, a future person could attach something of high load and cause a fire. But any load higher than 5 or 6 amps would trip/blow the lighting circuit's MCB or fuse, so I can't see how it would be dangerous ? That's not to say it's reg-compliant ! The only safety issue (ignoring the regs etc) would be the possible lack of RCD protection. Run it through a fused connection unit with a 5amp fuse, thus there are 2 fuses protecting the socket. yes some could uprate both fuses - but then again someone could re wire the socket completely. |
O
Run it through a fused connection unit with a 5amp fuse, thus there are 2 fuses protecting the socket. yes some could uprate both fuses - but then again someone could re wire the socket completely. Still not good practice though. Dave |
"Mark Carver" wrote in message ... But any load higher than 5 or 6 amps would trip/blow the lighting circuit's MCB or fuse, so I can't see how it would be dangerous ? That's not to say it's reg-compliant ! The only safety issue (ignoring the regs etc) would be the possible lack of RCD protection. That's true enough. Still not the best thing to do. If a wiring inspection were done when you go to sell, I'm sure it would be pointed out as a "fault". a |
al wrote:
AFAIK, you shouldn't use the lighting circuit at all, as even if you don't, a future person could attach something of high load and cause a fire. Strangely.... When we re-wired our on-going project, there was a 2KW electric fan in the bathroom wired from the lighting circuit. Only initially realised this when all the downstairs (Bedroom/bathroom) lights were on and I flicked the heater on full. When we had an electrician round to quote on re-wiring I mentioned it and he said it's not uncommon and he's even done it himself on occasions! He didn't say how long ago mind. |
wig wrote:
I'd run it from a lighting cable. What is the socket going to be used for? and how often? Just Say No. Take a feed from an appropriate circuit. An appropriate circuit is one wot's got other sockits onit. Not the shower, not the light. Either one of those risks overloading the cable - and for those who believe that an MCB rated at 6A will instantly blow if you pull 6.01A, 6.1A, or 7A - no, it won't. It'll let 9-10A pass for 15-20 minutes at least. *If* you're lucky, the lighting cable's 1.5mmsq and can dissipate heat easily, so drawing 9A (full lighting load + 1kw fan-heater warming you in the loft) won't matter at all. If it's wired in the more normal (and cheaper, so bound to be used in any mass-built house) 1mmsq, and passes through good thick thermal insulation for any substantial part of its run, it'll warm up good and proper. No, it won't burst into flames; yes, the PVC insulation *will* soften, and anywhere there's a bit of pressure on it or a bend in the cable, the softened insulation *will* flow slowly away, leaving bare conductors if you're unlucky. How are you for black cats and paired magpies? Similar thought tells you why putting a 13A socket on your shower cable is a no-no. Again, the cable and MCB/fuse have been sized for the shower you have (or for the shower that was initially installed; possibly replaced later by a higher-current model). If the shower's a dinky little 7.5kW job (draws 31A), and it's wired in 10mmsq because that's what the sparks had on the van that day, and it takes a thermally-kind route - no practical problem. (Still a Regs violation, of course.) If the shower's a 9.6kW job (40A), run on a 6mmsq cable which was OK for the previous one which a handyperson's replaced with the new whizzy model, running through thermal insulation so it's already running at or over the sustained-temp limit of 70 degrees, with a 40A or 45A MCB fitted by the same handydroid to Uprate the shower, and you fit a 13A socket on it, wh'appen when it's *really* cold oop in t'loft and you wind the fanheater up to 3kW, while someone else takes a shower? The current's now up to 52A. Your 40A MCB doesn't mind, it can pass that current for hours; your cable's insulation, on the other hand, is now enjoying new heights of devil-may-care flexibility... Y'see, the Regs is written to reduce - not eliminate, reduce - the need for detailed analysis, and so that almost all foreseeable installations which conform with them are safe in practice, in normal use *and* under fault conditions. Going beyond the envelope of the Regs puts you in territory where you *may* still be lucky, or you *may* not. Again, how many rabbit's feet do you have to hand? There's plenty of ways of arranging a 'temporary' safe-enough feed up to the loft, which others have already outlined - if it's genuinely occaisional use, a flex running up a corner of some room or up a built-in wardrobe or airing cupboard up to a 4-way extension block which you plug in to a handy-enough socket is safer than fannying about with putting 13A sockets on lighting or (shudder) shower circuits. Doing a surface run of cable as a spur - again, taking some aesthetically-acceptable route - with a good length of slack up in t'loft ready for when you next redecorate and can sink the cable properly into the wall, or run it through the studwork wall if that's how your place is built, is a fully Regs-conformant solution. In short, there's enough ways of doing the job properly which don't require wall butchery at an inconvenient time that there's no excuse for bodgery... Stefek |
Pete wrote:
Run it through a fused connection unit with a 5amp fuse, thus there are 2 fuses protecting the socket. yes some could uprate both fuses - but then again someone could re wire the socket completely. But will an FCU with a 5amp fuse blow as soon as 5amps of current is drawn through it? I'll bet it wouldn't, and an MCB is unlikely too until the circuit has been loaded for some time (unless you can get really quickly reacting ones). An RCD would not protect against over current here either, it'd only help if a fault were to arrise but the damage would already be done then... I personally don't think there is a great need for a socket in the loft, after all what could you need to run up there when you are not up there with it and can therefore use a drum extention lead. The only things I've ever used in a loft is a lamp, soldering iron and a power drill... All powered from an extention lead. I guess it's convinient but I'll bet the OP has an extention lead he can use anyway. -- Regards, Aaron. |
"Aaron" wrote in message
k... Pete wrote: Run it through a fused connection unit with a 5amp fuse, thus there are 2 fuses protecting the socket. yes some could uprate both fuses - but then again someone could re wire the socket completely. But will an FCU with a 5amp fuse blow as soon as 5amps of current is drawn through it? I'll bet it wouldn't, and an MCB is unlikely too until the circuit has been loaded for some time (unless you can get really quickly reacting ones). An RCD would not protect against over current here either, it'd only help if a fault were to arrise but the damage would already be done then... I personally don't think there is a great need for a socket in the loft, after all what could you need to run up there when you are not up there with it and can therefore use a drum extention lead. fine for occasional temporary use, not so good or convenient for longer term or frequent use. The only things I've ever used in a loft is a lamp, soldering iron and a power drill... All powered from an extention lead. I guess it's convinient but I'll bet the OP has an extention lead he can use anyway. Whereas I have an aerial distribution amplifier, 4 computers, a monitor, a KVM switch and a network switch permanently up in the loft. 2 double sockets come in very handy up there. Useful places, lofts. -- Richard Sampson mail me at richard at olifant d-ot co do-t uk |
Aaron wrote:
But will an FCU with a 5amp fuse blow as soon as 5amps of current is drawn through it? I'll bet it wouldn't, and an MCB is unlikely too until the circuit has been loaded for some time (unless you can get really quickly reacting ones). Well the MCB on my lighting circuit *always* trips when one of the kitchen spotlight bulbs fail, and last week did so when a 'vanilla' 60w lamp blew. The only things I've ever used in a loft is a lamp, soldering iron and a power drill... All powered from an extention lead. I guess it's convinient but I'll bet the OP has an extention lead he can use anyway. How would you arrange to power a loft mounted TV aerial booster amp ? -- Mark Please replace invalid and invalid with gmx and net to reply |
Mark Carver wrote:
How would you arrange to power a loft mounted TV aerial booster amp ? If it's got a flex, cut the plug off and wire it into a junction box on the lighting circuit. If it's the sort that has a plug as part of the case, things are more awkward. One suggestion has been to glue a single extension socket to the case, to connect to a length of flex/cable that can be wired in to the junction box. What is to be avoided is a 13A socket into which other things could be plugged. Although if one is running coax cable all round the house for a TV system it shouldn't be beyond the wit of man to run a spur up to the loft at the same time. Owain |
In article , Mark Carver
wrote: How would you arrange to power a loft mounted TV aerial booster amp ? Cut the plug off and hardwire into a 5A switched spur from the lighting circuit. You will hardly notice the load. -- AJL Electronics (G6FGO) Ltd : Satellite and TV aerial systems http://www.classicmicrocars.co.uk : http://www.ajlelectronics.co.uk |
In article ,
Owain writes: Mark Carver wrote: How would you arrange to power a loft mounted TV aerial booster amp ? If it's got a flex, cut the plug off and wire it into a junction box on the lighting circuit. If you can find one, a clock point is excellent for this. They are designed to be connected to a lighting circuit, can be unplugged for maintenance, and they take a fuse. -- Andrew Gabriel |
How would you arrange to power a loft mounted TV aerial booster amp ? LIke I have done many times, feed from lighting circuit into FCU, amp wired directly into FCU with 3 amp fuse or smaller if poss. Only prob is if amp dies you cannot just unplug. Dave |
Aaron wrote: Pete wrote: Run it through a fused connection unit with a 5amp fuse, thus there are 2 fuses protecting the socket. yes some could uprate both fuses - but then again someone could re wire the socket completely. But will an FCU with a 5amp fuse blow as soon as 5amps of current is drawn through it? I'll bet it wouldn't, and an MCB is unlikely too until the circuit has been loaded for some time (unless you can get really quickly reacting ones). An RCD would not protect against over current here either, it'd only help if a fault were to arrise but the damage would already be done then... If they don't work then they're not even protecting the lighting circuit *before* he's added the socket. Andrew |
In article ,
"Christian McArdle" writes: If you can find one, a clock point is excellent for this. They are designed to be connected to a lighting circuit, can be unplugged for maintenance, and they take a fuse. Are these the same as BS546 round pin sockets? No, and there's no standard style for them (they aren't interchangeable between different manufacturers, and they're sold as a plug and socket matched pair). Some take the small cartridge fuse used in some shaver adaptors, and some take a regular BS1362 plugtop fuse. They were normally available in surface mount or BESA box mounting types. There's usually a screw or knurled nut to stop the plug dropping out (not that it's likely to -- this was probably to act as a bit of a "safety chain" if the clock fell off the wall). A fused 2A BS546 round pin plug/socket would be pretty equivalent. -- Andrew Gabriel |
On Wed, 01 Jun 2005 20:14:07 GMT, GymRatZ wrote:
Strangely.... When we re-wired our on-going project, there was a 2KW electric fan in the bathroom wired from the lighting circuit. My workshop dust collector doesn't have a 2kW fan ! I once lived in a flat where the (windowless) bathroom lights were fed from the shower feed. If you used the pull-cord switch to isolate the shower, all the lights went out. |
Andrew Gabriel wrote:
If it's got a flex, cut the plug off and wire it into a junction box on the lighting circuit. If you can find one, a clock point is excellent for this. They are designed to be connected to a lighting circuit, can be unplugged for maintenance, and they take a fuse. A good idea. Clock points are also good for 100V loudspeaker installations, but not everyone's house boasts a 'tannoy' system. Owain |
|
In message ,
Aaron wrote: If you were to take say 7amps on a 5amp MCB it may not trip straight away. The MCB uses an electro magnet that generates magnetic flux depending on the amount of electrons (current) flowing round the coil. As I understand it, they are designed not to trip when just over the threshold current is being drawn, because you may well get trips if say you had a fan light or tube that draws more current than usual when it starts up. From tables in the back of BS7671: 6A type B MCBs need 30A to trip in 0.4s. They need 13 or 14A to trip under 100 seconds. 9A looks like about 2,000 seconds. Less than about 8.5A is unlikely to cause it to trip at all. 1mm2 cable is rated up to 16A in normal ("clipped direct") installations, or 12A partly in insulation. A 5A BS3036 (rewireable) fuse link needs 24A to blow in 0.4s. 10A will blow it in about 100 seconds. Hwyl! M. -- Martin Angove: http://www.tridwr.demon.co.uk/ Two free issues: http://www.livtech.co.uk/ Living With Technology .... Artificial Intelligence is no match for natural stupidity |
| All times are GMT +1. The time now is 04:41 PM. |
Powered by vBulletin® Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004 - 2014 DIYbanter