balidey
|
| posted on 29/9/09 at 09:59 AM |
|
|
OT wiring into smoke alarm for plug socket?
OK, let me explain.
I need to fit a single plug socket in my back bedroom for a ceiling mounted TV, so the easiest way for me to get power to it is into the wall very
high up and go into the loft. In the loft I have very easy access to the wiring on my mains powered smoke alarms. I 'could' wire into this
and run a spur to a socket for the TV. The circuit breaker in my garage has seperate circuits for Socket, Upstairs lights, Downstairs lights and then
a seperate trip for the two smoke alarms.
Any reason (legally or sensibly) why I can't take power from these smoke alarms? There is a loop of the grey 3 core cable, so all I would need
to do is cut it, fit a juntion box and run a length of 3 core about 3m to the bedroom socket.
I would obviously label up the circuit breaker so it doesn't just say 'smoke alarms'.
If there is a good reason not to, then is it sensible or possible to take a socket for the TV off the upstairs lighting circuit?
|
|
|
|
|
YQUSTA
|
| posted on 29/9/09 at 10:21 AM |
|
|
1 very good reaason is I would guess that the smoke alarms are wired in 1/1.5mm cable which isn't rated for 13 amps. this means you cannot put a
13 amp socket on it.
what size is the breaker for the smoke alarms?
Edit: this applys to the lights too do not do it.
[Edited on 29/9/09 by YQUSTA]
|
|
|
tegwin
|
| posted on 29/9/09 at 10:24 AM |
|
|
I would not even consider doing what you suggest...
There is a reason the safety devices (fire alarms) are on their own breaker!
Depending on how your house is constructed... can you pull a spur up into the loft from the 30A ringmain?
------------------------------------------------------------------------------------------------------------------------
Would the last person who leaves the country please switch off the lights and close the door!
www.verticalhorizonsmedia.tv
|
|
|
balidey
|
| posted on 29/9/09 at 11:03 AM |
|
|
The wiring for the smoke alarms looks like its the same stuff used on the socket ring main, but without cutting it I can't be 100% sure, but it
looks really thick.
I can't easily get up from the main sockets, hence the question about using the smoke alarm wiring.
They have their own trip switch. The entire socket ring main of the house is only on one trip. I wanted to have a single socket added onto the 2 smoke
alarms circuit. It seems to me to be OK to do it. The smoke alarms beep for a couple of hours after their power supply has tripped, I guess they have
a battery backup?
Surely having mains powered smoke alarms with one additional socket on the same circuit is safer than having no smoke alarms, or smoke alarms with no
batteries in them.
|
|
|
balidey
|
| posted on 29/9/09 at 11:13 AM |
|
|
Will only be powering a 19" LCD TV, used occasionally, if that has any bearing on this. Not like its a microwave being used constantly.
The problem I have of getting a supply up from the sockets is the walls are stud partition, so even though they are hollow, I am sure there are some
horizontal beams up the wall that I will not be able to get past.
|
|
|
David Jenkins
|
| posted on 29/9/09 at 11:16 AM |
|
|
The trouble is that someone else may come along and plug a 3-bar electric fire into it, not knowing that the wiring isn't up to it.
If I was in your position I'd locate the nearest ring main and put a legitimate spur off that.
|
|
|
whitestu
|
| posted on 29/9/09 at 11:21 AM |
|
|
There's no way a single flatscreen TV is going to put 1.5mm twin and earth under any strain, though the regs would say you shouldn't do
it. A 19" TFT screen will use less than 50w. Many light fittings can take 3 x 150w traditional bulbs.
As you say the mains smoke alarms have battery backup and mains failure warning so it is highly unlikely you will encounter any problems.
I wouldn't worry about it, but take it out if you move, or take the plug off the TV and wire it into a box so anyone following you can't
plug stuff into it.
|
|
|
balidey
|
| posted on 29/9/09 at 11:22 AM |
|
|
Step 1: Wife asks for bedroom to be decorated
Step 2: Decorate bedroom
Step 3: Wife asks for new TV to be put up
Step 4: Dig channels into wall and need to redecorate the bedroom.
I think you can guess what step 5 is.... 
Oh well, I can see there is a lot of arguments against doing it, so I'll look into doing the main spur from sockets. Which was my original plan
anyway, its just when I saw in the loft there was this perfectly placed cable just begging to be used.
|
|
|
David Jenkins
|
| posted on 29/9/09 at 11:36 AM |
|
|
I wanted to put a new socket into my living room, but had no idea where the nearest ring main was...
...until my wife said "It's a shame that you can't connect to the socket in the hallway".
Doh! It was literally just the other side of a 1-concrete-block from where I wanted to put the new socket. I think I used about 200mm of cable to
connect the 2 in the end.
|
|
|
blakep82
|
| posted on 29/9/09 at 01:12 PM |
|
|
well, you sound adamant to do it, but i really wouldn't. its a safety feature, leave it as is. if the worst happens and theres a fire, if theres
any inspection to find a cause, you could land yourself in a bit of bother i'd think.
just don't do it. its propbably up to the job, but think about this, if it was ok to have other stuff on the same circuit, why did they bother
putting it on its own on?
________________________
IVA manual link http://www.businesslink.gov.uk/bdotg/action/detail?type=RESOURCES&itemId=1081997083
don't write OT on a new thread title, you're creating the topic, everything you write is very much ON topic!
|
|
|
Confused but excited.
|
| posted on 29/9/09 at 01:27 PM |
|
|
quote:
Originally posted by whitestu
There's no way a single flatscreen TV is going to put 1.5mm twin and earth under any strain, though the regs would say you shouldn't do
it. A 19" TFT screen will use less than 50w. Many light fittings can take 3 x 150w traditional bulbs.
As you say the mains smoke alarms have battery backup and mains failure warning so it is highly unlikely you will encounter any problems.
I wouldn't worry about it, but take it out if you move, or take the plug off the TV and wire it into a box so anyone following you can't
plug stuff into it.
There are several reasons why you shouldn't do it.
1) By asking the question you demonstrate a lack of sufficient knowlege.
2) A smoke alarm should NOT share a power supply with other equipment.
3) It would be illegal for you to carry out the work, unless you have it certified by a competent person upon completion. This would not happen bcause
of (2).
4) If at some point in the future there is an electrical problem or heaven forbid someone is injured/killed, you will be liable.
So regardless of the coments quoted, you should be worried. the regs are there for a reason.
Get a spark in, it shouldn't cost the earth.
[Edited on 29/9/09 by Confused but excited.]
Tell them about the bent treacle edges!
|
|
|
balidey
|
| posted on 29/9/09 at 01:50 PM |
|
|
quote:
Originally posted by Confused but excited.
quote:
There are several reasons why you shouldn't do it.
1) By asking the question you demonstrate a lack of sufficient knowlege.
2) A smoke alarm should NOT share a power supply with other equipment.
3) It would be illegal for you to carry out the work, unless you have it certified by a competent person upon completion. This would not happen bcause
of (2).
4) If at some point in the future there is an electrical problem or heaven forbid someone is injured/killed, you will be liable.
So regardless of the coments quoted, you should be worried. the regs are there for a reason.
Get a spark in, it shouldn't cost the earth.
1: Yes, well if we all knew the answers we would never ask the questions but the reason I asked was, see answer 3.
2: Who says? This was why I asked in the first place, is it legal or sensible? If you can tell me that its illegal then great. I really DO want to
know.
3: Nope, according to the government, I am allowed to add sockets to an existing circuit unless its in a kitchen or bathroom, so perfectly legal. But
I can not find any mention about smoke alarms, probably because they are not a legal requirement???
I am perfectly happy to add in a socket on a spur. But there are problems with getting to a suitable socket. So I have seen an oportunity to wire in a
socket on an underloaded trip switch. But due to not knowing 100% whether its suitable I asked the question. Yes there is a doubt in my mind, and I
really wanted a definite YES or NO, but as I have got neither then I suppose I will go back to my original Plan A and do it the hard way, the correct
way, and the way that will cause me most hassle.
But I would bet money on it that if a qualified electrician was doing the work, that he'd probably use the smoke alarm wire. Because, its only
electricity going along a cable, and if its all rated correctly, then nothing should go wrong.
But, thanks for the comments people. I'll just do it the 'hard' way
|
|
|
blakep82
|
| posted on 29/9/09 at 02:24 PM |
|
|
i was watching something on bbc 1 yesterday morning, and apparently any new building or extention (after what dates i don't know) it is a legal
requirement to have a mains wired smoke alarm
________________________
IVA manual link http://www.businesslink.gov.uk/bdotg/action/detail?type=RESOURCES&itemId=1081997083
don't write OT on a new thread title, you're creating the topic, everything you write is very much ON topic!
|
|
|
MikeRJ
|
| posted on 29/9/09 at 04:11 PM |
|
|
quote:
Originally posted by Confused but excited.
3) It would be illegal for you to carry out the work, unless you have it certified by a competent person upon completion. This would not happen bcause
of (2).
According the the regs you only need to have additional wiring in kitchens and bathrooms inspected. You are permitted to repair/maintain and add
extra power and lighting points and modify existing circuits in other rooms.
|
|
|
JoelP
|
| posted on 29/9/09 at 04:12 PM |
|
|
id stick it on the light circuit, and connect the TV via a FCU rather than a plug; but then, as a spark im allowed to do it how i like in my own house
The regs specify standard circuit layouts that, if used, allow you to skip loads of calculations. These would be the 32A ring in 2.5, or a 32A radial
in 6mm up to a certain length etc. You can however design a circuit how you like so long as it complies with all the regs.
Have a look what rating the breaker is for the lights, estimate demand at 100w per point, see what you have spare.
You do however need a tester to be sure your work is safe, which is what all DIYers lack. How could you be sure that the new point has a proper
connection to earth?
|
|
|
MikeRJ
|
| posted on 29/9/09 at 04:41 PM |
|
|
quote:
Originally posted by JoelP
How could you be sure that the new point has a proper connection to earth?
How could you be sure the old one did...
|
|
|
PaulBuz
|
| posted on 29/9/09 at 07:40 PM |
|
|
quote:
Originally posted by MikeRJ
quote:
Originally posted by JoelP
How could you be sure that the new point has a proper connection to earth?
How could you be sure the old one did...
By doing an earth loop impedance check!
Seriously though, a little knowledge can be a dangerous thing with electrics.
I am an electrician & see some frightening things on my travels.
Including work done by so called part P "electricians"!
ATB
Paul
|
|
|
JoelP
|
| posted on 29/9/09 at 08:39 PM |
|
|
quote:
Originally posted by MikeRJ
quote:
Originally posted by JoelP
How could you be sure that the new point has a proper connection to earth?
How could you be sure the old one did...
Indeed, but if you doubt the safety of the install you need it checking out anyway, whereas if the current installation is safe, you still need to
test additions anyway. 
|
|
|
whitestu
|
| posted on 30/9/09 at 07:38 AM |
|
|
quote:
I am an electrician & see some frightening things on my travels. Including work done by so called part P "electricians"!
A lot of part 'P' electricians have done a a couple of short courses but actually have very little understanding of what is safe and what
isn't. In my day it was a 5yr apprenticeship to get qualified.
I did mine in the mining industry where the consequences of getting something wrong were a bit more serious!
|
|
|
JoelP
|
| posted on 30/9/09 at 01:11 PM |
|
|
on the other hand though, domestic electrics isnt rocket science! A 5 year apprenticeship would include commercial stuff, and about 4.5 years of tool
carrying and tea making The 5 day courses were designed so that people who already undertook electrical installation could continue legally when
part P came in. Im suprised that the courses have continued for so long tbh.
and remember, to do commercial work you dont need any qualifications or registration at all!
[Edited on 30/9/09 by JoelP]
|
|
|
whitestu
|
| posted on 30/9/09 at 08:15 PM |
|
|
quote:
and about 4.5 years of tool carrying and tea making
Plenty of tool carrying, but nowhere to make tea down a coal mine!
quote:
and remember, to do commercial work you dont need any qualifications or registration at all!
You do [or did when there was one in this country] in the mining industry.
|
|
|
flak monkey
|
| posted on 30/9/09 at 08:20 PM |
|
|
On the subject of commercial stuff I found out the other day that to do gas installs commercially (in factories at least) you dont need to be corgi
registered (or whatever the new scheme is called now.
Sera
http://www.motosera.com
|
|
|
