Is it permissible to add a switch socket outlet to a radial circuit feeding an immersion. The circuit is fused at 15A, and the socket, positioned at the rear of the airing cupboard on an external wall, would be used to "plug in" an external 150W PIR light mounted on the other side of this external wall. The immersion is only used during boiler breakdowns, and I understand the fuse could trip if someone decides to make a pot of tea using the socket in the airing cupboard..
Cheers John
No, but I bet a lot of people do it. I would use a switched & fused connection unit though rather then a 13A socket.
JohnW presented the following explanation :
You could replace the flex outlet feeding the immersion heater completely with a 13amp socket outlet. If you then ever needed the immersion heater, fit a 13amp plug top to the flex, un-plug what ever is plugged into your socket (your light) and plug the immersion heater in its place.
The outlet would be more than capable of supplying anything which is normally fitted with a 13amp plug top, including a kettle or fan heater.
There is also (normally) no reason why the light could not be connected to the lighting circuit.
We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember Harry Bloomfield saying something like:
I've come across many 13A plug tops and sockets which are incapable of taking the full 3kW for long without charring.
As long as you label it at the CU, so that someone following can work out what is going on then its ok
(a kludge, but not dangerous)...
Try a decent quality one. They're usually OK.
Grimly Curmudgeon wibbled on Friday 13 November 2009 23:56
In which case they are substandard and should be replaced with a decent make. MK will handle full load fine, so will GET IME.
The only no-obvious limitation on loading is that double 13A sockets are almost all incapable of supplying 26A combined load.
True for most of them. I have a few of the older type with the full (uninsulated) pins and proper terminals that I use only for heavy loads.
PeterC wibbled on Saturday 14 November 2009 08:59
What sort of crap equipment are you people buying? I've seldom had a problem with full load on accessories, the only problems have been very old sockets where the contacts have become weak.
I've inadvetantly overloaded an extension lead here during building works but sticking about 5kW on it for 1/2 hour, until the fuse in the plug blew. The lead was pretty warm as was the plug top - but nothing was hot.
But I almost always fit MK plugs or Duraplug and MK or GET accessories.
Really - a 13A plug/socket is specifically purposed to carry 3kW for prolonged periods. If some cheap crap is unable to do that, it should be going back to trading standards.
Grimly Curmudgeon submitted this idea :
Then they are faulty, worn out, or not to design spec..
A 13amp plug or socket should be able to carry 13amps continuously and for an indefinite period of time.
We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember Harry Bloomfield saying something like:
I'll write this slowly, so you understand.
NO - it is not a good idea.
Grimly Curmudgeon wibbled on Saturday 14 November 2009 13:14
Then you cannot plug a 3kW fan into a 13A socket?
The only thing against the idea is the elevated temperature the socket will be subjected to.
But if we are arguing that a 13A socket is not designed to carry 13A continuously, then that is wrong.
We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember PeterC saying something like:
Exactly my experience. All those who advocate putting 13A through a bog standard one obviously haven't had real-world experience of fishy-smelling and charring plastic. It's also been my direct experience that even good ones sometimes fail through bad connections and overheating, given enough time carrying 13A.
To dish out such advice is irresponsible, imo.
A double socket is only rated to carry 19.5A continuously (MK). A BS1363 plug suffers from 8 watt heating of the fuse, plus a contribution from terminals & fuse tabs. Many immersions can actually drift past 3.3kW. Most sparks will fail a BS1363 plug (top) feeding an immersion.
It looks like people are suggesting fitting a plug-socket because the immersion is only used in emergency, thus unplug the light and plug in the immersion?
You could do that with a BS4343 16A IP44 plug-socket.
- BS4343 are unshuttered, so really need to be in Switch Interlocked form (plug can not be removed without power being first turned off, thus compliant with domestic requirements and avoiding flash if removed on load anyway)
- Gewiss do horizontal, vertical & compact Switch Interlocked for about =A312-14 from Discount Electrical. I have never used them or used the product, but I've kept a mental note of "compact interlocked one not a bad idea for garden extension lead if the SWA damaged again". Shipping will sting you for =A38 though - still cheaper than a Masterseal (still the best outdoor).
You can use that for DIY use upstairs since it's a dedicated radial whilst doing maintenance on other circuits avoiding running extensions down stairwells and such like, so perhaps "more justification" for the DIYer whilst legal :-)
I would not even use an MK B1363/A plug and masterseal socket for an immersion. Even 1.5mm flex gets "pretty warm" running 3kW for long which contributes to the terminal heating re wire size, contact area, fuse tab size, fuse dissipation etc. It all adds up. If you had silicone lead to the immersion and BS7211 fixed wiring supply (90oC) then "ok". Perhaps overly cautious, but immersions used in emergencies can see continuous duty and plugs are not good at 3.3kW - my own just before failure a few months later pulled 3620W on a clamp meter, they can drift. Some immersions are wired in 1.5mm which in PVC isn't going to like the terminal heating from the plug - it's lack of heatsink area. 2G has more metal to heatsink with and moves the terminals further away from the plug. Airing cupboards can get warm though (40oC
Poor quality components or poor workmanship in the wiring.
Grimly Curmudgeon laid this down on his screen :
I write this even more slowly....
A 13amp plug is rated to carry its full load load of 13amps continuously, an immersion heater is rated at 3Kw which is around
12.5amps. The idea is perfectly sound.We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember "js.b1" saying something like:
Thank you for that.
We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember "Dave Plowman (News)" saying something like:
This goes back years - I've seen chips on fire off the shoulder of O'Ryan, probably caused by overheating plugs; good makes, too.
Seriously, I wouldn't consider running a 3kW load from a 13A plug unless I was in the room - being absent (as in, it's in the airing cupboard) is just stupid.
We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember Harry Bloomfield saying something like:
I challenge you Harry. If the idea is so sound, you wire up your immersion to it and leave it wired up and switched on every time you go out.
See how long it takes before you turn into the end of your road on your return and are greeted with the sight of a fire appliance or two outside your house.
Go on... I dare you.
Grimly Curmudgeon wrote on 14/11/2009 :
Now you are being really silly. Do you have similar panic attacks about running a 3Kw electric heater from a 13amp plug and socket?
Our 3kw oven has been running on a 13amp socket for the past 15 years and our house has not caught fire yet.
Our hot water is supplied via the gas boiler, but we do have an immersion heater for back up. It's circuit has been diverted for other use and I have absolutely no intention of moving it back just to prove you wrong.
I too have seen the charred 13amp sockets and charred 100amp circuits too, but in all cases the cause was traced to poor components or poor workmanship. Use a good quality plug connected to a correctly wired good quality socket, sprinkle in some adequate workmanship and it will survive for ever supplying 13amps.
Are you suggesting you may have personal experience of charred outlets in your home?
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