The thought never crossed my mind
Thanks again all.
MK triple outlet with integral 13A fuse had a melt down
- Thread starter YorkshireMidge
- Start date
Thanks again all.
You have too much on the socket and it was bound to fail. The fact that it took 10 years might be testament to using proper brand names. Cut down possible overloads and durations of such is by putting a maximum of one heavy load , in this respect we compare heating loads to non heating loads as a very simplified rule of thumb for the ordinary person.
A decent make should last forever if not overloaded much/for long duration.
Remember all sockets - single, twin,triple are rated at 13A total for the whole unit although exceeding single are type tested to a bit more abuse.
A decent make should last forever if not overloaded much/for long duration.
Remember all sockets - single, twin,triple are rated at 13A total for the whole unit although exceeding single are type tested to a bit more abuse.
- Joined
- 17 Aug 2010
- Messages
- 2,784
- Reaction score
- 462
- Country
Please point us to specific standardisation evidence for this. I believe it is simply personal opinion.
BS1363-2:
Single outlets are tested with 14 amps
Double outlets: 14 amps + 6 amps
Two or more with fuse: 14 amps
Three or more with no fuse: 2x 14 amps
Since making an unfused 3 gang would require testing with 28 amps of current shoved through it for at least 4 hours, no one bothers. Cheaper to just put a fuse in there and make it to a lower specification.
They are basically multi way extension leads without the extension part. Junk which has no purpose existing, and only made by a few manufacturers.
Single outlets are tested with 14 amps
Double outlets: 14 amps + 6 amps
Two or more with fuse: 14 amps
Three or more with no fuse: 2x 14 amps
Since making an unfused 3 gang would require testing with 28 amps of current shoved through it for at least 4 hours, no one bothers. Cheaper to just put a fuse in there and make it to a lower specification.
They are basically multi way extension leads without the extension part. Junk which has no purpose existing, and only made by a few manufacturers.
- Joined
- 17 Aug 2010
- Messages
- 2,784
- Reaction score
- 462
- Country
Yes I know that, I have the spec too. I don't see the bit where it say a double socket is rated at 13A. And some manufacturers specifically state 13A per socket for a double. The whole spec situation is a mess, but the original statement ("all sockets - single, twin,triple are rated at 13A total for the whole unit") is still a statement of opinion.
Chances are, with all those plugged in, that at some point all will it maximum load at the same instant - and well over the 13amp fuse rating. Problem is, 13amp fuses do not blow, at 13.1amps - they need a considerable overload, for an extended period of time.
All OPDs act similarly, therefore accessories should be designed to allow for that.
Ref. my original question, that all makes sense now. I'll be changing the setup as I originally felt I should.
Last edited:
Plugtop fuses have slightly worse characteristics than other OCPDs though; A plugtop fuse will hold an overload of 1.6x its rating for a minimum of 30minutes, but must clear a 1.9x overload in 30minutes. I'm pretty sure 60898 MCBs are required to disconnect a 1.45x overload in 30minutes.
The plugtop fuse is also allowed to dispate 1w, which is an awful lot when in a plastic fuse carrier in an accessory with no airflow on it tucked behind white goods which are also generating heat, and that doesn't include any extra power that might be dispated when the fuse clips get old and slightly tarnised.
Still most accessories do indeed seem to handle overloads, the only things which arn't in my experience are the fuse carriers of the accessories that have them, which is somewhat ironic. and while I've seen twin sockets burn up when carrying 2x13A of load, I would hazard a guess that this is likely not helped at all by the two 13A plug fuses dispating close to 1W each which is then conducted along the plug pins and warms the whole assembly.
Fully loaded 13A fuses seem to cause rather a lot of problems. We would be better off with 15A BS546 outlets on 20A radial circuits, unfused most of the time, but with a varient that takes a 5A fuse (they do exist and take a BS646 fuse) for things like table lamps fitted with 0.5mm flex.
Well, if you look at them they have "13A" moulded into the back of them. Ask somebody with the standards BS 1363 if it says this must be a feature in order to comply.
The standard tells us what the device is rated to.
It also tells us what it must be tested to.
Just because the twin socket is tested to 14 + 6 amps for a minimum time period etc etc does not mean it is actually rated to that.
The standard gives a minimum standard that must be achieved to comply.
There is nothing wrong if a manufacturer exceeds that minimum requirement.
If I want to run a domestic ring final circuit of 50 metres end to end length on a 32A MCB with 4.0 or 6.0 T & E cable rather than 2.5 then I exceed the minimum requirements. It does not make me "Wrong", it will almost invariably mean that it exceeds the minimum requirements and may not be the most economical use of materials (unless I had a length of 4.0 or 6.0 that I was going to throw away if not used).
If a manufacturer specifically states that their own make will be OK at 13A x 2 on their particular model then OK, fair enough but without that particular testimony we stick to the standard of 13 amps for the whole item.
Unfortunately it doesn't, or we wouldn't be having this discussion.
- Joined
- 17 Aug 2010
- Messages
- 2,784
- Reaction score
- 462
- Country
So,
a) "all sockets - single, twin,triple are rated at 13A total for the whole unit" is therefore demonstrably not true
b) "we stick to the standard of 13 amps for the whole item." No, you do.
Possibly because they are 13A sockets?
No, it doesn't.
I don't blame you for the confusion because the BS 1363 is a disaster.