Confused again? It must have been a good bottle!DS
I was merely stating facts about the current Technical Data Sheet for MK double sockets.
Kind Regards, John
Changing plug socket. Earth question
- Thread starter Alex evans
- Start date
I was merely stating facts about the current Technical Data Sheet for MK double sockets.
Kind Regards, John
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Bottom line
13 amp plug is a style of plug and should not be taken as a current rating for all plugs that are made in that style.
Hence a dual socket that can take two plugs of that style does not have to be able to carry 2 times 13 amps.
Not all 13 amp style plugs are rated at 13 amps. Many are not capable of safely carrying 13 amps.
The GPO in the 1960's or 70's derated all 13 amp plugs in Post Office use to a maximum of 9 amps. One brand was allowed to be used at 13 amps but still required authorisation for that use. As it happens it was MK plugs that could be used for loads greater than 9 amps.
13 amp plug is a style of plug and should not be taken as a current rating for all plugs that are made in that style.
Hence a dual socket that can take two plugs of that style does not have to be able to carry 2 times 13 amps.
Not all 13 amp style plugs are rated at 13 amps. Many are not capable of safely carrying 13 amps.
The GPO in the 1960's or 70's derated all 13 amp plugs in Post Office use to a maximum of 9 amps. One brand was allowed to be used at 13 amps but still required authorisation for that use. As it happens it was MK plugs that could be used for loads greater than 9 amps.
DS .
There is no current rating system for 13A s/o, the only guide is the temperature rise test in BS 1363. The basic test parameters are:
1 x 13A s/o test current 14A.
2 x 13A s/o test current 14A + 6A = 20A
>1 x fused 13A s/o test current 14A
>2 x unfused 13A s/o test current 14A +14A = 28A
1 x 13A s/o test current 14A.
2 x 13A s/o test current 14A + 6A = 20A
>1 x fused 13A s/o test current 14A
>2 x unfused 13A s/o test current 14A +14A = 28A
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I am pretty sure that I have never seen one which does not have 13A written/embossed on it - and I can but imagine that refers to a 'rating', not a style - just as it would on any other electrical equipment.
Can you give an example of a make of (a legitimate!) BS1363 plug that is not 'rated' at 13A ?
Kind Regards, John
Then there really is no limit to the stupidity of our trade.
Sorry for being un-clear. Rated at 13 amps but fail at lower currents.
That's just a sub-standard product, then - such as exist in all walks of life.
Kind Regards, John
When you add time to the equation the product is not substandard until after the current has been passing for some time.
Test at 13 amps for 1 minute, it passes, Test at 13 amps for 10 minutes and it might fail on temperature rise, Test at 13 amps for a day and it might fail by melting
I feel sure that the law, and the Standard, would require a 13A-rate plug to be able to safely carry 13A for an 'appreciable' period of time - certainly more than 10 minutes, probably more than an hour - and would regard it as 'substandard' if it were not capable of that.
In fact, in most situations/environments, I would have expected a thermal equilibrium to be achieved fairly quickly - so I would not really expect the temperature to be higher after a month than after an hour or two.
In fact, on reflection, I think it might be quite difficult to design a "13A" plug (of the usual sort of design) that could not carry 13A more-or-less indefinitely, even if one wanted to - the spring clips for the fuse are the only element where I could see some scope for a problem. I would think that most of the temperature rise associated with a plug/socket combination would be done to the socket, wouldn't it?
Kind Regards, John
I've seen some in which the use of unsuitable plastic material allowed the moulding to soften around the pins, to the extent that when the plug was removed, the live pin remained in the socket!
Ah - maybe that's the way to make one that can't safely carry 13A for an 'appreciable' period of time, then! I confess that I hadn't thought about what plastic material might be used but, apart from that, and the fuse clips I mentioned before, I still can't think of any other way of making one that couldn't carry 13A for a good while!
Kind Regards, John
we do a lot of commercial kitchens and often find two high current appliances in a twin socket, both mk and cheapo.
Either on a ring or on 6mm radials.
I do not recall ever one socket failing or even look like its failing.
However, we find the moulded plugs melted, individual socket switch failed or burning up of a pin usually the neutral.
If the internal brass links across the sockets are the eguivalent of 4mm copper i cant see how it can be a problem
Either on a ring or on 6mm radials.
I do not recall ever one socket failing or even look like its failing.
However, we find the moulded plugs melted, individual socket switch failed or burning up of a pin usually the neutral.
If the internal brass links across the sockets are the eguivalent of 4mm copper i cant see how it can be a problem
This might be a good time to remind readers about http://www.bs1363.org.uk/
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