BS 1363 13A Socket Continuous Max Load

There has been no change in the temperature rise test between the 1984 and 2018 versions. The rating remains 13 A. I assume that if the temperature is still rising after 8 hours, the appliance has failed the test.

There is an additional test for EV sockets which consists of 28 continuous cycles each of 8 h on, 1 h off, 8 h on, 7 h off followed by inspection.

There seems to be a fairly general acceptance these days that 13 amp plugs and sockets are not in fact suitable for a 13 amp load, other than briefly.

This is reflected in the ratings of domestic appliances on general sale. Most are restricted to about 8 or 10 amps.

3 kw space heaters are now hard to find, most are 2.2 kw or less. Tumble dryers are typically 2.4 kw at the most rather than the full 3 kw of older types.

This is said to be a policy by the makers to avoid warranty claims regarding melted plugs and damaged sockets.

The main exception is electric kettles, these are fine at a full 13 amps in practice due to the short term use. Some washing machines are also a full 13 amps, but only short term whilst heating the water, which takes only a few minutes due to the reduced water content of modern machines.

Screwfix direct used to sell and probably still sell a 3 kw fan heater, “for industrial use” and supplied without a ready fitted plug. I would think twice about use of such an appliance from a 13 amp socket. Preferring either a 15 amp round pin type or a 16 amp ceeform outlet. 

At a recent Elex “seminar” Darren Staniforth from Scolmore made a comment that BS1363 socket outlets were only tested for 8A continuous load.

If that is really what he said, and not some terrible misunderstanding, then I'm afraid he is talking ‘per-anum’  and should not be trusted on this matter.

At no point have the standard test currents been reduced.

There is a problem with 13A plugs and sockets overheating when they get old and grubby, and some minimally sized contacts in sockets do not help, but the test (which arguably is not really representative enough) has not changed in that regard.

Mike.

Would this be why 13amp sockets used for EV charging have to be marked on the faceplate as being suitable for the purpose?

I guess the difference is somewhere between a socket reaching thermal stability in the 4-8 hours, and the plastics holding all the contacts together being able to withstand that temperature indefinitely or the annealing effect of that temperature on the metals over a long time.

   - Andy.

Presumably this regulation is required because standard 13 amp sockets are only capable of supplying 8 amps for an extended period.

There cannot be any other reason, can there?

And it would perhaps make sense if in the tests for the EV marked sockets they were to be mated with EV marked plugs and run at a higher current, but they are not. The test currents are the same for normal and EV marked units - the subtle difference in testing is that the EV rated sockets also have to survive a certain number of unplug and plug in events with a load with an inductive power factor, and there is a sustained load test.

As far as I am aware, there are no design changes to an ‘EV’ marked socket, relative to the standard offerings, rather there are some extra tests, and some letters to be applied.

I cannot help feeling that it would be better if the ‘EV’ marking was duplicated  on the front, and if the extra tests did involve a higher RMS current..

Mike.

mapj1: 
I cannot help feeling that it would be better … if the extra tests did involve a higher RMS current.

Ah yes, but then they would no longer be 13 A sockets.

Interestingly, I see masterplug do a mode 2 charging socket outlet and is rated at 10A when used with a used with mode 2 charging cable. It comes with a 16A 30mA Type B RCBO. (EDIT I should  have stated type AC (RCD) RCBO)

I would have thought it would be better with a Type A RCBO rated at 10A and possibly IΔn 10mA 

Interestingly, I see masterplug do a mode 2 charging socket outlet and is rated at 10A when used with a used with mode 2 charging cable. It comes with a 16A 30mA Type B RCBO.

It's often unclear with RCBOs whether the “type” is referring to the MCB element (B, C or D) or the RCD element (AC, A, B, K, etc) - given the usual price of B-type RCDs I might suspect in this case they're referring to the MCB element type.

   - Andy.