Double sockets

[RF Lighting]

I reckon about 150W @ 50V should be somewhere near 13A.

It's a variable voltage output, which in turn also alters the current.

I can tune it in to the correct current with some CT meters.

 

[JohnW2]

Does the testing need to be carried out at 230V, or could I use say 50VAC to save my electric bill?

Why so modest? Why not go the whole hog and use a few mV - provided you can manage to get 13A through each plug/socket, that will give just as valid results

Kind Regards, John

 

[RF Lighting]

I've got a big naff off variable output ~50V transformer already which can easily deliver the sort of currents we are talking about. I just need to experiment with different wattages / resistances now to get the loading right.

I've got a fair idea of how twin sockets cope with full load on them after the weekends experiments.

I might also try a few experiments with loose connections, bolts for fuses, unfused two way blocks etc

 

[JohnW2]

I reckon about 150W @ 50V should be somewhere near 13A.

Are you sure you don't mean 3A ?

13A at 50V is obviously 650W.

Kind Regards, John

 

[RF Lighting]

Oops I meant to type 650W. Not sure where I got 150W from

 

[holmslaw]

..

 

[stillp]

Does the testing need to be carried out at 230V, or could I use say 50VAC to save my electric bill?

Sorry, BS1363 states "The tests shall be carried out at rated voltage +10%, -20%.".
I'm not sure why. If your electricity bill is a problem I'm sure we could organise a whip-round.

 

[stillp]

RF, to complicate thing further, the standard requires the use of a special test plug, which has solid brass pins (the earth not being connected). The plug is connected to 1 metre of 1.25mm sq 3-core flex.
There is also a heating resistor in the test plug that would achieve a temperature rise between the plug pins at 35 K when the load current is disconnected, i.e. during the test there is a second source of heat in addition to the voltage drop in the socket-outlet.

 

[JohnW2]

Sorry, BS1363 states "The tests shall be carried out at rated voltage +10%, -20%.".
I'm not sure why. If your electricity bill is a problem I'm sure we could organise a whip-round.

I'm not sure that RF Lighting either wants or needs to replicate all aspects of the BS1363 test, including apparently 'silly' requirements. Unless there were a massive problem of insulation resistance (which surely is tested for separately), I really cannot see why the voltage makes the slightest difference to anything, as far as the test is concerned. As for why the voltage requirement is there, I suspect that it 'sounded right' (replicating normal use) and no-one even bothered to think about any alternative - after all, in practice, the test would be done at normal mains voltage, by people not too concerned about their electricity bill, since it's the simplest and most obvious way to do it.

Kind Regards, John

 

[JohnW2]

RF, to complicate thing further, the standard requires the use of a special test plug, which has solid brass pins (the earth not being connected). The plug is connected to 1 metre of 1.25mm sq 3-core flex.
There is also a heating resistor in the test plug that would achieve a temperature rise between the plug pins at 35 K when the load current is disconnected, i.e. during the test there is a second source of heat in addition to the voltage drop in the socket-outlet.

That's very interesting. The requirement for solid brass pins might be an attempt to 'keep the plug out of the equation' in a test of the socket (which sounds fair enough), and maybe the heat source in the plug is an attempt to take some account of the effects of ageing on the plug/socket contact - albeit a seemingly rather arbitrary way of achieving that.

Kind Regards, John

 

[stillp]

John,

I suspect the use of solid brass pins in the test plug is both historic, because that's how they used to be made, and also to improve repeatability without having to specify the amount of brass in the pin, the kind of insulating material, and so on.
The heat source in the plug seems to me to represent the effect of a high resistance fuse connection; the flex is connected to the plug pins by soldering, so it might also represent the resistance of the terminals inside a standard plug.

 

[ban-all-sheds]

Yes, any voltage will do provide the current is correct. For the doubters the heat energy generated in the sockets is amps times the voltage drop in the socket between cable and plug pins.

I strongly suspect that if you increase the voltage you will eventually reach a point where heating effects are observed even with no load attached.

 

[bernardgreen]

Yes, any voltage will do provide the current is correct. For the doubters the heat energy generated in the sockets is amps times the voltage drop in the socket between cable and plug pins.

I strongly suspect that if you increase the voltage you will eventually reach a point where heating effects are observed even with no load attached.

Yes, when the leakage current through the insulation is high enough to significantly heat the material. Though at that voltage I would not like to be anywhere near the socket being tested.

 

[RF Lighting]

Im thinking that a lot of the BS1363 requirements are pretty daft and don't actually represent real world usage of these sockets, which is what we all really want to know about.

I think I'll stick with my rig. If I can i'll try and incorporate some sort of temperature probe to it.

I will continue to use real plugs with 13A fuses and shrouded pins connected to either 1.25mm² or 1.5mm² 3 core flex, as could feasibly be found in a real life situation.

I still think that a load of 26A on a double socket is hichly unlikely, espacially in a domestic property, but I'll go with it for the sake of this experiment.

I'm not sure what voltage I'll use yet. I'll have to see if I can sort out a 13A load at ~50VAC. If not I'll stick with 230V as I can easily get an exact 13A load using a dimmer to tweak things.

 

[skenk]

Will be interesting to see the results, please do post them in full. Maybe we could pitch in a pound each to pay for the power usage!?