16A socket on a radial require 20A Overcurrent device, where's the reg?

[moley]

Thanks, that makes perfect sense.

 

[Engineer54]

You will find that for 16A BSEN60309 sockets that the maximum size cable designed to fit the terminals is 2.5mm to avoid such circumstances.

Didn't realise that, ...i'll have a look tomorrow!! If that is the case, then something similar to the German DIN/VDE Schuko sockets.

Thinking about it further, surely the terminals would need to be of a size to allow 2 X 2.5mm, i've never known them to be restricted to single outlet circuits.

I know what had to be done at the Schuko sockets on one project i was on, and that was joints at the back of the deep box outlet, that joined the two circuit conductors (2 X 4mm) with a 2.5mm into the outlet terminals. That was the only solution we could come up with, the Schuko sockets were not negotiable nor was the min conductor size of 4mm for small power circuits!! lol!!

 

[Richard Burns]

I should have been clearer; the design specification for the socket gives a maximum cable size of 2.5mm.

I have just tried a 16A socket and it is possible to just about get 2x2.5 in the terminal, but it is tight ( I could not do it on the plug).
This means that you could design a circuit, in breach of the manufacturers instructions, to have a single 4mm cable but this would not allow other sockets on the radial so the current would not be exceeded.

Obviously it is possible to do as you have said above and get a radial circuit using 4mm and multiple sockets with short lengths of 2.5mm but since each item of equipment should only be 16A the cable should be OK.

 

[Tuttle]

Maybe it's to protect extension leads and/or the 16A socket? What if someone plugged in a 16A extension lead to power multiple appliances. You could get a situation similar to those old unfused 13A adapter plugs which could overload 13A sockets, on 32A ring, and start a fire.

 

[Engineer54]

When i come to think about it, it's the same situation for all European and even the Yank 16A socket outlets. ALL have restrictive cable size connections, unlike the UK's BS 1363 type 13a Fused accessories that allow 10 and in some cases 12mm of conductors to be terminated into an accessory!!


After checking this morning, it looks very much like we'll be having to joint our 4mm conductors and tail off, for our 16A socket outlets. As far as i can make out, .....so far, it's only going to really affect the maintenance and vehicle workshop areas of the project...

Thanks for bringing that to my attention Mr Burns....

 

[moley]

Thanks to everyone who's replied to my original question. Did the exam last night and the invigilator asked me which books I was allowed to use! At the time I had the regs book, OSG, GN1 and GN3 on the desk. Being a terribly honest chap I told him the truth and still managed a 92% score. Next stop NICEIC inspection, any tips?