"idiot proof" final circuit design

[dennis]

It would be fine if the first thing you did was to weld the plug pins to the socket. 8-¦

Its probably easier to fit a bigger connector.

[John Rumm]

No, the plug itself is only rated for 13A. As is the socket.

On a practical level you would be hard pushed to terminate 4mm^2 wires in an ordinary plug, let alone get the cord grip on.

[Owain]

Because you can put three 10A appliances on one 32A ring in *any* socket combination. You can only put one on each 16A radial, so two radials will only feed two such appliances, *one on each radial*. If you try plugging both into the same radial you will overload the circuit. Hence you have the stupid situation of having to think "I can't plug this in here but I can plug it in over there".

Owain

[Owain]

No of course it wouldn't and you know it; it is presenting an unacceptable point load. Ring circuits are *designed* around certain parameters all of which work *together*

Owain

[Dave Plowman (News)]

According to a Dutch pal this is the case there. Dunno about the US.

[DJC]

Yes, and if I want a double socket for my kettle and toaster it would require two radials to the same location. At which point all the wiring for a ring is in place.

[Jim Michaels]

So two 3kW kettles in a double socket is not acceptable?

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[Jim Michaels]

And nobody sees a problem with 13a sockets on a 32amp circuit?

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[Andy Hall]

No, because they are engineered to way above 13A in terms of the contacts. The 13A refers to the maximum current taken through a plug via the fuse.

They are of a substantially higher quality as well - $10 and up being typical rather than 99c.

[Owain]

It's not desirable, but in a domestic environment (and I've lived in shared houses with two kettles, to cater for the home-from-work tea stampede) they're only going to be used occasionally.

In a commercial kitchen (which could include a house doing B&B) more appropriate provision should be made. Ring circuits should only be installed where they are *suitable for the load*.

Owain

[Owain]

No more than a 100A service fuse on a ????A ring main off a substation.

Owain

[Andrew Gabriel]

People don't generally have two kettles in the same place, but it would be no problem given a 3kW kettle can't be on for long anyway.

[Andrew Gabriel]

No, they're fused at 13A max.

I don't have a copy of BS1363, but I think manufacturers are required to show their 13A plugs and sockets will run at 26A for a hour without any problems, and are then required to overload test them to destruction, and to show they don't fail in grossly unsafe ways. The test requirements for BS1363 products are one of the most onerous of any test procedure.

[John Rumm]

No. They are fused at (a maximum) of 13A anyway.

[John Rumm]

It is not ideal, but in a domestic situation you can generally ignore such loads in your diversity calculations since they are such short duration.

[Tony Bryer]

When you look at American or Australian plugs with a fraction of the metal in the pins I wouldn't expect any.

[Dave Plowman (News)]

In practice few sockets round the house are likely to be loaded to anything near this, since heavy *continuous* loads like heating ain't normally done off the ring main. The likely sockets which will have this sort of loading - but not *continuous* - are in the kitchen, where there will usually be a separate ring. And the wiring for the average ring is capable of carrying more than 32 amps anyway.

[Dave Plowman (News)]

Yup. Commercial installations where continuous loads can be accurately calculated are likely to use radial circuits - even if fitted with 13 amp outlets.

If you intended heating every room in a house with a fan heater etc on all the time to give 'central' heating, a ring wouldn't be appropriate.

Load diversity is the key, and it's applied to things normally fed via a radial in the home like cookers and hobs too.

[Jim Michaels]

As I said in the thread a few hours ago,

Either the socket is adequate for the 32amp circuit it is on or it isn't. Relying on whatever is plugged into it to not draw too much is far from idiot proof, it isn't even non expert proof.

Anyone want to buy non-fused BS1363 style plugs?

is a big world and I am sure this is not the only vendor.

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[Dave Plowman (News)]

Are you trying to say that all sockets on radials are capable of carrying the full rating of that radial as a continuous load? Because this doesn't seem to be the case in most counties.

They've got nothing to do with BS1363, and have no type approval anywhere.