Using a 16A appliance in a 13A socket?

[David Hansen]

On Wed, 3 Feb 2010 17:55:22 +0000 (UTC) someone who may be [e-mail] (Andrew Gabriel) wrote this:-

A point I was going to make. Emergency switching is essentially a means for unskilled persons to turn off some bit of equipment which can be stopped quickly from causing a danger, a drilling machine or lathe being an example, largely things with motors which can rip into human bodies. This might best be provided on the machine itself, at the starter rather than on some out of the way wiring point, where what is provided is a means of isolation, so that skilled persons can work on the wiring to the equipment.

In this case I understand that the kiln has a switch on it, which can be used as functional switching. If, for some reason, the kiln or the socket has burst into flames then I certainly wouldn't try to operate a switch which was beside the kiln at the socket, I value my health too much, I would be heading towards the consumer unit to switch everything off.

[Clive George]

Isn't there a point to having it remote as well, so people seeing fred being chopped up from the other side of the room can do something about it? Yes, it depends enormously on the circumstances, but I would think having a stop switch at eg near the door as well as the machine itself would be appropriate. (and of course this still doesn't apply to the kiln).

[Frank Erskine]

Does it need to be connected by plug and socket at all?

I'd be tempted to fit a metal-clad isolator adjacent to the kiln, then hard-wire the flexible cord from the kiln through a gland on the isolator.

[Tim Watts]

David Hansen wibbled on Wednesday 03 February 2010 18:43

If you can show that you took sensible measures to justify an exception, then I think you'd be on good ground:

It's a domestic premises, so shuttered sockets are normally prescribed. The exception was made on the grounds that: a) The socket is interlocked; or b) It's too high for kids to reach; or c) The workshop is dangerous anyway and is always kept locked.

c) Might be the most risky if either the person forgot to lock the shed or the house was sold and the next occupier did not use the shed as a workshop, and therefore did not keep it locked, but left the socket energised due to a lack of understanding.

However, just arguing "Your honour, I made an exception 'cos I felt like it" won't go down too well ;->

I would be very happy to do a) (in fact I plan to), then b) (I'll be doing that too because it's convenient).

[Lurch]

I've just read the whole thread looking for a slightly less newsgroupy response before I suggested ditching the plug and socket!

I'll just add the 'I agree' onto yours. ;)

[Dave Plowman (News)]

Since the plug is provided, an unswitched socket would have really no disadvantages over hard wiring - and some advantages. Even if it was rarely unplugged.

[Lurch]

Well no, but I would fit a switched one as the future usage cannot be determined, and there is a strong feeling that a interlocked socket should be used due to the shutter issue.

Unless it really needs to be truly portable, easiest, cheapest and definitely compliant method of installing the kiln is to hard wire it into an isolator on a new circuit run from the shed CU.

[NT]

Years ago we used to run 15A continuous loads on standard 13A plugs. With metal clad sockets (MK IIRC) and plugs without sleeved pins they were fine, no melting or fuse popping. But when sleeved pin MK plugs were used they melted. I'm not recommending this of course, just for curiosity.

NT

[Andy Dingley]

I've done loads of this over the years, chiefly welders, and had little trouble (but as you say, use MK kit). Until you try to unplug it, then you find the contacts are welded in place...

On the whole, I wouldn't recommend it. The worst risk is probably chronic overheating, then the insulator failing and live contacts dropping into contact with the earth. If you're not RCDing because it's a leaky or inductive load, and it's it's fused at mongo current anyway, then there's far too much risk of a firestarter arc developing and neither safety provision tripping. That's how Americans burn their workshops down.

[NT]

I was tempted to make a humorous suggestion involving a pc fan, but there's always one that might think it a smart idea.

NT

[Dave Plowman (News)]

The alternative might be to use a 15 amp three round pin plug and socket - if getting the BS4343 stuff is a problem. Present day versions are shuttered. And according to my theatre pals these sockets will stand a fair bit of overloading.

[js.b1]

Voltage drop at the shed might actually make it draw 15A anyway.

3.6kW wasn't it... if that is the 240V rating it is 15.0A so ok.

That said, c.=A320 delivered for a BS4343 Interlocked Socket isn't bad. There is no chance of any problem re interlock and proposed EV connectors using similar.

[Dave Plowman (News)]

Just thought it gets round the problem of the flex exiting horizontally.

[js.b1]

MK Commando Switch Disconnector would provide a good fixed solution. Couple of inches deep on a wall, bottom cable gland exit possible, lockable in off position, IP54 16A are cheap, easy wire(*).

(*) By "easy wire" I mean their terminals are round-hole brass like a

13A plug, rather than Rotary Disconnectors which use an inverted V cable clamp which has mandatory min cable size (otherwise the clamp is tight but your cable is loose re fire).

[Grimly Curmudgeon]

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember David Hansen saying something like:

Oh, ffs, need I spell that out?

[David Hansen]

On Fri, 05 Feb 2010 04:35:57 +0000 someone who may be Grimly Curmudgeon wrote this:-

I think so, which is why I went to the trouble of typing it out.

I have seen a number spurs which were not properly protected. Almost certainly installed by people who thought they knew what they were doing.

[rajnish1978]

I have a reverse query

Sir what will happen if a European oven with 13A main fuse rating is used in India where Standard power plugs are rated 16A after changing European plug to the Indian plug

[Brian Gaff]

Not a lot. I'm assuming the voltages and cps are the same. If its fused at 13 amp then why not. I'm assuming that you can fit normal fuses to their 16 amp plugs of course If its not fused then that really depends on the safety rules over there. Just don't call out the repair man as they might be a bit expensive! Brian

[rajnish1978]

Sir what will happen if a European oven with 13A main fuse rating is used in India where Standard power plugs are rated 16A after changing European plug to the Indian plug

[pamela]

This somehow reminds me of Prince Philip looking at a fuseboard on a factory tour and saying: "It looks as if it was put in by an Indian electrician". :)