13 Amp socket tolerances

[Pete Fraser]

I was visiting Scotland and Northern Ireland from the USA. I brought a passive power adapter, to allow me to plug my dual voltage devices into 13 Amp sockets. I found that I could plug my adapter into some sockets, but not others (even within the same house). The earth pin wouldn't go in. It wasn't clear whether it was to wide or too tall.

I just restricted myself to using the sockets where it fit, assumed I had an out of tolerance adapter, and decided to buy a better one when I got back to the states.

However, when I measured the earth pin, and compared it with the dimensions given in the Wikipedia article on BS 1363, the pin was well within tolerance.

Any suggestions? Any more appropriate forum to ask this question?

Thanks in advance

Pete

[polygonum]

Shape. Even some real plugs don't insert very well - and it always seems due to the shape of the end of the earth pin not matching well with the earth pin shutter.

A suitable level of slight wiggle and brute force usually works. But I have come across some combinations (possibly always including a poor quality socket) where the effort was not worth it and I used an alternative.

Or should that be 'ground'?

[Mike Barnes]

Pete Fraser :

My guess is it was poorly manufactured. I've been using 13A plugs and since they were invented many decades ago, and I've never had that problem. Sometimes it can be difficult to align the plug if you're coming from an awkward angle, but impossible? Never.

I suggest buying another adapter. Or, since many multi-voltage devices have detachable leads, you might buy (or borrow) a lead already fitted with a 13A plug.

[Dave Liquorice]

Aye, the earth pin should be chamfered on all four corners with the faceof the chamfer being about 2 mm wide.

Americans won't be used to shuttered sockets either and ours do sometimes take a little wiggle to get the earth pin opening the shutter.

[Pete Fraser]

I think that's probably it. I have two different adapters in front of me, and I can't remember which one I took with me. However, one has the ground pin chamfered in only one dimension, and the other has it chamfered in both dimensions. I'll make sure I take the dual chamfer with me next time.

Thanks.

[Dave Plowman (News)]

I've got one or two wall warts with plastic earth pins which are difficult to insert.

[k]

The earth pin should be longer than the others, maybe on yours it isn't ?

[Martin Crossley]

It also suggests that the adapter does not comply with British Standards and may not have a fuse.

[dennis]

Don't say that, it means a ring could be put into a dangerous state which is not prevented by the protection circuits built into the ring.

Ah well it may only burn the house down and lets face it anyone that plugs stuff into a ring that puts it into a dangerous state deserves it. But not the people that put 32A breakers into a circuit with 22A cable.

[John Rumm]

It should be about 4 x 8 mm or fractionally under - the angled bevel on the tip is also significant (should be between 58 and 62 degrees on the narrow edge, and from 60 to 80 on the wide edges), since without this it may not push the level that opens the L&N terminal shutters correctly, or jam during insertion.

It sounds like your adaptor was in some way out of spec. Generally speaking it is exceedingly rare to find a plug not fit a socket unless one is in some way damaged. The only exception to that can be some cheap multiway extension leads where the contacts are over sensitive to insertion angle, and can be tricky with some plugs. Proper wall mounted sockets however are rarely a problem.

This is probably as good a place as any...

Got any photos of your adaptor and measurements that you could post a link to?

Compare yours with this diagram from BS1363 itself:

[John Rumm]

Clueless as always dennis...

The circuit will be fine, and adequately protected. Plug fuses are there to protect the appliance flex.

An unfused adaptor could result in a flex not having adequate fault protection.

[dennis]

So what exactly stops someone plugging more than one appliance into an adapter without fuses and drawing a continuous 40 amps down an unbalanced ring or even a spur? Wishful thinking? A set of rules that the user doesn't know exists? Luck? Or maybe your old fall back.. the adapter catching fire before the cable?

Anyway I am not going to argue with you about it. You can just read my sarcastic comment.

[Bob Eager]

Exactly the same situation as someone plugging in three items on the ring, drawing roughly 13 amps each:

a) the protection for the ring (MCB/RCBO); that stops it being continuous b) the ring is tolerant of rather more than its base rating.

[John Rumm]

How about the fact that the travel adaptor only has one socket?

I don't believe it... do you have any other raison d'etre?

[Graham.]

tip is also significant (should be between 58 and 62

without this it may not push the level that opens the L&N

is exceedingly rare to find a plug not fit a socket

cheap multiway extension leads where the contacts are

wall mounted sockets however are rarely a problem.

manufacturer "MK" does not use the earth pin to open the shutter, instead using simultaneous pressure of the L&N pins to open it. Couldn't this somehow explain why the OP has success with some sockets and not others?

[John Rumm]

It may well. MK sockets are even more dependent on the pin bevel geometry being "right" to work correctly.

[ARWadsworth]

Were you born with the ability to get everything wrong or is it a skill that you were taught?

[ARWadsworth]

I think that you are picking on dennise. How the hell is she supposed to know what three times thirteen is?

[PeterC]

Have to take steps to find out.

[dennis]

Don't worry, the moron electrician can't work out that you can get 20A through one plug fuse without it blowing and 40A through a 32A breaker without it tripping. So you can overload a ring without even having to use nails or have faulty fuses or illegal adapters without fuses. All it takes is a multi way or two.

Que john to say the multi way will catch fire before the overloaded cable if the user is "lucky"!

Stick a 20A breaker in or use 4 mm2 cable and it can't be overloaded.