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
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 more appropriate forum to ask this question?
Thanks in advance
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
Or should that be 'ground'?
On Tue, 30 Aug 2011 07:27:16 +0100, polygonum wrote:
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
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
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.
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
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
On Tue, 30 Aug 2011 22:25:04 +0100, dennis@home wrote:
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.
Use the BIG mirror service in the UK:
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.
Not entirely sure why dennis is prattling his usual tripe about ring
circuits when the question is about travel adaptors - fused or otherwise.
Well lets say the multiway survives the sustained 20A load (the better
ones might), and someone fairly clueless manages to cobble together 10kW
of load all in one room at one time, and connect it into a pair of 4 way
trailing leads. Then they plug them both into a double socket...
(obviously this is only ever likely to happen in dennis's house - but
dear reader, for the moment, pretend its somewhere in the real world).
We will skip over the fact that there is not a double socket out there
that will take 40A for long before it becomes bleeding obvious to all
that something is not happy, and assume perhaps our dimwit has used a
pair of sockets on the same circuit, and look at what will happen to the
Bugger all really. If the sockets are right at one end of the ring close
to the CU (which obviously they won't be because unlike dennis,
competent electricians think about things like this, and use appropriate
topologies for the circumstances), one cable may get a tad hotter than
it ought. If kept that way it will probably shorten the life of the
cable. The more likely outcome is nothing exciting will happen.
Obviously that worries dennis, he would rather it all burst into flames
for some reason...
(no doubt the millions of homes that have not spontaneously combusted
due to non dennis circuit designs being employed, will in no way dent
his belief since these numbers are obviously statistically not relevant)
 Obviously keeping that 10kW of load sustained is actually quite a
challenge, but I am sure dennis can think of a way.
That would be a woosh...
Still apparently dennis is not going to argue with me any more (unless
he was telling porkies yet again!) so we can enjoy the silence...
snip same old.
Still arguing that the rules keep it safe, even though the users don't even
know what the rules are.
Still argues that the iee know best, even though they are constantly
changing the rules as they cover up previous mistakes.. like only fitting
one socket to a 2.5 mm spur when they used to allow two. Shame about the
millions already out there.
Still argues that overload protection can be left to a user supplied device,
one the user knows nothing about or what it does or what happens if its done
Still calls anyone with contrary views about safety wrong even when the
recommendations are safer and don't rely on the user knowing the rules, or
supplying safety devices.
You really don't have an argument, you just be a good boy and do the minimum
the "regs" say, I will just exceed them as usual.
Ah, apparently he was fibbing again... really dennis!
Where does anything I said require user knowledge of rules?
Know best? possibly. Know better than you, I believe so.
I don't recall multiple sockets ever being allowed on an unfused spur.
Perhaps you could say when you believe this was the case?
However as a more general point, I actually find it reassuring that the
wiring regs change and evolve. It demonstrates good engineering that
research is still being done, empirical data are being collected, and
the guidance being revised or improved in the light of this. Patterns of
use change, and technology advances. It is right and proper that the
guidance moves on to accommodate these changes.
I don't believe I did argue that. In fact I think I explicitly said that
the plug fuses were there for fault protection of the appliance flex,
not overload protection.
Well if you make clearly erroneous and misleading statements about the
absence of a plug fuse resulting in:
"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."
That is not a "contrary view", its simply nonsense.
The daft thing is that your idea of "exceeding" the regs comes down to
reducing the functionality and flexibility of standard circuits, while
increasing their expense and time to install, and yet yielding no
demonstrable improvement in safety.
As with most efforts to "over engineer" a solution, it demonstrates a
lack of any real engineering finesse.
Well both really. Any fool can keep nailing 4x2"s on until it stands up.
It takes and engineer to do it with the minimum of materials, and cost,
and still get it to stand up and meet all the customers requirements.
Hmm, it was an engineer that made the walls too weak on the Comet.
It was an engineer that design Chernobyl
It was an engineer that put the cooling plant for Japans reactors too low
It an engineer that thinks 32 Amp breakers are OK for 22 Amp cable.
To justify this he states:
well the user will never have enough appliances to overload it.. oops wrong.
you can stop overloads because there is a 13A fuse in the plug which blows
at 20A.. oops you can get faulty and/or fake ones that don't.
the user will never do anything stupid to the plug.. well we all know how
stupid that idea is.
need anyone go on?
Just design the damn circuits so they are properly protected at the consumer
unit without the user having to provide additional protection. Anything that
requires user cooperation is inherently less safe.
Even the IET can manage it as can be seen with the modern radials they want
electricians to use. You know the ones that actually specify a breaker that
protects the cable even if the user puts a nail in place of the plug fuse.
Ah, the days before ring mains when we had 5A 10A and 15A sockets, all
radially wired with their own (wire) fuses. What a waste of cable when
most folk had only one electric fire of one or possibly two Kw, possibly
a 1Kw electric kettle and the rest were standard or table lamps (not
many of them either) and a wireless.
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