Re: Internal wiring of USA v UK mains plug

[Dave Plowman (News)]

Eeyore wrote:

As late as the 1960's London had FOUR different electrical systems with
different voltages and plugs.

Are you sure about that? There were several different socket outlets still
in use - 3, 5 and 15 amp all in either two or three pin. As well as some
odd types as an alternative to the common 13 amp plug - notably D&S and
Walsall gauge, sometimes used in council housing estates. But I think the
voltage was standardised some time before then.

As late as 1989 I bought a clock radio
in London that did not have a plug on it. You had to buy one that
matched your outlets.

Yes the requirement for a fitted 13 amp plug hasn't always been.

As lightbulbs were mostly the same size around the world a friend of
mine who traveled, carried an adapator that screwed into a lamp
socket and had a standard U.S. outlet instead of the bulb.

Heh heh - in the UK the bayonet fitting is the common one for GS bulbs.

I have one that is like that but it has another lamp socket
on the top and two "euro" two pin outlets. I assume that they
are highly illegal in the U.K. now.

Perhaps the majority of the sort of things you'd want to plug in to that
are now double insulated so require no earth.

 

[Dave Plowman (News)]

I'd be very surprised about that. I can only think of 2 different plug
standards. What's your source ?

Eh? Even with final circuit rings there were at least three types of
sockets. Normal, D&S (round pins where the live was a removable fuse) and
Walsall gauge. Same as 13 amp but the pins at 90 degrees. The last two
often used by councils on housing estates. Gawd knows why. Some official
with a bee in his bonnet. Or saving pennies.

Then plenty of the old types still in use. 3,5 and 15 amp round pin. In
both 2 and three pin. Then there were some oddities with flat pins.

US visitors used to laugh at our variety of sockets, domestically. Now we
have only one, and they have the variety...

 

[Eeyore]

Are you sure about that? There were several different socket outlets still
in use - 3, 5 and 15 amp all in either two or three pin.

2, 5 and 15A and they were all part of a single standard. Only the 2 and 5A
existed as 2 pin types.

http://en.wikipedia.org/wiki/BS_546

Graham

 

[Eeyore]

Eh? Even with final circuit rings there were at least three types of
sockets. Normal, D&S (round pins where the live was a removable fuse) and
Walsall gauge. Same as 13 amp but the pins at 90 degrees. The last two
often used by councils on housing estates. Gawd knows why. Some official
with a bee in his bonnet. Or saving pennies.

Then plenty of the old types still in use. 3,5 and 15 amp round pin. In
both 2 and three pin. Then there were some oddities with flat pins.

The 2 and 3 pin 2, 5 and 15A plugs were all part of a single standard.
http://en.wikipedia.org/wiki/BS_546

Never seen any flat pin jobbies.

As for Walsall gauge I've only ever seen that in the tube. Did councils really
fit them ?

Graham

 

[[email protected]]

No, he IS saying it is in use. Some of it has been replaced, but not
all of it.

Exactly that. The precise term is "Knob and Tube", The insulation is
a mixture of silk, rubber and asphaltic tar that remains quite stable
under most conditions, although it becomes brittle at temperature
extremes (hot and cold). One would think from the ingredients that the
insulation would burn from a sideways glance... not so at all.

I worked my way through college as an old-house electrician and ran
across scads of the stuff. Some of the original lighting circuits (but
nothing else) in our house are still operating from K&T wiring
installed in 1906. The house was built in 1890, originally piped with
gas for lighting.

http://images.google.com/images?hl=en&q=knob+and+tube+wiring&gbv=2

Will show you it in-situ.

If you keep in mind that the conductors are typically separated by
some distance, and where they penetrate boxes, walls and turn
corners, there is either a ceramic insulator (knob) or ceramic/
additional woven silk/asphalt/rubber (tube), as long as the copper
itself is not raised to ignition-point temperatures it is quite safe.

With reference to the NEC, it may be maintained but not installed-as-
new.

And an unbelievable amount of flea-market wind-chimes are made from
old ceramic tubes....

Peter Wieck
Wyncote, PA

 

[Dave Plowman (News)]

2, 5 and 15A and they were all part of a single standard. Only the 2 and
5A existed as 2 pin types.

Not so. My parent's house had 2 pin 15 amp sockets - one in each room, as
installed when the house was built.

 

[Dave Plowman (News)]

The 2 and 3 pin 2, 5 and 15A plugs were all part of a single standard.
http://en.wikipedia.org/wiki/BS_546

I'm just guessing but I'd say the BS that applies to them now didn't when
they were first introduced.

 

[David Starr]

Ok, I'll conceed that one, but only 50%, after all, how many people
put a 16amp fuse on a .5mm cord?

A lot. Trust me on this.

David Starr

 

[[email protected]]

[email protected] wrote:

The current EU standard is a 2 pin plug that looks like the one you have
not seen in 20 years.

This is only confusing things. There are other types as well, but the
ones that dont fit UK sockets are todays EU ones. The old ones I refer
to are not the old british 2 pin plugs from the 1920s, but the old
french ones that were still in use in many places in fr in the 80s.

The grounded version is the same with a third
pin of the same diameter, but slightly longer between them but below.

The two "fat" round pins, were only used in some parts of Europe and
does not fit in the U.K. outlets.

There's more than one type answering that description, so its hard to
know what you mean.

According to an answer to a previous post, modern U.K. outlets have
shutters which are opened by inserting the ground pin. This is to
prevent the two round pin plugs going in on their own, albeit with
a little force.

Most work that way. There are also some with a shutter operated by the
L&N pins. These are harder to defeat. Not sure but I think MK
introduced those.

The main purpose of the shutter is to stop toddlers poking things in.
They also discourage people from sticking bare wires in, followed by a
plug on top. This bad practice is a lot less common today as it doesnt
usually work with insulated pins, plus ever increasing material wealth
makes it a pretty much obsolete practice even in dodgy circles.


NT

 

[[email protected]]

On Jun 28, 2:09 pm, [email protected] (Geoffrey S. Mendelson) wrote:

Exactly that. The precise term is "Knob and Tube", The insulation is
a mixture of silk, rubber and asphaltic tar that remains quite stable
under most conditions, although it becomes brittle at temperature
extremes (hot and cold). One would think from the ingredients that the
insulation would burn from a sideways glance... not so at all.

I worked my way through college as an old-house electrician and ran
across scads of the stuff. Some of the original lighting circuits (but
nothing else) in our house are still operating from K&T wiring
installed in 1906. The house was built in 1890, originally piped with
gas for lighting.

http://images.google.com/images?hl=en&q=knob+and+tube+wiring&gbv=2

Will show you it in-situ.

If you keep in mind that the conductors are typically separated by
some distance, and where they penetrate boxes, walls and turn
corners, there is either a ceramic insulator (knob) or ceramic/
additional woven silk/asphalt/rubber (tube), as long as the copper
itself is not raised to ignition-point temperatures it is quite safe.

With reference to the NEC, it may be maintained but not installed-as-
new.

And an unbelievable amount of flea-market wind-chimes are made from
old ceramic tubes....

Peter Wieck
Wyncote, PA

Seems the US developed a long lasting wiring system long before we
did. It wasnt until ashathene and pvc cables in the 60s that we
finally got cables of types that would truly last long term. So old
wiring here is almost invariably highly risky, in a very bad way and
only very occasionally encountered at all.

The main old types here are
- cotton/rubber, and its normal for the insulation to have perished
and fallen off in places, and not just at the ends.
- lead sheathed rubber insulated from 1930s, the ends of which get
into a state.


NT

 

[Eeyore]

Not so. My parent's house had 2 pin 15 amp sockets - one in each room, as
installed when the house was built.

When was this built ?

Graham

 

[Eeyore]

A lot. Trust me on this.

Since a 16A fuse for a UK plug doesn't even exist, I'll take your " Trust me on
this." with a pinch of salt.

Graham

 

[Eeyore]

This is only confusing things. There are other types as well, but the
ones that dont fit UK sockets are todays EU ones.

There is no such thing as an *EU* plug.

Thankfully it's one thing they haven't tried to standardise.

Graham

 

[Joel Kolstad]

There is no such thing as an *EU* plug.
Thankfully it's one thing they haven't tried to standardise.

Just wait, I'm sure they'll get around to it sooner or later...

 

[[email protected]]

That is a sociologic/economic. not technical issue.

I dont see how. Cooking fire risks certainly differ by socio-economic
group, but I dont think electrical fire risks vary much. Things are
perhaps different in the US.

I don't know what your load is. The US load per branch circuit is 1800 W,
before the circuit breaker in the box will trip. I think a GFI will trip at
10 microamps.

20mA is the typical figure for our standard 30mA RCDs, but most fire
causing faults are not detected by RCD, and most properties dont have
an RCD.

But that is a separate issue to fault current discriminaiton.


NT

 

[[email protected]]

Seems the US developed a long lasting wiring system long before we
did. It wasnt until ashathene and pvc cables in the 60s that we
finally got cables of types that would truly last long term. So old
wiring here is almost invariably highly risky, in a very bad way and
only very occasionally encountered at all.

The main old types here are
- cotton/rubber, and its normal for the insulation to have perished
and fallen off in places, and not just at the ends.
- lead sheathed rubber insulated from 1930s, the ends of which get
into a state.

That is just the half-of-it. We have had NEMA (National Electrical
Manufacturers Association) standards for pretty much all of present
living memory such that appliances (AC & AC/DC) manufactured in the
20s are compatible with receptacles and ratings today. For instance,
1920s-installed duplex receptacles will accept fat-blade neutral
(polarized) plugs that are today's standard. One can 'call out' by
NEMA number a receptacle and plug that are specific to, and compatible
with both the load and application, from isolated-ground hospital-
applications to heavy-load vibration-proof applications, one, two
(yes, there is still 4-wire/2-phase power applications in the US) and
three-phase. And, be assured that that unit and/or combination will
fit and be acceptable anywhere in the US. One example I claim is a
1928-model Sky Rover radio with a tri-voltage switchable power-supply
(105/110/120V) and a standard NEMA-labeled plug. About a year-and-some
after NEMA's inception.

http://www.nema.org/about/history/

On a related note, IMAGINE purchasing an appliance with no plug on
it... on the premise that what is in your house is not the same as
next door, or next door to that. AND THEN... the home-owner is
expected to purchase said plug compatible with their specific system,
THEN to install it correctly. This was the common state of affairs in
parts of Europe until not so long ago.

Fascinating also that every country in Europe seems to have a
different standard for receptacles, wiring, fusing and so forth. Y'all
do need standards if only to allow cross-border commerce much less
reduce costs and enhance safety.

Peter Wieck
Wyncote, PA

 

[DJ Delorie]

On a related note, IMAGINE purchasing an appliance with no plug on
it... on the premise that what is in your house is not the same as
next door, or next door to that. AND THEN... the home-owner is
expected to purchase said plug compatible with their specific system,
THEN to install it correctly. This was the common state of affairs in
parts of Europe until not so long ago.

Actually, this is common in USA woodworking equipment also. Many of
my 240V machines came with no plug.

 

[[email protected]]

Actually, this is common in USA woodworking equipment also. Many of
my 240V machines came with no plug.

With no plug, or no cord at all? Those are two entirely different
things. The former is illegal, the latter quite common. With the
latter, there will be a note: Professional Installation Only or words
to that effect.

Peter Wieck
Wyncote, PA

 

[DJ Delorie]

With no plug, or no cord at all? Those are two entirely different
things. The former is illegal, the latter quite common. With the
latter, there will be a note: Professional Installation Only or words
to that effect.

I've seen both "cord with no plug" and "no cord at all". The reason
is usually that the tool can be internally wired for either 120v or
240v, and which you choose determines which plug you must install.

I'm not talking about hand tools, I'm talking about big cast iron
tools like table saws and jointers.

 

[[email protected]]

The USA cannot have the equivalent of RoSPA (Royal Society for the
Prevention of Accidents)

We have the NEC, ANSI (and NFPA) and NEMA. That is:

National Electrical Code

American National Standards Institute

National Fire Protection Association

National Electrical Standards Association

They all have jurisdiction over the way things-electrical are
represented, sold, wired and fused. We have a National testing
organization - Underwriter's Laboratory, AKA UL that puts labels on
entire assemblies (UL) or parts that go into them (UR), and works
closely with Canada in the same way with similar alphabet soup.

Our receptacles have very narrow slots with the conductors held back
from the front. Not at all to say that accidents don't happen, but it
is not so easy as with the honking-large slots on Brit receptacles so,
putting little shutters on them is a good idea.

Peter Wieck
Wyncote, PA