Internal wiring of USA v UK mains plug

[Dave Plowman (News)]

Mid '30s - and 240v AC from the start.

 

[Dave Plowman (News)]

Not really. Domestically, for GP recepticals, there is only the the one
basic standard with a few minor variation, all backwards compatible to
the parallel blade two prong plug.

I can see that a modern three pin socket might accept older plugs, but the
other way round?

 

[Dave Plowman (News)]

Technically likely not. But there is a two round pin plug that will fit
into most of Europe's sockets, and the CEE7/7 (AKA Shucko) which will
fit into a subset of those.

There is a plug which will 'fit' but isn't up to the maximum rating of
those outlets. So really of little use.

 

[Gary Tait]

I can see that a modern three pin socket might accept older plugs, but
the other way round?

Nope, not without an adapter, which is considered by professinals
potentially unsafe, and are often used in an unsafe fashion.

I stand by the context of my original text, the lowest denominator is
the two prong parallel plug, which will fit into nearly all domestic
sockets since the 1930s. Before that the recepticals were unpolarised,
although it took until the 1970s for polarised two prong plugs to be
required on lamps and TV sets, and later some other appliances.

So, an appliance with a basic two prong plug, will fit into a two prong
receptical, a U-Grounded 3 prong vertical slot 15A receptical, and the
"T" slot 20A general purpose receptical. An unpolarised appliance with
also connect to a pre 1930s unpolarised receptical or light socket
adapter or a 10-15 receptical (whose slots were designed to accept both
angled and vertical prongs).

 

[John Larkin]

I can see that a modern three pin socket might accept older plugs, but the
other way round?

Grab the ground pin with some pliers and twist it off.

John

 

[James Sweet]

Helps ?
It must be easier learning Japanese than learning to differentiate all
that
lot and then ominously on top of that sections marked "Reserved for Future
Configurations"
Is it subsets of that lot for each state or each utility company or a
total
mish-mash ?

There's about 3 different types of receptacles you'll find in a US
residence, the rest on that list are either industrial stuff or obsolete
things you might find in the occasional 1950s or earlier house. Generally
you'll find mostly 15A 120V grounded types, then the clothes dryer will have
a 30A 240V receptacle and the kitchen stove will have a 50A 240V receptacle.
Other high powered items like an electric furnace, water heater, spa, etc
will be hard wired. Sometimes you'll find a 15 or 20A 240V receptacle in the
garage for something like an air compressor or small arc welder but these
are generally added by the homeowner. It's really not very complicated.

I know the UK has a number of plugs and receptacles in the same category,
I've got a small pile of various oddballs from over there right here.

 

[James Sweet]

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.




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.

GFCIs have been mandatory here for decades on any receptacle located
outdoors or within a certain distance of water, such as in kitchens and
bathrooms. Modern code is now requiring arc fault interruptors in bedrooms,
and eventually everywhere.

 

[Dave Plowman (News)]

There's about 3 different types of receptacles you'll find in a US
residence, the rest on that list are either industrial stuff or obsolete
things you might find in the occasional 1950s or earlier house.
Generally you'll find mostly 15A 120V grounded types, then the clothes
dryer will have a 30A 240V receptacle and the kitchen stove will have a
50A 240V receptacle. Other high powered items like an electric furnace,
water heater, spa, etc will be hard wired. Sometimes you'll find a 15
or 20A 240V receptacle in the garage for something like an air
compressor or small arc welder but these are generally added by the
homeowner. It's really not very complicated.

I know the UK has a number of plugs and receptacles in the same
category, I've got a small pile of various oddballs from over there
right here.

Not really. In a domestic environment anything that can't be plugged into
a 13 amp outlet will be hard wired. Including cookers, water heaters,
showers, etc. A very posh home workshop may use BS 4343 industrial types
though as some machine tools on single phase may need more than 13 amps.
Three phase domestic supplies are pretty unusual.

 

[James Sweet]

Not really. In a domestic environment anything that can't be plugged into
a 13 amp outlet will be hard wired. Including cookers, water heaters,
showers, etc. A very posh home workshop may use BS 4343 industrial types
though as some machine tools on single phase may need more than 13 amps.
Three phase domestic supplies are pretty unusual.

Well that's not much different than here, only difference I see is that we
have 30 and 50A 240V plugs to allow cook stoves and clothes dryers to be
high power yet not hard wired. Standard clothes dryer here is 4KW, kitchen
range is 12KW. I had a Creda dryer for a while from the UK, it was a nice
unit, but tiny and took forever to dry.

Looking through the box here... There's an IP44 plug, not even sure what
it's for, but I've never seen anything like it, looks very heavy duty, a
round pin 2 amp plug that says it's for table lamps which oddly enough has
three prongs just like the big clunky plugs, got a few of those, hmm, could
swear I had another type as well.

I like the quality of the parts overall, but these junction boxes are
*teeny*, it must be a real pain to wire them. I like the BC light sockets as
well, though they don't hold large heavy bulbs very straight.

 

[Wolfi]

Am 29.06.07 11.50 schrieb Eeyore:

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

Sure it is!

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

Here you are wrong.
The Euro plug is a flat, 2 prong, 4mm round contact plug, with pins 17mm
apart, fitting into regular 16A/240V outlets, but meant only for low power
devices. Its current rating usually is only 2,5A and they are widely used for
connecting consumer electronics (where the other end of the cable often is
pluggable too, having the 8-shape socket, if you look at it, with 2 small
receptacles 10 mm apart), small AC/DC power supplies, 240V to 2...24V
transformers and such.

They fit into the round 5mm receptacles of German type 3 contact "Schuko"
sockets, where the plug body actually dives into the outlet cover by some
20mm, allowing it to take on mechanical forces applied to the cable, rather
than having the contacts themselves deal with it.

The lack of appropriate machanical stress handling is my biggest rejection of
the American type 130V power plug system, in addition to extremely poor design
of those flat contact receptacles, which wear out very easily, giving poor
contact with all bad things to follow..

 

[Wolfi]

Am 29.06.07 17.59 schrieb Gary Tait:

Technically likely not. But there is a two round pin plug that will fit
into most of Europe's sockets, and the CEE7/7 (AKA Shucko) which will fit
into a subset of those.

It is "SchuKo", from german "SchutzKontakt", meaning protective aka grounded
contact, which are the 2 grooved in metal stripes at the top and bottom of the
plug housing.

 

[Wolfi]

Am 29.06.07 18.41 schrieb Dave Plowman (News):

There is a plug which will 'fit' but isn't up to the maximum rating of
those outlets. So really of little use.

Just the opposite.
The Euro plug is not designed that you can travel across Europe with your
3680W water boiler and plug it in everywhere, but for all those <= 575W
gadgets, people like to have with them, while they are travelling, but also
for devices being fully insolated, hence mot requiring the protective ground
like VCR, TV, RCR, audio amplifiers, satellite receivers, battery chargers,
etc, etc.

The Schuko outlet is rated for 230V AC to up to 20A, even though in most cases
16A breakers are used since some 3 decades.

This system is also common in Austria, Switzerland, former Yugoslavia and
Greece. I'm not sure about the Cech and Slovak Repuplic.

 

[John Larkin]

The lack of appropriate machanical stress handling is my biggest rejection of
the American type 130V power plug system, in addition to extremely poor design
of those flat contact receptacles, which wear out very easily, giving poor
contact with all bad things to follow..

Not in my experience. I've owned houses that were first wired in the
early 1900's, and I don't recall ever having a bad wall outlet. Most
of the really old ones have been replaced, not because they failed but
rather because they had to be upgraded to accept a 3-prong plug.

A decent 3-prong molded plug, plugged into even a cheap (79 cent) dual
wall outlet, seems to be perfectly reliable. Our biggest problem is
cats chewing on the cords, some of which seem to be tastier than
others.

John

 

[jakdedert]

Not in my experience. I've owned houses that were first wired in the
early 1900's, and I don't recall ever having a bad wall outlet. Most
of the really old ones have been replaced, not because they failed but
rather because they had to be upgraded to accept a 3-prong plug.

A decent 3-prong molded plug, plugged into even a cheap (79 cent) dual
wall outlet, seems to be perfectly reliable. Our biggest problem is
cats chewing on the cords, some of which seem to be tastier than
others.

John

I've replaced a number of two prong outlets in my house (vintage 1928)
because the outlets failed in just the manner described. I don't know
the actual vintage of the particular sockets involved--although it's
pertinent that no two were the same, leading me to believe that they
themselves were later replacements for the originals.

In some cases it was possible to easily rewired with grounded 12/2 romex
from the breaker box. In others, where that was not practical, the
two-prongers were replaced with new outlets--also two prong.

These are still available and should be used if upgrading to a properly
grounded outlet is not done.

In any case, IME the OP's statement is entirely accurate. The
edison-style outlets are either inherently--or at least 'as
implemented'--prone to losing secure contact.

jak

jak

 

[Eeyore]

There's about 3 different types of receptacles you'll find in a US
residence, the rest on that list are either industrial stuff or obsolete
things you might find in the occasional 1950s or earlier house. Generally
you'll find mostly 15A 120V grounded types, then the clothes dryer will have
a 30A 240V receptacle and the kitchen stove will have a 50A 240V receptacle.
Other high powered items like an electric furnace, water heater, spa, etc
will be hard wired. Sometimes you'll find a 15 or 20A 240V receptacle in the
garage for something like an air compressor or small arc welder but these
are generally added by the homeowner. It's really not very complicated.

I know the UK has a number of plugs and receptacles in the same category,
I've got a small pile of various oddballs from over there right here.

Has meaning current ?

Absolutely not. Any 'oddballs' you have date from roughly before 1960.

Graham

 

[Eeyore]

a round pin 2 amp plug that says it's for table lamps which oddly enough has
three prongs just like the big clunky plugs, got a few of those

BS546. Long obsolete in domestic use.
http://en.wikipedia.org/wiki/BS_546

Graham

 

[Spurious Response]

The lack of appropriate machanical stress handling is my biggest rejection of
the American type 130V power plug system, in addition to extremely poor design
of those flat contact receptacles, which wear out very easily, giving poor
contact with all bad things to follow..

Sleeves and pins... blades and wipers. They both sport similar life
spans and contact mating particulars, and neither is a clear winner, and
BOTH are used in higher power commercial scenarios. They are both proven
winners for the industry.

As far as our "130V" (120V actually) 2 and 3 prong plugs and
receptacles not having strain relief... they don't need it. If one
remains within the specs for their use, the outlet/plug combo never sees
any particularly high mechanical stresses placed on it. The bladed type
actually fights mechanical stress in one plane far better than pins do
without harming contact mating integrity over tens of thousands of stress
cycles.

 

[Eeyore]

Am 29.06.07 11.50 schrieb Eeyore:

Sure it is!


Here you are wrong.
The Euro plug is a flat, 2 prong, 4mm round contact plug, with pins 17mm
apart, fitting into regular 16A/240V outlets, but meant only for low power
devices. Its current rating usually is only 2,5A and they are widely used for
connecting consumer electronics (where the other end of the cable often is
pluggable too, having the 8-shape socket, if you look at it, with 2 small
receptacles 10 mm apart), small AC/DC power supplies, 240V to 2...24V
transformers and such.

They fit into the round 5mm receptacles of German type 3 contact "Schuko"
sockets, where the plug body actually dives into the outlet cover by some
20mm, allowing it to take on mechanical forces applied to the cable, rather
than having the contacts themselves deal with it.

It is not a standard *Euro* plug and is only suitable for 2.5A

Its proper name is CEE7/16.

Graham

 

[Dave Plowman (News)]

Just the opposite. The Euro plug is not designed that you can travel
across Europe with your 3680W water boiler and plug it in everywhere,
but for all those <= 575W gadgets, people like to have with them, while
they are travelling, but also for devices being fully insolated, hence
mot requiring the protective ground like VCR, TV, RCR, audio
amplifiers, satellite receivers, battery chargers, etc, etc.

You take those with you when you travel? ;-)

But it won't fit a UK outlet due to the shutters - so not a true Euro plug.

 

[John Larkin]

I've replaced a number of two prong outlets in my house (vintage 1928)
because the outlets failed in just the manner described. I don't know
the actual vintage of the particular sockets involved--although it's
pertinent that no two were the same, leading me to believe that they
themselves were later replacements for the originals.

In some cases it was possible to easily rewired with grounded 12/2 romex
from the breaker box. In others, where that was not practical, the
two-prongers were replaced with new outlets--also two prong.

These are still available and should be used if upgrading to a properly
grounded outlet is not done.

In any case, IME the OP's statement is entirely accurate. The
edison-style outlets are either inherently--or at least 'as
implemented'--prone to losing secure contact.

They are about the same as the IEC connector on the other end of most
power cords. No big deal.

I think that the number of deaths from US-style outlets is minute.
Electrocution and electrical fires result mostly from bad/old house
wiring and faulty appliances.

Germany runs about 1 PPM annual risk of death from electrocution, with
the USA closer to 2 PPM. That's not a lot of risk. I recall reading
that the majority of electrocutions in the US are on construction
sites, things like machines and ladders hitting high-voltage lines.

Really, cars are hundreds of times more dangerous than electricity,
and cigarettes 10x again. If Europeans want to save lives, they should
discourage smoking.

John