Earth in EU/USA plug sockets

[Faringdon]

Hi,
We see lots of two pin plugs in the EU.
Do some EU wall sockets not actually have an earth connection?
In other words, any device connected to them would have to be in a plastic case, with no vent holes?
(ie double insulated)?

Ditto question for USA/Australia/China/Canada/Brazil and South America.

[themadhippy]

We see lots of two pin plugs in the EU.

look closer , them there schukos do have an earth

[IanB]

The sockets have an earth connection. The plugs are not required to make an earth connection if the connected device does not demand it.

[Swake]

Some older (like +40 years old) installations do not have an earth. Unfortunately not everyone has had the possibility to upgrade. Although public places should all have earth.

[tooki]

Hi,
We see lots of two pin plugs in the EU.

They’re common everywhere except the UK, basically. Many devices don’t need a ground. Even in the UK, you have devices with a plastic or disconnected earth pin.

Do some EU wall sockets not actually have an earth connection?

No. Excluding possibly some very old legacy installs that haven’t been updated in the better part of a century, earthed sockets are universal almost everywhere, as required by law.

You can look up the basic rules yourself, it’s not hard.

And as others have said, the Schuko plug (whose name literally is short for “protective earth contact” in German) has earth, it’s just a clip instead of a pin. The French plug also has no earth pin: the earth pin is in the receptacle, and the plug contains a female earth contact.

In other words, any device connected to them would have to be in a plastic case, with no vent holes?
(ie double insulated)?

That is not what double-insulated means. “Double-insulated” (Class II) means that the failure of one level of insulation cannot result in the user coming into direct contact with a mains conductor. This can be multiple layers of insulation, or reinforced insulation. It doesn’t mean all-plastic, and it doesn’t mean no slits. (Lots of AC-powered home AV gear is Class II, with the double square symbol, but is in a metal case with ventilation slits, using no earth.)

Ditto question for USA/Australia/China/Canada/Brazil and South America.

The standards vary by country; South America isn’t a monolithic electrical system. There’s a hodgepodge of voltages and plugs down there, sometimes even within a country.

The only country I am aware of that basically never uses earthed sockets is Japan. Everywhere else, earthed sockets are the norm (though in developing nations it’s not uncommon for the earth pin to not be properly connected!). But unearthed appliances are widely used.

So what is if you really want to know??

[Siwastaja]

Depends on exact country, but very generally:

1) Two-prong europlug: fits all sockets: obviously europlug socket, schuko (earthed) socket, and old-school unearthed 2-prong socket.
device must be double insulated and inherently safe against single failure regardless of potentials or faults in surrounding things.

2) Earthed plug: fits schuko (earthed) socket. Device does not need double insulation, because installation is made safe by having all metal cased things connected to the same potential through the earth connection, so no significant current can flow through the user if they touch two metal things at the same time, one of which is faulty. In theory, at least - assuming the earth connection is something that can't fail!

Then we have the case of old-school non-europlug two-prong non-earthed (round) plugs and sockets, well predating 1980-1990 or so. As double insulation was not required, they were made safe by the fact that such non-earthed sockets only exist in so called "dry" rooms with no plumbing, other sources of earth connections, not even earthed sockets. Basically this is a "floating" system. You would need two devices to develop simultaneous faults, one exposing line and another neutral into their cases, which is unlikely. Old legislation made it illegal to use extension cords to bring earthed supply into such rooms, for example.

These old single-insulated plugs and sockets have been phased out in all of Europe long time ago AFAIK, but you can still see them in old houses. There is no absolute urgency to upgrade because quite frankly, they never caused too many accidents. People modifying single-insulated equipment by cutting holes in the plug allowing it to plugged in rooms where it should not be operated was a real problem though, as the separation to different types of sockets as per room was a big convenience problem. Getting earthed sockets everywhere was the right choice, and later, GFCI/RCD made earthed installations truly much more safe.

(Before RCDs, earthed installations provided some false sense of security, as they completely relied on everything being correctly built with utmost care in the earth connection. If a product had dangerous earthing issues, then the surroundings of having everything else properly earthed made the thing more dangerous than what it would have been in the "floating" 2-prong "dry room" setting.)

[Lucien Nunes]

There's some interesting history behind why much of the world has the option of non-earthed plugs but the UK does not. As explained above, most systems that offer both earthed and non-earthed plugs for Class I and Class II equipment respectively, are designed so that both types fit the same earthed sockets.

In Europe, for class II equipment with low current requirements, the standard choice is the CEE7/16 Europlug, which is specifically the flat 2-pin plug rated at 2.5A with 4mm diameter pins angled slightly inwards. This is designed to fit all types of socket with 4.0-4.8mm contacts on 19mm centres, regardless of whether the socket has an earth. Thus the same plug suits countries with CEE7/1, 7/3 (Schuko), 7/5 (French etc.), Swiss, Danish, Italian, IEC 60906 (Brazil, SA) and obsolete types too. There are also higher-rated non-earthed variants such as CEEE7/17, which allow for 10A or 16A loads but only interface to a smaller selection of sockets. All of these, ultimately, are descended from and semi-compatible with an early non-earthed plug by Siemens, designed at a time when earthing was not widespread.

Then in the USA and systems derived from the NEMA standards, there is the 2-prong NEMA 1 type, which fits both legacy NEMA 1 outlets, and the standard 120V NEMA 5-15 and 5-20 grounded outlets. As with the European system, the basic non-grounded plug fits almost every outlet that has the correct voltage, and is descended from an original design by Hubbell that was created before grounding was commonplace. Less widespread but fundamentally similar is the Australian / NZ plug which can also exist in 2- and 3-pin compatible versions.

The UK's BS1363 plug is a special case for which there has never been, and cannot be, a non-earthed 2-pin variety. This is because the mechanism in many sockets, and as envisaged in the original specs, required the earth pin to open the safety shutters. If we don't need an earth pin for earthing, we must still have a plastic replacement for it, called an ISOD (Insulated Shutter Opening Device.) Part of the reason for BS 1363 being so different to many other plugs is that it was one of the most recent designs, from 1947, that was not compatible with any of its predecessors. But what about those predecessors?

This is where the old UK system starts to look very daft. Before 1947, we had three current ratings of plug (2A, 5A, 15A) with round pins, each available in earthed (3-pin) and non-earthed (2-pin) versions. But, although the line and neutral pin dimensions were the same for both versions, they were made to different standards and had different spacings between the pins. Therefore a 15A 2-pin plug did not fit a 15A 3-pin socket, and likewise for 2A and 5A. Thus there were six completely incompatible types in use plus a few specials like the Wylex.

So, in 1947 we had a re-think to get rid of this confusing array of different plugs, and came up with the fused, earthed plug that is BS1363. By this time, earthing was widespread, but the vast number of small Class II electronic goods that we use today didn't yet exist. So it probably seemed that there was little point designing a 2-pin non-earthed version of the plug that would complicate the shutter arrangements. As things have turned out, countries that had a non-earthed variant all along have ended up with a neater solution for small electronic goods today, while we have our later, 'better' plug that forces us to the larger earthed variant footprint even when not needed.

[mariush]

In Romania, in apartment buildings made before the revolution (1990) it was common practice to only have Earth wire at a socket near the bathroom (for washing machines or hair dryers) and one in the kitchen. It was all about saving money, cables going to ac sockets were  using copper, cables going to lightning were made of solid core aluminum.
 
Nowadays, I assume they would route earthing wire to every socket, as the wires are not that expensive.

[IanB]

So, in 1947 we had a re-think to get rid of this confusing array of different plugs, and came up with the fused, earthed plug that is BS1363. By this time, earthing was widespread, but the vast number of small Class II electronic goods that we use today didn't yet exist. So it probably seemed that there was little point designing a 2-pin non-earthed version of the plug that would complicate the shutter arrangements. As things have turned out, countries that had a non-earthed variant all along have ended up with a neater solution for small electronic goods today, while we have our later, 'better' plug that forces us to the larger earthed variant footprint even when not needed.

There was, however, a 2-pin non-earthed plug in widespread use into the 60's, which was basically the same geometry that became today's shaver plug. But back then, it was commonly attached to the two conductor cord of non-earthed appliances like lamps, toasters, radios and all sorts of things. The plug was simple, did not have plastic sleeves on the pins, and the socket was not shuttered. When BS1363 became common, the readily available shaver adapters allowed these two pin plugs to continue in use (it was often easier to use an adapter for the existing plug than to change the plug on the cord).

When I was growing up I used these two pin plugs as a convenient mains test fixture for powering things on the workbench as it was easy to attach a two conductor zip cord to them without needing a screwdriver. You just unscrewed the cap of the plug, put the conductors through the connecting lugs, and screwed the cap back on. It took just seconds.

[wasedadoc]

The (UK) house that my parents lived in for almost all of their married life was built sometime around 1951.  Originally all the socket outlets except the one for electric kettle in the kitchen were made by Dorman-Smith.  A 3 pin design with the earth pin diameter slightly larger than the other ones.  The unique aspect was that the plugs were fused but the fuse was not internal to the plug.  Instead the fuse was the live pin.  Imagine a slightly larger version of a current BS fuse as used inside today's 13 Amp rectangular pin plug but with the metal cap at one end having a protruding threaded portion about 6mm long. That end screwed into the threaded live contact inside the plug body. The fuse acted as the pin with the plain metal cap end going into the socket.  Different ratings of the fuses were available to screw in.

Pictures 6 to 10 at https://www.plugsocketmuseum.nl/DormanSmith1.html

[Haenk]

In other words, any device connected to them would have to be in a plastic case, with no vent holes?
(ie double insulated)?

Earth is not needed when double insulated, but it's not depending on the material of the case. Metal casing is totally fine, even with lots of venting holes. However there are test procedures poking with things into the case - the venting has to be small enough, to be not able to touch anything inside, like with a knife or a pen.
Plastic casing is only used due to being cheaper and being easier to mold into some stylish object (versus plain old metal box). Of course you have the benefit of screwing stuff directly into the case without needing to care about insulation.

[dmills]

The only country I am aware of that basically never uses earthed sockets is Japan.

The Philippines is I think another one that is frequently ungrounded in places that Western Europe would expect to be.

They actually have both grounded and ungrounded sockets, but just because something has a notional 'ground' contact, it should NOT be assumed to be connected (And if it is, it might just be wired to local neutral!).

Very different attitude to electrical safety over there.

[dmills]

Lots of hifi gear is double insulated in metal cases, basically because the double insulation is easier then reliably solving the earth loops in single ended IO connections any other way.

This does sometimes result in a tickle when you have a load of double insulated laptops or such hooked up as the leakage current tends to sum and can get high enough to be very obvious.

Apple lapdogs when plugged into a double insulated video projector and cheap class D powered speakers can be especially fun for this as they have a metal case connected to the negative side of the power supply, can sometimes get rather spicy. Cure is to earth any random bit of the setup.

[tooki]

The only country I am aware of that basically never uses earthed sockets is Japan.

The Philippines is I think another one that is frequently ungrounded in places that Western Europe would expect to be.

They actually have both grounded and ungrounded sockets, but just because something has a notional 'ground' contact, it should NOT be assumed to be connected (And if it is, it might just be wired to local neutral!).

Very different attitude to electrical safety over there.

I know that. I said that in the part of my comment that you cut off:

The only country I am aware of that basically never uses earthed sockets is Japan. Everywhere else, earthed sockets are the norm (though in developing nations it’s not uncommon for the earth pin to not be properly connected!).

The point about Japan is that they’re NOT grounded outlets with the ground not connected, but rather that 2-pin sockets are still the norm there. Grounded appliances come with a ground wire that you have to screw to it instead (so hilariously, there is a ground wire in the wall, and it leads to screw terminal on the outlet, rather than a pin receptacle!).

[langwadt]

plenty of plugs and sockets with no earth here, and most devices will be delivered with a schuko plug that fits but doesn't connect earth in a Danish socket

[newbrain]

Is any country apart from Sweden using specific plugs and sockets for ceiling mount light fixtures?

All apartments I've seen either have the old style ones or the EU-standard DCL ones.

I don't remember seeing those ceiling sockets anywhere else in EU or UK/US/CA/BR, definitely not in IT.

[themadhippy]

Is any country apart from Sweden using specific plugs and sockets for ceiling mount light fixtures?

Theirs a few about in the uk,hagers klick rose  https://www.tlc-direct.co.uk/Products/ASPCR2000.html  being the one ive seen the most  .There pretty rare in  domestic environments,more often found in commercial buildings.

[Haenk]

plenty of plugs and sockets with no earth here, and most devices will be delivered with a schuko plug that fits but doesn't connect earth in a Danish socket

About 3 years ago we were in an old feriehuset, which was great in having old 2-prong wiring and Schuko-adapters all over, even in bathroom and kitchen. The dryer in the bathroom required an earthed connection (as stated on the label) and had *very* noticable leak to the chassis. So much I considered it unsafe and forbid my wife to use/touch it when plugged in. Switched it on with that well known remote broom.

As for the swedish ceiling sockets - I have only seen those in Sweden, and I find them great.

[Siwastaja]

All apartments I've seen either have the old style ones

We use(d?) that exact type here, too. Before around 2000's, there was simply a terminal block in the ceiling and it was considered normal to wire it up yourself.

[langwadt]

Is any country apart from Sweden using specific plugs and sockets for ceiling mount light fixtures?

All apartments I've seen either have the old style ones or the EU-standard DCL ones.

I don't remember seeing those ceiling sockets anywhere else in EU or UK/US/CA/BR, definitely not in IT.

Denmark have these, https://sw5890.sfstatic.io/upload_dir/shop/category/Laurtiz-Knudsen---Lampemateriel---Lampestik.jpg

[langwadt]

plenty of plugs and sockets with no earth here, and most devices will be delivered with a schuko plug that fits but doesn't connect earth in a Danish socket

About 3 years ago we were in an old feriehuset, which was great in having old 2-prong wiring and Schuko-adapters all over, even in bathroom and kitchen. The dryer in the bathroom required an earthed connection (as stated on the label) and had *very* noticable leak to the chassis. So much I considered it unsafe and forbid my wife to use/touch it when plugged in. Switched it on with that well known remote broom.

Things like washing machines should be earthed, so they should at least have used a schuko to three-prong adapter

though, the leak was probably just the filter in the powersupply, unpleasant but not dangerous

 

[tooki]

Hi,
We see lots of two pin plugs in the EU.
Do some EU wall sockets not actually have an earth connection?
In other words, any device connected to them would have to be in a plastic case, with no vent holes?
(ie double insulated)?

Ditto question for USA/Australia/China/Canada/Brazil and South America.

You posted and then vanished.

I ask again (and this isn't a rhetorical question; I want an answer): So what is it you really want to know??

[Faringdon]

Thanks,
We want to produce a (400W peak) offline power supply for a product in EU. (+ elsewhere)
Thing is, power supplies for household items must be in totally enclosed plastic cases for safety reasons.........if you have that, then you need to have an internal metal foil  inside the plastic enclosure, otherwise you will not pass radiated EMC regulatory compliance testing.
...And if you have a metal foil surrounding the SMPS, then its best to connect it to earth...but if the two pin socket doesnt have an earth, then how can this be done?

Lots of AC-powered home AV gear is Class II, with the double square symbol, but is in a metal case with ventilation slits, using no earth

Thanks, may i ask what this metal case is connected to....or is it just "floating"?

[IanB]

but if the two pin socket doesnt have an earth, then how can this be done?

Where are you going to find a two pin socket with no earth in the EU?

[Benta]

Where are you going to find a two pin socket with no earth in the EU?

They're everywhere. Not every house was built within the last 10 years. You'll still find 1920s installations around.

[themadhippy]

Where are you going to find a two pin socket with no earth in the EU?

In the bathroom normally

[mzzj]

Where are you going to find a two pin socket with no earth in the EU?

They're everywhere. Not every house was built within the last 10 years. You'll still find 1920s installations around.

Here in Finland two pin sockets were banned in 1997 for new construction and 2022 in expansions to existing installations. Still commonly available on market and allowed for replacement for broken units.

[Benta]

In the bathroom normally

Those are for shavers and contain a 20 VA isolation transformer.

[tooki]

Thanks,
We want to produce a (400W peak) offline power supply for a product in EU. (+ elsewhere)

OK.

Thing is, power supplies for household items must be in totally enclosed plastic cases for safety reasons.........

Says who?

There are plenty of metal-housed devices, including ones with power supplies inside, with or without an earth pin.

if you have that, then you need to have an internal metal foil  inside the plastic enclosure, otherwise you will not pass radiated EMC regulatory compliance testing.

Says who? There are plenty of plastic-housed devices, including ones with power supplies inside, which do not use internal shielding. (What I mean is that internal shielding isn't a requirement per se. It is, however, often a sensible way to achieve EMC compliance.)

...And if you have a metal foil surrounding the SMPS, then its best to connect it to earth...

Not necessarily. (Bearing in mind that I'm at the limits of my knowledge on this point -- I just know there are name-brand devices out there that have completely floating shields.)

but if the two pin socket doesnt have an earth, then how can this be done?

Obviously it can't -- sorta.

Look at what SMPSs do to reduce EMI. EMI noise is AC, mostly at frequencies well above 50/60Hz. So what you do is to capacitively couple the secondary-side ground to the AC input using a small Class Y safety cap. The small value of the cap makes it high-impedance at 50/60Hz, but low-impedance at the high frequencies you want to arrest. Since the neutral side of mains is tied to earth somewhere, that's your path to earth. Since you don't know which AC wire will be neutral, you use another safety capacitor between secondary-side ground and the other AC wire. (This is why devices with unearthed SMPSs often tingle when you touch them: their ground is floating at 1/2 mains voltage, albeit at minuscule current.)

The end result is that no matter which way the plug is inserted, the secondary ground, to which your shielding is tied, is tied to earth as far as high frequency AC is concerned.

Lots of AC-powered home AV gear is Class II, with the double square symbol, but is in a metal case with ventilation slits, using no earth

Thanks, may i ask what this metal case is connected to....or is it just "floating"?

It's either truly floating or (often) connected to secondary ground.


With all this said, I'm no expert on this, and you would be remiss to not engage the services of an EMC consultant.


Also, when you say "offline", do you mean non-isolated? (There seem to be multiple competing meanings of what the term indicates...) Or what exactly do you mean?

[IanB]

Where are you going to find a two pin socket with no earth in the EU?

They're everywhere. Not every house was built within the last 10 years. You'll still find 1920s installations around.

So what do you do if you live in one of those houses and you buy an appliance that requires an earth connection? Do you use it (unsafely) without an earth, or do you simply not use such appliances?

In the UK, houses that pre-date modern standards were generally re-wired long ago. Not least because wiring that had rubber insulation (rather than PVC) became dangerous and had to be replaced.

[Benta]

Where are you going to find a two pin socket with no earth in the EU?

They're everywhere. Not every house was built within the last 10 years. You'll still find 1920s installations around.

So what do you do if you live in one of those houses and you buy an appliance that requires an earth connection? Do you use it (unsafely) without an earth, or do you simply not use such appliances?

In the UK, houses that pre-date modern standards were generally re-wired long ago. Not least because wiring that had rubber insulation (rather than PVC) became dangerous and had to be replaced.

I dunno where you've been in your life. Flag says US...

In a house without receptacles with earth, you just plug in the two-prong plug. Works fine in most EU countries. Otherwise adapters are available. Consumers are not electrical engineers. Whatever works, works.
And regarding the UK: I've been there often, and the electrics (not to mention plumbing) is a nightmare. Your "replacement" scenario must have been in a dream... or some luxury hotel.

[tooki]

I dunno where you've been in your life. Flag says US...

In a house without receptacles with earth, you just plug in the two-prong plug. Works fine in most EU countries.

FYI, that is a peculiarity of the Schuko and type F sockets (the only ones in use where the earth isn't implemented as a male pin on the plug).*

Everywhere else, earthed plugs are mechanically incapable of fitting into a 2-pin socket, e.g. USA, UK, Australia, or Switzerland.



*OK, fine: and the Japanese, with their weird earthed plugs that are just the 2-pin plug with a flying earth wire coming out the side!

[IanB]

I dunno where you've been in your life. Flag says US...

Britain. The USA is where I live, not where I'm from.

In a house without receptacles with earth, you just plug in the two-prong plug. Works fine in most EU countries. Otherwise adapters are available. Consumers are not electrical engineers. Whatever works, works.

You can't do that in the UK. All appliances are sold (by law) with a BS1363 plug attached to the cord, and any dwelling you can reasonably live in has BS1363 sockets on the walls. There is one single device you can buy in the UK that has a two pin plug, and that is an electric shaver. It will not plug into a BS1363 socket without an adapter, but that's fine because it's non-earthed device to earthed socket. There is no case in the UK of earthed device to non-earthed socket.

And regarding the UK: I've been there often, and the electrics (not to mention plumbing) is a nightmare. Your "replacement" scenario must have been in a dream... or some luxury hotel.

You can't live in a home in the UK that does not have BS1363 sockets installed, because no electrical devices you buy will be usable without.

[Monkeh]

And regarding the UK: I've been there often, and the electrics (not to mention plumbing) is a nightmare. Your "replacement" scenario must have been in a dream... or some luxury hotel.

Regarding the UK: I live here. I have done for quite some time. You perhaps want to wind your neck in, or redefine 'nightmare' not to include 'oh dear god two taps' and 'that socket isn't what I'm used to'.

[themadhippy]

There is one single device you can buy in the UK that has a two pin plug

you forgot the rechargeable toothbrush

You can't live in a home in the UK that does not have BS1363 sockets installed, because no electrical devices you buy will be usable without.

not even the old couple,still living in the house they moved into back in the 50's that hasn't had the wiring touched since and apart  from the new tv  ,all the appliances pre date the 1992 legislation?

[IanB]

You can't live in a home in the UK that does not have BS1363 sockets installed, because no electrical devices you buy will be usable without.

not even the old couple,still living in the house they moved into back in the 50's that hasn't had the wiring touched since and apart  from the new tv  ,all the appliances pre date the 1992 legislation?

That old couple is not me or you. And you cannot tell me that people are still using appliances bought in the 50's?

If you try to move into a house that has not been touched since the 50's, isn't it going to have trouble with the EICR?

[IanB]

I grew up in a house that was built in 1960, and the electrical system was fine but for two things: there were not enough sockets (e.g. one socket per bedroom was considered adequate), and the lighting circuits had no earth (was OK at the time with lamps and shades hanging from a ceiling rose). But all the sockets even then were BS1363 three-pin and earth.

[themadhippy]

And you cannot tell me that people are still using appliances bought in the 50's?

i didnt say 50s,i said pre 1992

isn't it going to have trouble with the EICR?

  on the first page of our  regs is states

Existing installations that have been installed in accordance with earlier editions of the Regulations may not comply with this edition in every respect. This does not necessarily mean that they are unsafe for continued use or require upgrading.

Welcome to the one of the many grey areas within the regs

[IanB]

i didnt say 50s,i said pre 1992

Yes, but 1992 is modern times. I bought a flat built in 1986 and the electrical installation was basically the same as today.

[Monkeh]

i didnt say 50s,i said pre 1992

Yes, but 1992 is modern times. I bought a flat built in 1986 and the electrical installation was basically the same as today.

He's obtusely referring to The Plugs and Sockets etc. (Safety) Regulations 1994 (I'm not sure why 1992 keeps coming up), which is when it became a requirement for products to have a BS1363 plug fitted at sale.

[IanB]

He's obtusely referring to The Plugs and Sockets etc. (Safety) Regulations 1994 (I'm not sure why 1992 keeps coming up), which is when it became a requirement for products to have a BS1363 plug fitted at sale.

Yes, I lived through it. All the product packaging had to change, because now they had to find space for a giant plug to fit inside the box without scratching anything, whereas before they could just have the loose end of the power cord tucked away and a card telling you how to fit a plug to it 

[Nusa]

Thanks,
We want to produce a (400W peak) offline power supply for a product in EU. (+ elsewhere)
Thing is, power supplies for household items must be in totally enclosed plastic cases for safety reasons.........if you have that, then you need to have an internal metal foil  inside the plastic enclosure, otherwise you will not pass radiated EMC regulatory compliance testing.
...And if you have a metal foil surrounding the SMPS, then its best to connect it to earth...but if the two pin socket doesnt have an earth, then how can this be done?

You're confusing product legal requirements with stuff that's never going to be under your control. If you provide the appropriate safety ground and advise using the appropriate grounded outlet, you've likely done your due diligence. If the user plugs it into his ungrounded house anyway, that's not your responsibility.

In the case of the US, residences only have to meet the codes as of the day of install, unless modifications trigger updated code requirements. Which is why there are still ungrounded houses out there, with people using all the usual things without an actual safety ground connected to the appliance. We are talking about places 50+ years old that haven't had major electrical updates, but there are quite a lot of those. I grew up in a 1925 house, and am currently in a 1955 house. The only outlets that have safety ground are the ones on the shop circuit I added and a handful of other outlets I've updated (my computer setup and the kitchen counter).

[themadhippy]

I'm not sure why 1992 keeps coming up),

old memory aint wot it used to be

Yes, but 1992 is modern times. I bought a flat built in 1986 and the electrical installation was basically the same as today.

86 was the 15th edition were some really stupid bonding rules were introduced ,rcd's wernt required  everywere,spd's were unheard off,plastic dis boards were considered modern and  the wires were prettier colours,just a  few  things that wouldnt meet  todays regs

[IanB]

86 was the 15th edition were some really stupid bonding rules were introduced ,rcd's wernt required  everywere,spd's were unheard off,plastic dis boards were considered modern and  the wires were prettier colours,just a  few  things that wouldnt meet  todays regs

Perhaps, but none of that affects the basic functionality of the electrical system. I don't know anything about the bonding rules, but the other stuff is just designed to make installations more expensive. People keep updating the regs because they have nothing better to do with their time (yes, I'm cynical).

[ejeffrey]

Where are you going to find a two pin socket with no earth in the EU?

They're everywhere. Not every house was built within the last 10 years. You'll still find 1920s installations around.

So what do you do if you live in one of those houses and you buy an appliance that requires an earth connection? Do you use it (unsafely) without an earth, or do you simply not use such appliances?

Yes. When I lived in the Netherlands I never saw a grounded socket in a residential setting except in the kitchen and bathroom.  It was all type C / CEE 7/1 outlets.  If you bought something with a shucko plug it would just get used ungrounded.  Not only that, but since it isn't recessed the pins would be slightly exposed during insertion.

[themadhippy]

but the other stuff is just designed to make installations more expensive

we came to the conclusion the regs were sponsored by the equipment manufacturers

People keep updating the regs because they have nothing better to do with their time

No No  No,its all for our safety.It also has nothing to do with them fleecing us every 2 or 3 years for a new set of books (around £100 for the regs and guides) or  the fees  every 10 or so years for taking another     how to read a book regs course and exam

[Faringdon]

Look at what SMPSs do to reduce EMI. EMI noise is AC, mostly at frequencies well above 50/60Hz. So what you do is to capacitively couple the secondary-side ground to the AC input using a small Class Y safety cap. The small value of the cap makes it high-impedance at 50/60Hz, but low-impedance at the high frequencies you want to arrest. Since the neutral side of mains is tied to earth somewhere, that's your path to earth. Since you don't know which AC wire will be neutral, you use another safety capacitor between secondary-side ground and the other AC wire. (This is why devices with unearthed SMPSs often tingle when you touch them: their ground is floating at 1/2 mains voltage, albeit at minuscule current.)

The end result is that no matter which way the plug is inserted, the secondary ground, to which your shielding is tied, is tied to earth as far as high frequency AC is concerned.

Thanks very much ....this sounds like the right way to do the secondary grounding when the product has no mains earth connection.
As you know, for some reason, it often doesnt get done...often, only one Y cap is used, and it is placed from the primary DC bus ground to the secondary ground. As you know, "primary dc bus ground" is alternately line then neutral, due to the Full wave bridge....and between "primary dc bus ground", and the incoming AC L or N wire, there are usually filter inductors, which would impeded the HF emission on its way back into the L and/or N wire....though maybe thats OK?...because it "filters" the emission?

There are plenty of plastic-housed devices, including ones with power supplies inside, which do not use internal shielding. (What I mean is that internal shielding isn't a requirement per se. It is, however, often a sensible way to achieve EMC compliance.)

Thanks, thats right...and  if they are more than about 30W, then they will not pass Radiated EMC to EN55032.
They get away with it because nobody checks them.
I actually worked in a place where their offline SMPS in plastic-with-no-metal-shielding failed Radiated EMC......and they just kept selling it.

[Siwastaja]

Where are you going to find a two pin socket with no earth in the EU?

They're everywhere. Not every house was built within the last 10 years. You'll still find 1920s installations around.

Here in Finland two pin sockets were banned in 1997 for new construction and 2022 in expansions to existing installations. Still commonly available on market and allowed for replacement for broken units.

And note this is about large round 2-pin sockets that can accept either an Europlug or an earthed Schuko plug (so that earthing would be lost).

It is not illegal at all to install 2-pin sockets, if they are europlug sockets. This is because you can only connect Europlug devices, which by definition are double insulated.

[Faringdon]

Thanks, yes, i think we all agree that there are loads of things that have no earth connection, and loads of mains sockets that give no earth connection.

It would be impractical to ensure that every socket in the EU had an earth connection...so the authorities simply  let that one slip.

But to pass radiated EMC to EN55032, any plastic enclosed offline SMPS of >75W, must comprise metal foil, or metal plate, or "metal net" lining, otherwise it simply wont pass Radiated EMC compliance testing to EN55032......i say >75W, because they contain a hard switching PFC stage.....some <75W smps are resonant, and can pass radiated EMC even if no metal lining.

The best way to get through EN55032 radiated EMC, is to have that metal lining connected to earth ground...but if no earth is presented, then as IanB [EDIT....sorry, Tooki]  puts it......there would hopefully be Y caps strategically placed connected to secondary ground, and these would effectively kind of connect the metal shield to earth ground.
If even y caps arent present, then the metal shield would hopefully be connected to some "quiet" node on the PCB...ie not a switching node....that would increase its chance of passing EN55032 radiated EMC.

As you know, in the testing house, they will have a socket available with an earth wire.

[IanB]

then as IanB puts it

That was not me. I think it was tooki?

[Faringdon]

Thanks, sorry about that..now Edited.

[DavidKo]

but if the two pin socket doesnt have an earth, then how can this be done?

Obviously it can't -- sorta.

It can be done same way as in old distribution where only 2 wires were used. Earth is connected to neutral in the socket.

This is more common than 2 hole sockets (it was prohibited for new installations cca. 30 years ago at our country).

[vk6zgo]

i didnt say 50s,i said pre 1992

Yes, but 1992 is modern times. I bought a flat built in 1986 and the electrical installation was basically the same as today.

He's obtusely referring to The Plugs and Sockets etc. (Safety) Regulations 1994 (I'm not sure why 1992 keeps coming up), which is when it became a requirement for products to have a BS1363 plug fitted at sale.

Yes, I learnt many years back that in the UK you could buy products with just plain leads, so you could buy plugs & fit them.

Not quite on topic, but, in 1971, whilst on a visit, I met some ladies who had returned to the UK, bringing an Australian radiogram & some other items, which had their cords changed to BS1363 plugs by a local "sparky".
They thought that because I was returning to Oz, I might be able to make use of the removed plugs.

I didn't have the heart to tell them the removed ones were all moulded types, of which Australia was an early adopter.