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Joined: Jan 2005
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If the idea of having 240V outlets for imported European kitchen appliances does catch on you might be able to just do that  Imagine - first it's kitchen appliances, then space heaters in all other rooms, as those receptacles spread, grey imports of 230/240V entertainment equipment will go up... until lighting is the only 120V stuff left in the US  My way would have the lighting on 12V (and power the transformer from 240V). Anyway, why force Schuko countries to switch to the French system? Polarization is most important with Edison base lights and those floor and table lamps are mostly double isolated and have Euro or contour plugs that can be reversed anyway. I think having both systems and phasing out the production of proprietary plugs (making all new plugs of the combined type, I think CEE 7/7 it is) is the best solution. I don't see any reason why polarization is needed. I don't even see a need for a grounded conductor supplying current, either. Equipment would need to work that way to be safe on 240V in North America ... and reportedly some isolated remote parts of Norway, Spain, and Russia still on the pre-war 220/127 system with line-to-line power. Manufacturers wishing to export to USA would need to make stuff work somehow on the 120/240 system we have over here. And this is not hard to do. Just don't design in any assumption of a grounded conductor. Make sure every insulation is suitable for a full 240V potential relative to anything else. Then with works fine on 230-0, 0-230, and 120-0-120. A UPS could be trickier since it would have to match the supply with its inverter output if there is any transition between systems. Regarding the age old UK problem - what if one split up a 32 amp ring into two 16 amp radials by adding an MCB and disconnecting one part of the ring? Same amount of power available for the cost of two MCBs and French sockets can be used without any trouble. That might work, but you would not have the liberty of putting the appliances that add up beyond 16 amps anywhere in the whole original ring. Just leave the ring connected, and put each end of the ring on a separate 16 amp MCB. If the circuit becomes open on one end while over current for one breaker, it trips.
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Joined: Mar 2005
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The reasoning was [and is]- how many folks will draw more than the allowed 30A on a 230v circuit? We don't have 120v POCO supply in Britain, nor 3-phase in domestic premises. A broken ring hot is a rare event, but could cause overheating problems in extremes. It was allowed after WWII because we were busted but had to rebuild after 5 years of bombing, using the least amount of copper. The system is definitely out of date, considering modern heavy use of electricity, and some UK builders do use 20A spurs now as an alternative. The ringmain is usually restricted to separate ring[s] per floor area of no more than 1000 sq feet, not the whole dwelling on just one ring. Most sockets actually run lowpower stuff like bedside lights, food mixers, a vacuum cleaner [drawing maybe 4A], or a toaster. The tv/DVD etc might pull 2A. Electric kettle 12A max if 3000W. That leaves portable electric fires, which are usually drawing 4-12A. If you are running 6kw of freestanding electric fires at today's energy costs, you are certifiably  blblblblbl!
Wood work but can't!
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Joined: Jul 2002
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Just leave the ring connected, and put each end of the ring on a separate 16 amp MCB. If the circuit becomes open on one end while over current for one breaker, it trips.  Having two points of supply to one circuit I believe is illegal in most places, it raises a real safety hazard.
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Joined: May 2002
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Surely you could just hard link the twin breakers like US 240V 3-wire circuits - 1 side of the ring blows and it takes down the other. However back to this non recessed socket design - there are many on the European market that don't require springs or moving faces to break or wear out - BS1363 comes to mind, and it's polarised!
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Joined: Sep 2005
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The Schuko design has been patented in 1926. Discussions in the 80s made clear that it would not last forever and as a result http://en.wikipedia.org/wiki/IEC_60906-1 was proposed. It is much smaller although it can as well carry 3600W. Today I'm not sure whether this new plug will really be introduced. I believe that sooner or later a fourth contact will appear, something one could call "Function Earth" to distinguish it from "Protective Earth". It will carry all this current caused by filtering and smoothing of the sinus wave, which today misuses the PE path and causes many problems.
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Joined: Dec 2002
Posts: 1,253
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Just in response to the numbers of outlets in homes. We've a 4-bed house in Ireland, just did a rough count of number of circuits and sockets (outlets)
Master bedroom : 4 doubles (8 outlets)
Bedroom 1: 3 doubles (6 outlets)
Bedroom 2: 2 doubles (4 outlets)
Bedroom 3: 2 doubles (4 outlets)
Bedroom area Hallway : 1 double (2 outlets)
Main Hallway : 2 doubles (4 outlets)
Sitting room : 4 doubles (8 outlets)
Dining room : 2 doubles (4 outlets)
Living room : 3 doubles (6 outlets)
Kitchen : 7 doubles (14 outlets)
Utility room : 3 doubles (6 outlets)
Garage : 1 double (2 outlets)
Basement : 1 double (2 outlets)
Attic : 1 double (2 outlets)
12 radial socket circuits - mix of 20A and 16A MCBs
The kitchen takes 3 of these.
Utility room takes 2.
Other rooms take 1 each
+ some miscellaneous for hallways / garage etc.
That's the original layout as per 1976, the distribution panel was upgraded a few years ago.
Total loading is actually pretty small, it's just handy to have outlets where you need them!
Also, there's absolutely no way you can overload an Irish panel as there's a master-breaker which will trip if you ever try to run more than the designed supply. (typically 63A, 80A or 100A)
Main fuse / master breaker has always been required. It saves any risk of people blowing the service fuse as it will react quite fast.
Also, the new Irish regs have banned the use of ring circuits in kitchens / utility rooms.
They're generally not used in most installations here, but they are technically permitted. They're just not the 'done thing'.
Last edited by djk; 05/29/09 07:34 PM.
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Joined: Dec 2001
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... and reportedly some isolated remote parts of Norway, Spain, and Russia still on the pre-war 220/127 system with line-to-line power. As are some areas of Belgium and Germany (mostly suburban Berlin). I am pretty sure though, if the US actually "get accustomed" to 240V for general household circuits power companies are likely to eventually start using 240V phase to neutral transformers as they replace old 120/240V ones. Just a scientific guess though. IMO the whole "Is Schuko good or not?"-discussion is missing one important point - as someone called it in German "die normative Kraft des Faktischen", I guess that translates to "the standardizing force of facts". They are simply everywhere, and replacing them would cause incredible trouble. Heck, not even the transition from ungrounded 2 pin plugs to Schuko/Euro/Contour plugs worked properly! There are still hundreds of thousands of old plugs in use, either in old sockets of filed/broken down to fit Schuko sockets, even though they were banned more than 30 years ago! Not only electricity takes the path of the least resistance
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Joined: Jul 2005
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[quote]I am pretty sure though, if the US actually "get accustomed" to 240V for general household circuits power companies are likely to eventually start using 240V phase to neutral transformers as they replace old 120/240V ones. This is something I've contemplated for some time, and if implemented would certainly increase efficiency. Residential use of 240V seems to be increasing in the U.S. From what I read around the internet, European kitchen appliances seem to be largely driving this, but these days with the ease of migration and overseas purchasing, ordinary 240V domestic appliances are being brought in privately. (In the 1950's with large scale European immigration to Australia, many migrants brought their appliances with them). I think a possible 'U.S conversion to 240V' might go along the lines of a small 240-120V transformer installed in the house to power the millions of low power appliances in existence. I doubt Shuko type plugs would be used as they already have 240V socket designs and it would be pointless and annoying to introduce something new. Incidentally, the reason why Australia chose an American plug and socket design was the ease of making flat pins rather than round ones.
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Joined: Dec 2002
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Well, it does make sense to have a properly polarised connector. There are quite a few desirable reasons for it, not just the lamp issue.
I really can't see any reason why we need to have CEE 7/4 (Schuko) and CEE 7/5 (French) side-by-side in Europe. They're both similar specifications and achieve exactly the same purpose, while accepting a common plug!
CEE 7/7 plugs fit both, thus allowing backwards compatibility with CEE 7/4 (German Schuko with the side earth clips).
All they'd have to do is phase out the side-earthed schuko sockets by simply banning their supply and removing them from the regulations in EU countries using them.
Most existing appliances' plugs are already CEE 7/7 so fit either French or German style outlets.
When CEE 7/7 plugs are used with French sockets and the socket is wired correctly they are polarised.
There is also a version of the contour (ungrounded) plug which has a flat slot on one side (enough to allow a schuko grounding clip to pass) and a round slot on the other (to allow a French grounding pin to pass).
It fits side-earthed schuko sockets as normal, but only goes into French style sockets in one polarity.
Thus, it provides a polarised non-grounded plug.
Then the existing flat 2.5amp reversible plugs could continue to be used with small appliances where polarity really doesn't matter.
I'd much rather see a robust standardised French outlet in use across europe, complete with shuttering.
At present there's far too many national variations of the same thing. Same plug might fit, but the safety standards aren't the same.
Also, if they want the UK and Ireland to switch over, the proposed EU-wide solution would have to be safer than BS1363 and the current CEE 7/7 set up simply isn't.
Last edited by djk; 05/30/09 07:13 AM.
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Joined: Sep 2005
Posts: 153
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Well, what about switching over to LHD?  Nobody really wants it, just take a short look at the chaos of European TV-standards. Wolfgang
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Posts: 5,445
Joined: January 2005
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