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Joined: Dec 2001
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Unfortunately CEE 7/7 plugs are not that common, newer molded appliance plugs are indeed usually 7/7, but extension leads, plug strips and most important rewirable plugs usually aren't.

I guess in order to see a serious need for polarization one has to have grown up in a country with polarized plugs... the only situation where I ever thought a polarized plug might be helpful was people digging around with knives in toasters, tripping the RCD in the process (only single pole switch and plugged in switching the neutral).

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pdh Offline
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Originally Posted by Trumpy
Originally Posted by pdh
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.


No way!! mad
Having two points of supply to one circuit I believe is illegal in most places, it raises a real safety hazard.

I was asking in the TECHNICAL sense, not the code/legal sense. If a ring is legal in UK, they (and perhaps they alone) might consider it to be just as OK to have separate 15 amp breakers on each end of the ring, compared to both end of the ring on a common 30 amp breaker.

The only issue I see being a technical problem is making sure the two 15 amp breakers are on the same phase when dealing with a 400/230 three phase supply. If not, you're gonna have a couple breakers pop off real fast.

The other issue is economic ... TWO breakers.

I'd rather just see them drop rings altogether (since I don't consider having both ends on the same breaker to be safe). But I don't live in UK, so it's not my issue.

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Originally Posted by Texas_Ranger
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.
I'd believe it, although it could take quite a long time. It wouldn't bother me. Then I'd want to get a 240/480 2-pole feed grin

Originally Posted by Texas_Ranger
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!
And today, there are so many more plugs and sockets to replace in every continent. It would be expensive. A 100 year phase out might work.

I was visiting a house this evening for a party of a friend of a relative. It appeared to have been built in late 1950's or early 1960's. All the outlets were the old ungrounded T-slot. That mates with ungrounded NEMA 1-15, 1-20, 2-15, and 2-20 plugs. And I thought those had been phased out of existence. But there they were. I was almost ready to offer them money for them. I also wanted to see what kind of old fuse panel they had grin

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If you supply a circuit from 2 breakers, how do you make sure they're always both off? Linking the handle only works if they're operated manually, if one trips it might not have enough force to trip the other with the free trip mechanism which is mandatory in Europe.

I don't believe in fusing circuits above the capacity of outlets anyway. In Continental European countries there's a simple rule: the smallest outlet on the circuit determines the fuse/breaker. So if an outlet is rated 16 amps, then it's no more than 16 amps, period. The UK tried avoiding this with the plug fuses without too much success. The US allow for 15amp outlets on 20amp circuits, posing a serious risk of overloading plug strips.

Let's face it - unless we're talking about large appliances like ranges, all-electric dryers or others (wired to dedicated circuits anyway), 16 amps at 230 or 240V are a lot of power. Why do you really need more than a few such circuits?

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djk Offline OP
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Originally Posted by Texas_Ranger
The UK tried avoiding this with the plug fuses without too much success. The US allow for 15amp outlets on 20amp circuits, posing a serious risk of overloading plug strips.


I wouldn't agree with you that the UK BS1363 system has had limited success. It's very successful.

While I'm not a major fan of rings, they are installed in millions of British homes and have proven to be flexible and safe.

In Ireland, we typically use 20amp radials with 13Amp socket outlets and fused plugs.

There are no non-fused plugs that are compatible with BS1363 socket outlets. It's as simple as that. While, it is possible to stick a CEE 7/16 plug into the outlet, it requires overriding the shutters with a tool which is a bit of a pain in the rear-end, and next to impossible on some of the more sophisitcated sockets e.g. MK brand. Larger European plugs simply do not fit the slots as the pins are slightly too wide.

With the BS1363 fusing system, at the very least the appliance and outlet will be protected at 13A, and because the majority of appliances are now shipped with molded-on plugs, they have the correct rating fuses installed. So, things like TVs, Set top boxes, lamps etc are normally protected with a 3amp or 5amp fuse, depending on rating.

There's absolutely no way you can overload a UK/Ireland power strip as the fuse in the plug will blow. The only way you could have a problem is if you used a non-fused power strip while on vacation on the continent with a CEE 7/7 plug on the other end.

The other major difference in the UK and Ireland is that we deliberately moved to a system which was designed to force standardisation by making all other systems obsolete and not allowing backwards compatibility. This was not the case in continental Europe or North America where backwards compatibility with old plugs and outlets was maintained.

If you do come across an old BS546 outlet, or schuko in Ireland (very very rare now) you simply cannot fit a modern plug into it, nor can you fit an old plug into a modern socket outlet.

The net result of this was that in the UK and Ireland you will only find one totally standardised type of socket and one totally standardised type of plug. There are no variations. They're all grounded, all shuttered and since the late 80s, all have sheathed pins.

The major downside of the system is that the plugs are quite bulky, requiring a plug roughly the size of a CEE 7/7 even on the smallest appliance.

I'd suspect that it's HIGHLY unlikely that we'll ever re-standardise simply because we've been through all of this before and it was a mess of adaptors for decades.

It's highly unlikely that since we finally got shut of the old round-pin plugs and sockets that we want to go through yet another re-standardisation smile

Also, anything that was proposed would have to provide significant safety advantages over BS1363. CEE 7/7 doesn't do that.

Last edited by djk; 06/01/09 08:26 PM.
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"The major downside of the system is that the plugs are quite bulky..."

Don't forget the fact that they always seem to lay pins up. So you can step on them! cry

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Indeed, plug strips can't be overloaded. However, unfused spurs can and that's a classic "DYI" feat I guess. I remember quite well how PaulUK described endless 1mm2 spurs off 30 amp rings feeding lord knows what.

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Originally Posted by Texas_Ranger
I remember quite well how PaulUK described endless 1mm2 spurs off 30 amp rings feeding lord knows what.


I would imagine anything of 1.0mm˛ calibre
would be lighting, but even so, it has no right being connected to a 2.5mm˛ circuit that is fused at 30A.

Edit: Unless the fused spur unit actually had a 10A fuse in it.

Last edited by Trumpy; 06/09/09 06:13 AM. Reason: To add edit point
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Originally Posted by Alan Belson
Most houses in the UK with a DIYer in residence usually run an unbelievable number of double or treble outlets, as some sort of Chav fashion statement! DIY use is where the real risks of overloadings occur, particularly with welders and big woodworking machines illegally installed by 'weekend warriors' without 'Part P' Local Authority approval or inspection.


Ahh, yes, the Chav's. mad

I recently rewired my workshop here, with a new 6mm˛ feed cable from the switchboard in the house, run over a catenary wire (overhead) and installed a new sub-main board with RCD's and a non-RCD socket for my MIG welder and stick welder, new lights, computer sockets and data cabling.
It all came to about NZ$500 all up, it was done properly, no hassle, I think I did it all in a weekend, which wasn't bad going, considering I had the flu and all of the sub-circuits had to be run in PVC conduit (concrete block walls)

It doesn't take much to do a good job Alan, just a bit of thought and pre-planning, people that have endless screeds of bodged up wiring, cobbled onto dodgily connected fittings are just asking for trouble.

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Originally Posted by aussie240
[quote=Texas_Ranger]
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.


In a sense, residences in the USA are fed 240V, but with a centertap tied to ground. Our electric ranges are powered by a usually 50A 240V circuit. So are larger room air conditioners, usually with a NEMA 6-15 outlet (240V 15A). And you could provide such an outlet in the kitchen for the European kitchen equipment (though you'd probably want or need GFCI protection on it).

Smaller loads get 120V, and the big stuff 240V. The 240V loads usually won't care that the hot wires are just 120V above ground vs 240V above ground.

I've heard that construction sites in the UK provide 110VAC for power tools, and this 110V is centertapped, and that is grounded. So the hot wires are just 55V to ground. In a similar method, someone grounded touching a hot wire on a 240V circuit will only(!) see 120V, not 240V.

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