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#137586 07/19/03 11:38 AM
Joined: Dec 2002
Posts: 1,253
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djk Offline
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Also posted in the Swiss thread.. [Linked Image]

I really don't like the Danish plug. Of all of the systems in Europe it has one huge flaw.

From my observation the stubby earth prong seems makes contact after the live and neutral pins!! It could easily result in a metal body applience being momentarily live before a ground fault was detected.

On top of that I've seen loads of schuko plugs happily plugged in in Denmark with absolutely no earth contact.

I really can't see the reason for keeping the system as it's not compatible with any of the neighbouring countries and provides absolutely no advantages.

I was supprised that a scandinavian country would come up with such a system.

Schuko ground clips make contact before the phase and neutral make a connection.

The other three non-schuko round pin systems are similar:

The French system contacts the ground pin before any connection is made. It's pretty similar to schuko in most regards although has the advantage of being polarised when a grounded plug is used.

The swiss system has the advantage of being exceptionally neat and switzerland, from my observations, has very few ungrounded outlets and when used with grounded plugs is polarised.

Likewise, the Italian system is very neat and seems, when used correctly, to be at least as safe as schuko.

#137587 07/20/03 07:58 AM
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pauluk Offline OP
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DJK,
I've taken the liberty of deleting the duplicate in the Swiss thread. Hope you don't mind too much -- I've made a similar duplicate post myself in the past and found that it can lead to a lot of thread jumping and linking trying to piece different parts of the same line of thought together.

I don't think I've ever seen a Danish plug and socket. Does the earth pin really not make contact until after the line and neutral, or are the contacts in the socket for the latter set so far back that earth continuity is assured first?

The French outlets do indeed have the advantage of being polarized, but there doesn't seem to be too much attention paid to which way they're wired. I've seen so many wired apparently at random that I wouldn't like to guess which way is correct. Is there actually a specified standard for this? (i.e. With the ground at the top is neutral on the left or the right?)

Aesthetically, to most of us the French outlets with the male pin on the receptacle look more than a little weird to say the least. Perhaps they don't look quite so strange to those of you who are used to seeing Schuko?

#137588 07/20/03 10:58 AM
Joined: Sep 2002
Posts: 1,498
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C-H Offline
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Quote

Does the earth pin really not make contact until after the line and neutral, or are the contacts in the socket for the latter set so far back that earth continuity is assured first?

Don't know about the old ones which look just like BS 546, with a big round hole for the earth. These have a switch too, so you should not switch on the power until the plug is fully inserted.

The modern ones have the earth hole designed so that ut makes contact as soon as the pin enters the socket, whereas the other pins have a much longer way to go. I think this compensates for the short earth pin.

#137589 07/20/03 11:01 AM
Joined: Oct 2002
Posts: 134
D
Member
I like:
100A Single phase UK domestic supplies.
13A Switched shuttered sockets (not necessarily the ring main)
TNS & TNC-S systems which are the most prevelant in the UK.
I dislike:
UK twin & earth cables with reduced size bare earth wire.
Rewirable fuses which are still found in thousands of older UK installations.
The slow adoption of RCD's in the UK. Ireland for example has required all domestic sockets to be RCD protected since 1980. I would like to see this requirement here, perhaps enforced when a house is sold, as in Queensland, Australia.

I would not like to see un-polarized schuko sockets adopted in the UK, or continental style solid single core cables larger than 2.5sqmm. British cables are stranded over 2.5mm, with 1.5 & 2.5 available in both solid & stranded.

C-H,
You said, "how would you run a farm without 3-ph?"
Some farms in this area only have a "split-phase" 240/480V supply. The HV supply to the transformer only being a 2 wire spur, like the line in Paul's posting above. These supplies can often be found in more remote areas, although obviously 3-ph would be preferable the cost of upgrading may be prohibitive.

#137590 07/20/03 01:22 PM
Joined: Dec 2002
Posts: 1,253
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djk Offline
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The ESB's rural network is generally 3-phase but in spots where only single phase is available they'll just use multiple supplies to a farm where each transformer serves a different building etc.

These areas are ***very*** remote and single phase is gradually being "phased out" (bad pun) in favour of 3-phase as it severly restricts the type of machinary that can be used. E.g. single phase milking parlours are quite limited.

For very low population areas where a 10KV line might only be serving 2 small farms and associated farmhouses it generally poses absolutely no problems at all


There are lots of 10KV 3phase lines running around the countryside here, many of which are being upgraded to 20KV to cope with demand.

Power's distributed with lots of US-style pole mounted can type xformers stepping tapping into one of the phases and stepping it down to 220V 1-phase for domestic premsis or taking all 3 phases and providing 380V to farms.

On another point farm buildings are BY FAR the worst offenders for breeches in wiring code (serious ones)

E.g. Premisis are now actively inspected to insure that simple things are correctly done. E.g. it wasn't too unusual to find BS1363 or even BS546/schuko sockets in the middle of a milking parlour or cow shed! Totally illegal and really dangerous especially considering how easy it is for a cow to get badly electrocuted. Not to mention the fact that they could be sprayed, splashed or kicked!

Major education campaign has been going on for about 25+ years to get small farmers here to "cop on" it's finally working! But only since they've actually started random inspections.


[This message has been edited by djk (edited 07-20-2003).]

#137591 07/20/03 02:51 PM
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C-H Offline
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Well, farms are farms. Not much to do about that. I'd say that the wiring is one of the lesser problems in many old farm. Sometimes the buildings look like they will come down any minute.

#137592 07/21/03 06:11 PM
Joined: Nov 2002
Posts: 456
C
Member
Here in Canada, the smaller farms use single
phase 120/240 service (3 phase is used only on the larger operations), mostly using what is called a CMS system, where the transformer is on a pole central to the buildings, and has a current transformer and meter, with the buildings being
fed radially from the pole, either OH or UG.
Smaller buildings may be subs from larger buildings, rather than supplied from the
service pole.

Farmhouses usually have 200A service, 200A for buildings where a lot of motors are (such as a barn with feed handling or milking equipment) , and most other buildings have a 100A service.

#137593 07/21/03 06:17 PM
Joined: Nov 2002
Posts: 456
C
Member
On other things, I am partial to the concept of the fused plug, with 30A at the recepticle, but think radial circuits are easier than a ring.

The Australian plugs are good.

The Bayonnet base bulbs are safer too.

Switched outlets, only whe required I suppose. (>1500W perhaps)

I have mixed feelings about a whole home RCD, rather than the North American way of using GFCI only where warranted.

#137594 07/21/03 07:21 PM
Joined: Dec 2002
Posts: 1,253
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djk Offline
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Typically here in Ireland it's 20 A radials feeding BS1363 sockets and fused plugs/fused connections for fixed appliences (30 amp rings are sometimes used but not quite as much as in the UK)

#137595 07/22/03 06:22 AM
Joined: Aug 2001
Posts: 7,520
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pauluk Offline OP
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I have to agree with the comments about farm wiring. I've also seen regular BS1363 outlets and other "indoor" accessories hanging on cables in exposed locations, wires just twisted/taped and strung over the beams, and so on. In fact that goes for outbuildings in general, including domestic sheds, garages, and workshops.

Quote
Sometimes the buildings look like they will come down any minute.
Ain't that the truth!

Here in rural Norfolk there are derelict old farm buildings like this all over the place. Some have been "developed" into vastly over-priced homes. Sure, they have acres of living space inside them when finished and some people have made the interiors very attractive, but they still look as ugly as sin from the outside, IMHO.

I recently saw one of these monstrosities for sale with an asking price of over £100,000 ($160,000). That wasn't the finished article -- Just the unconverted barn in its original (poor) state. [Linked Image]

There are plenty of old barns like this all over the French countryside too, but at much more realistic prices (e.g. only 20% of the above and with ten times as much land).

David,
Quote
I like: TNS & TNC-S systems which are the most prevelant in the UK.
Interesting you say that, as I was going to mention the different earthing systems. I too prefer TN-S or TN-C-S. I've never been keen on the TT system.

I'd agree that TN-S & TN-C-S are the most prevelant in towns, but in this area the majority of rural homes are TT. The whole area network has been converted for TN-C-S, but I see few rural homes which have yet taken advantage of that and earthed to the neutral.

Maybe PME (TN-C-S) was more common years ago in rural areas of the Highlands due to the more rocky ground conditions?

The TT system leads me to the comments from our Canadian friend:
Quote
I have mixed feelings about a whole home RCD, rather than the North American way of using GFCI only where warranted.
That's one of the drawbacks with TT. The high loop impedance means that every circuit needs to be RCD/GFI protected and the cheapest way, of course, it to provide a main RCD for the whole house.

I'd much prefer to see individual North American-style GFI protection where needed in combination with a TN-C-S distribution system.

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