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#137576 07/16/03 05:11 PM
Joined: Aug 2001
Posts: 7,520
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pauluk Offline OP
Member
We've been talking about the way that a forum such as ECN allows those of us from diverse countries to exchange ideas and information on our respective wiring systems.

So let's get down to some cases:

Is there anything (be it the design of a device, a circuit arrangement, or whatever) from another country which you think is a great idea and would like to see adopted in your own country?

Conversely, is there anything about a foreign system which you definitely do not like and would not like to see adopted at any cost?

#137577 07/17/03 04:33 AM
Joined: Sep 2002
Posts: 1,498
Likes: 1
C
C-H Offline
Member
I like that the British and Americans have used protective earth throughout the entire system for decades. I dislike the Swedish idea of sticking to ungrounded sockets.

I like the Belgian use of 20A radials instead of our 10A radials.

I like the Belgian and Irish systems with 40A or 63A single phase rather than our 16A 3-phase. (32A 3-phase would have been even better. [Linked Image] ) I don't see the point in the oversize British 100A single phase service.

I don't see the point in the British fear of 3-phase, but at the same time I don't like the Swedish overuse of it. Today we need to get a fan in the office running. It's 3-phase, but only 100W, with separate control gear (which has failed). A 230V plug and a built in pull cord switch would have worked just as well, and been a lot cheaper to fix.

[This message has been edited by C-H (edited 07-17-2003).]

#137578 07/17/03 06:55 AM
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Posts: 7,520
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pauluk Offline OP
Member
I have to agree there. Granted, 3-phase motors run smoothly and efficiently, but for only 100W it seems rather ridiculous.

#137579 07/17/03 10:37 AM
Joined: Dec 2001
Posts: 2,498
T
Member
100W 3ph fan is ridiculous. I think the German way - <3600W -> 1ph, >3600W -> 3ph is quite reasonable. I absolutely hate the thought of running 4 or 6mm2 wires to cookers, 5x2.5 is far easier to work with. 20A radials are a bit too hefty for my liking, 13 or 16A is quite ok. Again we'd need 4mm2 for 20A according to our regs. Ring circuits are far too complex to be safe with all the botching going on, even by licensed pros.
Schuko plugs have a good and a bad side. On the plus side, they won't ever fall out of the receptacle, they're safe because they're recessed, and if you're used to them they don't even look bad.
On the minus side, I recently nearly broke my arm trying to pull out a plug behind my desk. The receptacle is rather new and very strong, so it sometimes takes a lot of force to get out. I've seen more than one surface-mount Schuko receptacle hanging by the wires.

#137580 07/17/03 01:21 PM
Joined: Oct 2002
Posts: 177
B
Member
I find the ring circuits ridiculous. I never appreciated Belgian electricity systems, untill I met all of you in this forum! We have standard a minimum of 40A monophase and we can easily get up to 400V 3 phase 40A.
A note abbout 20A radials: 20A can only be used with 2.5 mm2 and with a MCB. A fuse would be 16A.

Personaly I would have appreciated better a TN system than a TT system.

#137581 07/17/03 02:26 PM
Joined: Jul 2002
Posts: 8,443
Likes: 3
Member
I'm not too keen on the US practice of having sockets with no switches on them.
Sure, you can simply pull the plug-top out, but if there was a reasonably heavy load on the socket, wouldn't this damage the socket contacts after this was done a few times?. [Linked Image]

#137582 07/17/03 08:31 PM
Joined: Apr 2002
Posts: 2,527
B
Moderator
OK I gotta’ toss in some comments about 1ø versus 3ø motors. Appliances like slab- or roof-mounted air-conditioning units, usually contain ‘capacitor-run’ motors, often called PSC {permanent split-capacitor} devices. Like capacitor-start motors, PSC motors have main and auxiliary windings of two different copper gauges. The problem is that the smaller gauge conductor has less thermal mass, and is more prone to failure, regardless of protection method used. Bearing wear, short-term undervoltage, capacitor failure or mechanical overload seem to be able to cook windings in very short order.

In 3ø motors, windings are symmetrical—evening out the stress on winding insulation, making them easier to protect from insulation failure.

In the past, for hermetic and semi-hermetic compressors, the comparative “burnout” failure rate of 1ø versus 3ø has typically been nothing short of extreme…

#137583 07/18/03 05:32 AM
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pauluk Offline OP
Member
Well, we're getting some interesting points raised here.

On the 1-ph vs. 3-ph argument, I certainly don't see the point of running 3-ph residential supplies fused at just 16A per phase. It seems to be an unnecessarily complex way of providing a comparatively small amount of power, and results in problems of how to connect heavier appliances for proper distribution of load between phases.

I'm quite happy with the British use of 100A single-phase services though. Adopting a policy of, say, single-phase up to 60A then go to 3-phase wouldn't be too much of a problem in towns and villages where a 4-wire wye network is already running along the street, but it would be a different matter in many rural areas.

At present, an odd couple of houses out on their own are fed with a 1-ph transformer from a two-leg HV spur. If more remote homes such as these had to be wired 3-phase the provision of a 3-wire HV span and 3-ph xfmr bank would likely increase installation
costs considerably.

I think that by now you're all aware that I agree with you entirely about the ring circuit. [Linked Image] Not that I can imagine any other country even considering its adoption....

Quote
I'm not too keen on the US practice of having sockets with no switches on them.
Not just the U.S., but all of Continental Europe and much of the rest of the world as well. Switched receptacles seem to be a very British/Commonwealth thing (Canada excluded).

While we're on the subject of switches, I really wish Britain could have been consistent in its orientation of switches. Depending upon age and make, the main switch on panels can be up=on or down=on. Modern MCBs, RCDs, and main switches are all up=on, but light switches (and other wall mounted switches, e.g. ranges) still adhere to the convention of down=on. Let's get everything working the same way. My vote is for up=on.

Scott,
I hadn't thought about the problems with split-capacitor motors, but then air-con and the like isn't very common here except in big commercial applications. In the majority of houses in Britain (and indeed in most of northern Europe I would think) the most powerful motors to be found are those in a washing machine and refrigerator compressor.

#137584 07/18/03 01:49 PM
Joined: Sep 2002
Posts: 1,498
Likes: 1
C
C-H Offline
Member
Paul,
how would you run a farm without 3-ph ? Perhaps not all homes in the countryside are farms in Britain?

One drawback of 3-ph is that you need a big panel, with all those 3-pole MCBs. One 3 pole MCB for the cooker, one for the heat pump, one for the pool pump, one for the ventilation system, one for the general purpose socket. Not forgetting the 4 pole RCD. It fills the panel in no time.


Cooker, panel, MCB... My English is somewhere in the middle of the Atlantic. [Linked Image]

#137585 07/18/03 05:01 PM
Joined: Aug 2001
Posts: 7,520
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pauluk Offline OP
Member
There are most certainly plenty of homes in the British countryside which are not farms. The 4-wire 3-ph wye system (with 2-wire 240V taps for each house) is common anywhere where there is a group of houses, but for odd houses out on their own a single-phase transformer is often employed.

Here's a typical 1-ph pole-mount xfmr fed from a two-wire 11kV spur:
[Linked Image]
This particular one is located about a half-mile outside of town (Stalham, pop. approx. 3000) and feeds a pair of houses.

You might remember the can-type transformer in this thread . The area in which this was located has several two-wire 11kV spurs, each running for maybe a quarter to a half-mile to feed odd homes.

Quote
My English is somewhere in the middle of the Atlantic.
So is mine! I started talking about the grounded conductor the other day and then realized from the blank looks that nobody knew what I meant! [Linked Image]

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