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The Frustrations of Electricity Around the Globe

Posted January 28, 2010 7:00 PM by PWSlack

Engineers and designers need to develop long-distance strategic thinking if their designs are going to last and have global appeal. Another area where this hasn't happened is electricity supply.

1 - voltage

230V, 220V or 110V? There is some compatibility between the first two, as the voltage tolerances overlap. A piece of equipment bought in France will work in the UK, though it might not last as long as was intended due to the marginally higher voltage in use there. It will probably not work at all when plugged-in in Canada, even if the instructions are in French.

Many US-based electric shavers have suffered irreparable damage when inadvertently plugged into the outlet in a European hotel without the voltage being switched…

2 – frequency

Often in this site a question is asked along the lines of "My appliance is 50Hz. Can I use it on a 60Hz supply?" If the item has some motor function, or is reliant on the supply frequency for some timing function the answer is "not without some interposing device that can change the frequency of the electricity being supplied". The equipment will run either too fast or too slow, and that will have an affect on the both current it consumes and the function it provides, particularly if it is a motor. A circuit protective device may operate and disconnect the equipment on one frequency whereas on the other one it may be perfectly comfortable. If it has a clock pulse derived from the mains frequency, then it may show the incorrect time by a rate variation of +20% or nearly -17%.

3 – power sockets

There are upwards of 14 types of domestic power plug and socket in use across the globe and a number of obsolete types may be found occasionally in addition to them. Most of these types are not readily interchangeable. Anyone who has ever gone through an international airport will have noticed the plethora of power adaptors available for the traveller to buy; that pan-European adaptor in the hold baggage is of no value in the Americas or in Australia/New Zealand, for example.

4 – wiring styles

One peculiarity to UK-derived wiring standards is the domestic 30A fuse- or 32A breaker-protected "ring main". Developed after the 1939-1945 global conflict as a cheaper way to wire new and rebuilt houses (owing to the high value of copper at that time) its use has persisted to the present day. The principle is, rather than send out cables radially from the distribution board to each socket as would have happened pre-war, a ring of smaller-cross-section copper cable is linked to the circuit protective device and any number of 13A sockets connected to the ring. Each appliance connected to the ring is then protected by a fuse in the plug. The system uses less copper than the earlier radial arrangement for the supply of the same amount of power. With electrical labour becoming pan-European, non-UK electricians may be unfamiliar with the ring-main concept and may not fully appreciate the need for more rigorous testing before the issue of the Installation Certificate, potentially putting the householder as well as themselves at greater risk.

"Wiring colours have been harmonised across the European Union." For new installations, yes, though not for add-ons to pre-2006 installations. Before, the blue wire was either one of the three phase colours or one of the two switched-live conductors in a 2-way lighting circuit. Today it's the new neutral. Before, the black wire was the neutral. Today it is either one of the three phase colours or one of the two switched-live conductors in a 2-way lighting circuit. The usual British Compromise applies: stick a warning label on the fuse board…

5 – Synchronisation

The UK's grid and the French grid have been interconnected for some time. As demand and availability change in each nation, power flows backwards and forwards between the two countries in an attempt to stabilise supply. The problem is that French 50Hz is not synchronised to UK 50Hz, so the link between the countries is a high voltage DC one, with the power converted to match each country's grid at each end of the link.

Aggravating, isn't it?

Resources:

http://en.wikipedia.org/wiki/Domestic_AC_power_plugs_and_sockets

http://en.wikipedia.org/wiki/Mains_power_around_the_world

http://en.wikipedia.org/wiki/Electrical_wiring#Color_code

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Guru

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#1

Re: The frustrations of electricity around the globe.

01/28/2010 9:51 PM

Thanks for putting this up. I'll look at the referenced links to see if I see a picture of a ring main. I've never seen one.

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Commentator

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#2

Re: The Frustrations of Electricity Around the Globe

01/29/2010 4:56 PM

Not only is it aggravating it's bad for business also. I once had to connect telephone cable (Euro) with US made cable that we got just because the Iron Curtain fell and no Euro cable was for sale. What a nightmare, the cable comes in pairs of 3 while euro cable comes in pair of 4. Once the supply issue was solved we jumped back to purchasing euro style cables as that was 99 % of our network. All US business was avoided just because of this mismatch. Business that could have been ours went overseas because we can't get our head around the metric system. If the economy looks blurry now, well think what it will look like in a couple of years. The Chinese don't care what system we use. They'll make it and to anyones specs.

Why is that so hard for American manufacturing....

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Anonymous Poster
#3
In reply to #2

Re: The Frustrations of Electricity Around the Globe

01/29/2010 10:41 PM

Hi. I've got a bunch of long-lost cousins in Newtown Square. Know any of the Stidhams? Best regards,

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#4

Re: The Frustrations of Electricity Around the Globe

01/29/2010 11:10 PM

I have been seeing a lot of newer electronic equipment being labeled, "95-240 V AC, 50-60 Hz" suggesting that at least someone in China is aware of this issue...I am still waiting for the first motor to meet these specs...

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#5

Re: The Frustrations of Electricity Around the Globe

01/30/2010 4:52 AM

Compatibility is always an issue...don't get me started on HDTV, Vido players and phone charger...
Oh, yes ...phone chargers are to have a common standard plug, due to come in when hell freezes over.
Del

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#6

Re: The Frustrations of Electricity Around the Globe

01/30/2010 9:15 AM

Thanks for posting this and hopefully having something click with manufacturers and specifying engineers

Though becoming rare, I still find confusion occasionally when I am called to witness a FAT or review design documents.

I have seen equipment designed for 50Hz trying to be tested with some 60 Hz equipment and I question this always.

Am I being unrealistic, as I have been told, our am I questioning a test that may not meet the parameters of design considerations?

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Anonymous Poster
#7

Re: The Frustrations of Electricity Around the Globe

01/30/2010 2:04 PM

Running 50Hz transformers and rectifiers from 60Hz supplies is generally OK - so long as there is nothing in the load that utilises the supply frequency. 60Hz equipment on 50Hz supplies can be another matter - it takes more core material for a given power at 50Hz, and diode-capacitor rectifiers can start to hum. Even systems using inverter-based voltage transformers may not be immune to the second problem.

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#8

Re: The Frustrations of Electricity Around the Globe

01/31/2010 8:46 PM

Thoroughly agree on all these points, but there is a reason in all this madness. Incompatible electrical supplies make big corporations sleep well at night, at the thought of selling you the same product allover again.

"Oh my gosh" says Big Products R Us CEO Ivor Belly. "We have sold our customers everything they need!"

"But ve have zee cunning plan." says Big Products R Us Marketing Dept Head Slime E. Ratt. "Ve note that all ze voltages are veeery different. Ve vill make ze products incompatible and force ze customers to buy new kit!"

"It will never work!" says Ivor. "Our customers are too smart! They will see through such obvious trickery!"

"No!" says Slime. "Ve vill make only the slightest of changes! Zen ve vill design a non-standard cable vith vitch to connect to ze electricity! Ve vill charge 10's of times more vor zis cable than z product! They will be conned vor sure!"

"Make it zo!" says Ivor, who succumbs to the accent also.

I campaigned long and hard for the UK to rid itself of the ridiculous and dangerous ring system. Hasn't happened yet.

By the by, the DC link between France and UK is not DC because the mains are synched, but becuase it has to be for an undersea cable to work efficiently.

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Anonymous Poster
#9
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Re: The Frustrations of Electricity Around the Globe

02/01/2010 10:48 AM

"ridiculous and dangerous ring system"

I don't suppose that you are comparing with one cable per socket, as this really is ridiculously expensive, both in terms of wire routing difficulty and cable cost.

So it must be a comparison against pure-radial systems?

The ring relies precisely on the same diversity that makes multi-outlet radial systems possible. It is effectively two spurs with the ends joined. Where the target area is small it can allow reduction of copper usage compared with alternatives and easier routing; this is due to the same "diversity" that makes multi-outlet spurs possible. Note that there is minimal or no advantage if either the target area or the distance to the target area is large.

In spite of the theoretical risks, the incidence of ring-induced events is very small. This is at least in part due to the de-rating of the system to allow for asymmetric loading. Nevertheless, I would support proposals for a modified standard for the ring main for future installations. The modification would be to treat the two ends of ring as separate circuits, each to include low-sensitivity (perhaps a sense-current of about 0.5-Amp) RCDs. The advantages of such a system are both that it would allow fuller exploitation of the cable capacity, and also that it would minimise the stray field that broken and high-resistance links might cause.

Of course, other than providing the appropriate fused plug, this has no impact on the "global frustration" issue. Individually fused plugs or sockets should of course be mandatory in any system where the distribution fuse exceeds the individual device rating. I find their absence in some jurisdictions to be of far greater concern, given that this has demonstrably caused far more and more serious adverse events than problems with incorrectly-installed or damaged rings.

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