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February 23, 2017, 07:01:41 AM *
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Author Topic: Intercity Express Programme (IEP) - ongoing discussion  (Read 272287 times)
IndustryInsider
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« Reply #900 on: February 17, 2017, 02:49:46 PM »

I think they're designed to be seen at a distance so people will be able to scan and locate them quicker, helping to reduce the bunching that currently happens when passengers slowly shuffle down the carriage looking at each seat separately.
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stuving
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« Reply #901 on: February 17, 2017, 04:30:22 PM »

Red green colour blindness is why the British electric wiring (flex) colours were changed in the 1970s from red-black-green for live-neutral-earth to brown-blue-green/yellow(stripe). Imagine mixing earth and live up in a plug!  Shocked

Fixed wiring changed to suit just a decade ago and is now a European standard.

I think the choice of a spiral stripe on the earth wire was to make that identifiable with limited colour vision, but not the rest of the colours. That new earth colour may even have been introduced here before the other changes.

I think I can see the logic of all the colours chosen, based on the idea that the main objective is to ensure the earth wire (and so the casing) gets connected to earth (this was before built-on plugs).  Provided the right wire is connected to earth, which wire inside the device is live and which is neutral should not matter. So the new earth colour should be right in as many countries as possible (hence green, I think) plus its helpful stripe. The other two colours must not be used for the earth anywhere, or else someone might reason (as I just did) that that one must be earthed and the other two don't matter.

Both black and read were earth colours (red in Germany), and light blue wasn't - I think the French may have already picked that for neutral.  I've always been surprised that brown wasn't used for earth somewhere, and I've just heard it was - in Britain, pre-war. But there were so many systems in use then, that I think only the national standards were considered.

The European agreement to change the colours for appliance leads was made as long ago as 1968, so before the UK joined the EEC. Its implementation was spread over the next ten years, so it overlapped with our EEC membership. The reason was of course to support a "single market" in appliances (still long before the European Single Market), while removing the obvious hazards.
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broadgage
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« Reply #902 on: February 17, 2017, 05:15:23 PM »

The green yellow striped core for earth was indeed introduced so that persons with poor colour vision could recognise the earth.
There was a transition period when green/yellow for earth coincided with red and black for live and neutral.

Those with significantly defective colour vision should not be working on the fixed electrical wiring of a building, but may need to safely wire a plug, especially before virtually all appliances came with a fitted plug.
Interchanging live and earth could have disastrous consequences, confusing live and neutral does not really matter for a portable appliance.
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"When customers say that they want a seat, they dont mean they want to sit with their knees behind their ears so that 4 more can sit down. They mean that they want an extra coach so that 74 more can sit down"
"Capacity on intercity routes should be about number of vehicles, not compressing people"
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« Reply #903 on: February 17, 2017, 05:18:41 PM »

Electrical Appliance (Colour Code) Regulations 1969, statutory instrument No. 310 was what changed UK appliance wiring, although there was a transition period.

As has been mentioned old German appliance flex wiring colours had red for the earth and there could be a rather 'spectacular' effect if this was mistakenly wired to the live in the UK.
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Surrey 455
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« Reply #904 on: February 17, 2017, 11:08:26 PM »

Many years ago my dad taught me how to wire a plug. The first two letters of blue are BL which stands for Bottom Left and the first two letters of brown are BR which stands for Bottom Right. The other wire (green / yellow) if it is there, obviously goes in the one remaining pin.
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bignosemac
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« Reply #905 on: February 18, 2017, 02:04:38 AM »

Wiring a plug is no longer routinely taught in schools. I remember it was one of the first things I was taught in science lessons as an 11 year old in my first year of Secondary School in 1984.

I guess the reason it is no longer routinely taught is that, by law since 1994, all 13A or less appliances running off the domestic mains supply must be sold with a plug already fitted.

The only appliances I've wired to the mains in recent years are electric cookers to their dedicated circuit.

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