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Components and Circuits For discussions about component types, alternatives and availability, circuit configurations and modifications etc. Discussions here should be of a general nature and not about specific sets. |
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7th Oct 2017, 9:17 am | #21 |
Nonode
Join Date: May 2007
Location: Redruth, Cornwall, UK.
Posts: 2,562
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Re: European Black/Blue Mains Lead
Hi.
Regarding flexible cables fitted to portable appliances, I think in Britain we changed over to the new system in about 1970. In the old system, the green earth wire is of a much darker green compared to the later green/yellow code. It also seems to have been the same with earth sleeving used for house wiring. Was that standard practice? I've never seen a mains flex with Red, Black and Green/Yellow wires. Regards Symon |
7th Oct 2017, 9:50 am | #22 |
Banned
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Location: Middlewich, Cheshire, UK. & Winter in the Philippines.
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Re: European Black/Blue Mains Lead
Yes it was standard to have green earths and sleeving.
Red and black always had green earth wire, so did the 3 phase red, blue, & yellow with black neutral and green earth, though 3 phase flex is a bit less common. |
7th Oct 2017, 11:07 am | #23 | |
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Re: European Black/Blue Mains Lead
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7th Oct 2017, 11:19 am | #24 |
Dekatron
Join Date: Nov 2011
Location: Surrey, UK.
Posts: 4,385
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Re: European Black/Blue Mains Lead
Going through (one of) Dad's boxes of "one day" junk the other day, I found a 3m length of same, unfortunately I stripped it for the cores just before I saw this post, otherwise I'd have posted a photo as proof. I've lots of current cable around, I don't like having non-compliant stuff....
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7th Oct 2017, 12:46 pm | #25 |
Nonode
Join Date: Sep 2017
Location: Stockport, Cheshire, UK.
Posts: 2,000
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Re: European Black/Blue Mains Lead
Some old flexes had an earth with just bare copper wire in the outer coating.
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9th Oct 2017, 10:33 am | #26 |
Nonode
Join Date: Jan 2010
Location: North Somerset, UK.
Posts: 2,129
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Re: European Black/Blue Mains Lead
UK split phase supplies are usually at a much higher voltage than those overseas, and DO have a neutral.
230/240 volts between either live and the neutral, with 460/480 volts between the two live conductors. Utilised when only a single phase HV supply is available. Fairly common in rural areas. |
9th Oct 2017, 10:45 am | #27 |
Dekatron
Join Date: Jun 2013
Location: East Sussex, UK.
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Re: European Black/Blue Mains Lead
I think the green/yellow earth conductor came about because people with colour blindness had difficulty distinguishing between red and green. The lighter colours plus the stripe made it easier and safer.
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9th Oct 2017, 12:54 pm | #28 |
Dekatron
Join Date: May 2008
Location: Derby, UK.
Posts: 7,735
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Re: European Black/Blue Mains Lead
Parts of the Continent used to use three-phase supplies but arranged as 127V phase-to-neutral, giving 220V phase-to-phase. So neither pin of a 220V connection would be safe to touch.
I don't think the UK ever used 138V phase-to-neutral / 240V phase-to-phase, but I'm willing to be corrected .....
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9th Oct 2017, 1:07 pm | #29 | |
Nonode
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Re: European Black/Blue Mains Lead
Quote:
Knowing that the stripped wire was the earth could be vital. Interchanging live and neutral seldom mattered much on a portable appliance, remembering that in many countries socket outlets were not polarised. |
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9th Oct 2017, 1:13 pm | #30 | |
Nonode
Join Date: Jan 2010
Location: North Somerset, UK.
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Re: European Black/Blue Mains Lead
Quote:
Some time ago, there was a discussion on these fora about the purpose of a 140 volt tapping on the mains transformer of some vintage appliance, suggesting that somewhere used 138/240. |
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9th Oct 2017, 5:06 pm | #31 |
Retired Dormant Member
Join Date: Dec 2007
Location: Shropshire, UK.
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Re: European Black/Blue Mains Lead
We've just had a H&S bulletin at work detailing a three phase supply fed via a single phase isolator (at another company). Red and blue phases through the switch. Yellow phase sleeved in yellow/green and connected straight through via the earthing terminal
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9th Oct 2017, 7:59 pm | #32 | |
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Re: European Black/Blue Mains Lead
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9th Oct 2017, 8:22 pm | #33 |
Dekatron
Join Date: Jan 2012
Location: Brentwood, Essex, UK.
Posts: 5,316
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Re: European Black/Blue Mains Lead
My late brother-in-law's house in France was originally wired with a three-ohase supply in which green insulated cable was used for the three individual phase conductor connections from the main company fuse to the local distribution boards. There did not seem to be any standardisation in the wiring of the final circuits, which seemed to have all the colours of the rainbow. French installation practice for domestic wiring seems to be to use flexible corrugated plastic conduit with individual wires, and the Bricomarches sell coils of flexible plastic conduit pre-loaded with the appropriate sizes and numbers of conductors.
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9th Oct 2017, 8:30 pm | #34 | |
Nonode
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Re: European Black/Blue Mains Lead
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Chris
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9th Oct 2017, 8:41 pm | #35 | ||
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Re: European Black/Blue Mains Lead
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9th Oct 2017, 9:24 pm | #36 | |
Dekatron
Join Date: May 2008
Location: Derby, UK.
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Re: European Black/Blue Mains Lead
Quote:
Now, obviously a break in the wiring inside the customer's premises can still cause the neutral wire to become live. So I agree the Neutral is not necessarily safe to touch, especially under fault conditions (including cross-wiring from one circuit to another; fine with wire fuses, but replace the consumer unit with one using double-pole MCBs and now you have a situation where the neutral return wire can become live .....) (But that's why you use a neon screwdriver on it, and also on a known live terminal before and after, so you can be sure the neon did not light because the wire isn't live and not because it's faulty, and then approach it cautiously with the outside of your hand so if it is live, your muscles will tense and pull you away. Or whatever modern trendy digital instrument they're using nowadays; neons are so last century .....)
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9th Oct 2017, 9:36 pm | #37 |
Dekatron
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Location: Brentwood, Essex, UK.
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Re: European Black/Blue Mains Lead
Looking back at the photos I took, Red was indeed used for the incoming neutral as per Dutch practice, although for most of the ongoing wiring, White was used.. Blue, Green, and Red were all used for various onward Phase conductors. At least the original installers had written on the conduits where they led to. The house was built in the mid-1960's and subsequently converted to single phase without amending the original wiring, leaving two 3-phase power sockets in situ with all three poles live and connected to the same phase. The wiring was actually installed to a high standard, and in accordance with the then-current French practice, plug-in non-rewirable ceramic cartridge fuses were proved at every light switch and every socket outlet. You had to unscrew the socket or switch to gain access.
A good reason for the use of striped insulation for the earth to avoid ambiguity with legacy continental wiring. Last edited by emeritus; 9th Oct 2017 at 9:42 pm. |
10th Oct 2017, 12:04 am | #38 | ||
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Re: European Black/Blue Mains Lead
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10th Oct 2017, 9:09 pm | #39 |
Nonode
Join Date: Nov 2015
Location: Welwyn Garden City, Hertfordshire, UK.
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Re: European Black/Blue Mains Lead
~2.5mm Blue/Black and plain copper earth?
Go to Norway, Clas Ohlson. It's what they have. In any house of some age, blue and black might be swapped at any socket, the earth wire might be connected through or not. Fun. Start over from the distribution board which was 115/115 + Earth I found out. Fuse in each side. Take out 2 or regret it.... And I almost forgot - later versions have aluminium foil overwrap. That means when you strip it you bleed from a thousand cuts. It's thin but very sharp. Assume it's in contact with earth, good for the hum on pantry transmitters perhaps? Last edited by Jon_G4MDC; 10th Oct 2017 at 9:14 pm. |
10th Oct 2017, 9:50 pm | #40 |
Hexode
Join Date: Jan 2012
Location: Weymouth, Dorset, UK.
Posts: 422
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Re: European Black/Blue Mains Lead
Norway still has some systems of 2wires at 127 volts giving 220 across the 2 with no neutral I think that now they have RCDs they cant wire 127 volt appliance between the un metered phase and a local earth rod which once was common practice.
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