I think i've flipped up
I was under the impression we use the Brown Blue and Green/Yellow help with colour blindness (most common green and red)
I know it's to bring UK in line with EU. But why did EU use them colours.
Because I understand green earth (CPC)
Red Live (line) [hot colour]
(Forgive any misspellings Dyslexic and hard to see , also miss out works as forget to type them)
Even in the UK there's been right mess of colour codes over the years- e.g. see https://electrical.theiet.org/wiring-matters/years/2021/84-march-2021/the-history-of-colour-identification-of-conductors/ and our continental cousins hadn't really got the harmonized thing properly sorted until recently either (L was typically brown or black, but which indicated L1, L2 or L3 was still a bit random) see - https://electrical.theiet.org/media/1720/harmonised-colours-and-alphanumeric-marketing.pdf
Little surprise then that the recent introductions have picked much less common colours (e.g. grey and pink).
I think the modern colour codes actually come from IEC (i.e. worldwide) standardization, and merely adopted by CENELEC (not the EU) so have had to consider American and other practice too (e.g. white for N to match the tin plating they put on N terminals for identification).
- Andy.
Even in the UK there's been right mess of colour codes over the years- e.g. see https://electrical.theiet.org/wiring-matters/years/2021/84-march-2021/the-history-of-colour-identification-of-conductors/ and our continental cousins hadn't really got the harmonized thing properly sorted until recently either (L was typically brown or black, but which indicated L1, L2 or L3 was still a bit random) see - https://electrical.theiet.org/media/1720/harmonised-colours-and-alphanumeric-marketing.pdf
Little surprise then that the recent introductions have picked much less common colours (e.g. grey and pink).
I think the modern colour codes actually come from IEC (i.e. worldwide) standardization, and merely adopted by CENELEC (not the EU) so have had to consider American and other practice too (e.g. white for N to match the tin plating they put on N terminals for identification).
- Andy.
The great merit of green/yellow striped for earth is that it is obvious even to someone with defective colour vision that the striped one is the earth.
Normal colour vision is a requirement for performing most types most types of electrical installation work, however a colour blind householder might need to wire a plug.
Knowing that the striped wire is the earth is a potential lifesaver in such circumstances. Confusing the live and neutral does not much matter when wiring a plug. Remember that many countries use reversible plugs and sockets, so polarity at a portable appliance is random, and no one worries.
"Normal colour vision is a requirement for performing most types most types of electrical installation work" Why then is a colour blindness test (or even a question about it) not a requirement under the various schemes?
PS there are plenty of colour blind electricians
Complete inability to perceive colour is rare. Red/green is the commonest type, so that shouldn't be a problem with reasonably modern installations. Even then, it should be obvious whether a conductor is line or earth fron the way that it is connected.
Colour-blindness isn't exactly going to make any difference with grey and black conductors.
Would-be Royal Navy engineers who fail the normal tests have to undertake trade tests to demonstrate that they will be able to identify what they need to.
Also, to add to the history, a change was made to the identification colours for L+ and L- conductors for DC systems, and also to the identification for FE (functional earthing) conductors. The latter was explicit in Corrigendum:2018 (the former inferred by implying an implementation date for BS EN 60445 in the Corrigendum also). The Draft for Public Comment for Amendment 2 to BS 7671:2018 saw these changes in Table 51 itself. Further information in this article: https://electrical.theiet.org/wiring-matters/years/2020/83-november-2020/section-514-identification-and-notices-in-the-amendment-no-2-draft-for-public-comment/
The small label for surfaces <10cm² is a curious one - since the label itself appears to be 12.5cm² (5cm wide x 2.5cm high).
- Andy.
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