Wall light 3 core cable with no earth

[ebee]

Actually, whilst I was ok with Green for Earth I am more than happy for it to be Green/Yellow. It’s the Ls an N changes I am not too happy about

 

[Harry Bloomfield]

Actually, whilst I was ok with Green for Earth I am more than happy for it to be Green/Yellow. It’s the Ls an N changes I am not too happy about

The only benefit I've seen from the change, was that it left red and black, to identify positive and negative of a DC supply.

 

[SUNRAY]

Wire colours are arbitrary decisions without any absolute rationale behind them. The only rational arguments are to use a colour combination for earth that can be recognised even by people with any known type of colour blindness and not to use colours that can be confused easily in poor lighting conditions for very different purposes (e.g. L and N).

That makes a lot of sense and the idea of a striped cable to make it different is a brilliant idea, so why did they stupidly chose yellow and green which sit beside each other on the colour spectrum and the stripes frequently disappear under some very ordinary lighting.

The current UK colours are the result of over five decades of international negotiation and used throughout Europe as well as in a number of countries outside Europe but there's nothing inherently good or bad about them other than what I mentioned above.

I beg to differ on that, the colours chosen are crap! working in control panels as I do there are tens, hundred, even thousands of wires and frequently it is impossible to idendify the colours where a brown is a darker black than a black. or a black is a lighter colour than a darker grey or the pale blue is more washed out than some greys etc.
That simply never happened with our sensible selection of colours. It would have been so much better if they had gone with another proposals of brown, black, white, blue which (if I understand it correctly) had more votes than grey.

 

[SUNRAY]

The only benefit I've seen from the change, was that it left red and black, to identify positive and negative of a DC supply.

Which is incorrect.

I believe it has changed since but at (before)harmonisation it became +ve = (red)brown, -ve = (blue)grey, 0v(earth or chassis)/midpoint = (black)blue

A little while ago, I believe it was on this forum someone indicated it's now red, white, (and I think)blue which happens to be our 60's 3phase colours.

 

[robinbanks]

Aye, quite a lot of control logic got done by relays years ago

If you think about it, a CPU is but millions of relays and valves

 

[ebee]

Yes absolutely. A few years back I was doing multiple zone heating and HW for boiler heating systems via hardwiring stats and valves and the plumbing/heating bods were describing to me how each particular system was required to work, sometimes I would devise a little electronic circuit or ready available timers to suit their particular application. Customising I enjoyed immensely putting in little quirks and “one shot” buttons to start a little particular sequence off. Suppose one might equate it these days to little programs or Apps. Anyway good fun.