Replacing light - House that jack built!

[AnnaA1982]

Hi All

Bit of advice please.

Just bought a new light fitting for a bedroom but just want to make sure im wiring it correctly.

Old ceiling rose has 2 - Cables (2 red,2 Black, 2 earth) I presume this is the last light on the loop.

New fitting has block with space for L E N & spare at the end.

Unsuprisingly for my house there is no mark on the cable for switch live - So having traced the cable through the loft ive identified which cable is going to the switch and the black wire is in the Com port in the switch. Am i correct in saying this is therefore the switch live?

New fitting would be as follows then..

Black from switch cable in L port
Black from circuit in N port
2 Green/Yellow in E port
2 remaining reds in spare to link loop.

Many thanks

 

[AndyPRK]

that's correct.

And I assume its like that now too.

 

[AnnaA1982]

Thanks for the quick response!

Ashamed to say i disconnected old wiring without making note of connections


Crawling through the loft following the cables has reminded me not to do that again!

 

[AnnaA1982]

Just out of interest.. as its the end of the circuit would it matter which of the black or red wires i connect to the L terminal on the light fitting?

Black & red are both technically live from a switch anyway are they not? So either way would complete the circuit.

 

[AndyPRK]

That is correct however as you have gone to the trouble, may as well connect correctly.

With lamps/bulbs with screw fittings its best to get the live wire into the correct position.

 

[conny]

Just out of interest.. as its the end of the circuit would it matter which of the black or red wires i connect to the L terminal on the light fitting?

Black & red are both technically live from a switch anyway are they not? So either way would complete the circuit.

Yes it would complete the circuit but 'Good Practice' is to terminate both reds in the 'spare' block and place a short brown sleeve on the black switch wire to identify it as such.

 

[securespark]

Just a foot note for anybody who may come across this in the future who is confused.

When you said "which of the red wires" you must have meant "which of the black wires" as the red wires are the permanent live in and out to the switch and connecting this to the L terminal on the light fitting would have left your light on all the time!

Whereas, of the two black wires, one will be live when the switch is closed (and as conny says should be ID'd) and the other will be the neutral.

Also, don't forget to sleeve the earth wires.

 

[conny]

SS I think what the O/P was trying to say was if he connected the black from the switch to the red from the feed and then the red from the switch to the lamp it would still work. Which is right but not the correct way as it may confuse someone to see a black and red in the same connector block.

 

[JohnW2]

...and place a short brown sleeve on the black switch wire to identify it as such.

I have to say that I'm not one for mixing 'old' and 'new' colours on the same cable/conductor - I'd be more inclined to put red (rather than brown) sleeving on a black!

Kind Regards, John

 

[conny]

Quite right John but red or brown would signify it was a live cable.

(Why the hell we had to change just to suit Europe is beyond me. We are an independent island and should have told them to get stuffed.)

 

[JohnW2]

Quite right John but red or brown would signify it was a live cable. (Why the hell we had to change just to suit Europe is beyond me. We are an independent island and should have told them to get stuffed.)

I have a lot of sympathy with that viewpoint but, apart from the fact that it's a fait accomplis, I suppose the large-scale international movement of people makes it desirable to have as much standardisation as possible.

I'm more concerned about the choice of brown ('by them') in the first place. Red is an almost universal (global) indicator of 'danger', whereas brown is quite the opposite, and 'orribly like the colour of 'the earth'!

Kind Regards, John

 

[ban-all-sheds]

Why the hell we had to change just to suit Europe is beyond me

That does not surprise me.

We are an independent island and should have told them to get stuffed.

We are an island which is part of Europe. Look at a map or a globe and stop being so ignorant and pathetic.

 

[Astra99]

Yes, BAS, I agree, we are a European island. But that is as far as it goes.

The European "standard", the German Schuko plug, can be inserted either way up. Is that "better" than the British BS1363?

The only thing protecting the flex in Europe is the 15A fuse or 16A breaker. If the cable is 0.5mm² then it will get a "bit 'ot". The common BS1362 fuses are 3A, 5A and 13A. Which offers a greater degree of protection?

Can of worms really and truly opened, and no apologies whatsoever!

 

[stillp]

Quite right John but red or brown would signify it was a live cable. (Why the hell we had to change just to suit Europe is beyond me. We are an independent island and should have told them to get stuffed.)

I have a lot of sympathy with that viewpoint but, apart from the fact that it's a fait accomplis, I suppose the large-scale international movement of people makes it desirable to have as much standardisation as possible.

I'm more concerned about the choice of brown ('by them') in the first place. Red is an almost universal (global) indicator of 'danger', whereas brown is quite the opposite, and 'orribly like the colour of 'the earth'!

Kind Regards, John

Remeber John, about 10% of Caucasian adult males have some degree of colour-blindness.
Also it is not only the line conductor af a single-phase system that is hazardous.
The choice of brown was the result of an international consensus, in which the UK participated.

 

[JohnW2]

Remeber John, about 10% of Caucasian adult males have some degree of colour-blindness.

Colour blindness obviously isn't restricted to Caucasians, males and certainly not adults (it's usually present from birth), but I presume you are talking about the most common, 'sex-linked', form of red-green colour blindness - and, yes, that is obviously a consideration

The choice of brown was the result of an international consensus, in which the UK participated.

I don't doubt that a lot of thought, discussion and 'science' went into the choice, but I'm still surprised by what they came up with. I'm presumably wrong, but I'm surprised to hear (the implication) that blue/brown discrimination is easier than red/black discrimination for those with red-green colour blindness

Also it is not only the line conductor af a single-phase system that is hazardous.

Yes, it gets more complicated when one moves to 3-phase, and I hadn't really thought too much about that - it's 'brown=live' that I most worry goes against the intuition of a lot of people (with normal colour vision!) - but I have to say that I do wonder about brown/black/grey (and the distinction from blue) for those with defective colour vision, as well as the 'intuitive problem' of brown and black for line conductors (in those with normal colour vision).

I suppose this all goes to show that my gut feelings are probably wrong!

Kind Regards, John