Replacing old downlights

[Jmsmcln]

Down to two lights working now so planning to get this sorted pretty soon.

I've been up to the loft again and there's 3 transformers each powering 3 downlights.

What's confusing me now is that there's 2 twin and earth feeding a choc block which outputs live and neutral to the 3 transformers. The two live cables coming in go off to a separate choc block and end there, as do the earths. Then the two black neutral cables feed the choc block for the transformers.

Can anyone explain what's going on here? Has the electrician just used whatever colours he felt like? The light switch has a blue sleeve over the earth as well.

Thanks all

 

[winston1]

The 2 black cables are not both neutrals. Cables don’t know what colour they are. (For the pendants I know black is not a colour). One of them is a switched live.

 

[Jmsmcln]

The 2 black cables are not both neutrals. Cables don’t know what colour they are. (For the pendants I know black is not a colour). One of them is a switched live.

I'm just confused as to why the switched live would end up being black. Isn't that bad practice?

Do I just leave it as it is?

Final question - are the choc blocks OK or should I replace with a modern connector?

Cheers

 

[plugwash]

Normal twin and earth cable has one core in the live color (red on older cable, brown on newer cable) and one core in the neutral color (black on older cable, blue on newer cable).

When normal twin and earth cable is used for a switch drop (which has a permanent live and a switched live but no neutral), sleeving (red on older installs, brown on newer) should be used to mark the switched live conductor as such, but this is often omitted by lazy installers.

Terminal block is ok if it's inside a suitable enclosure and is accessible for inspection. It is not fine to have it just floating free like that.

 

[EFLImpudence]

Normal ceiling rose arrangement - without ceiling rose.

https://www.diynot.com/wiki/Electrics:Lighting-Circuit-layouts

 

[winston1]

Normal twin and earth cable has one core in the live color (red on older cable, brown on newer cable) and one cable in the neutral color

It is colour in the civilised world.

I personally think that using black or blue for switched live is silly, but that is the way it is. In some countries, France is one, switched lives are orange, and violet if there is a second one as in two way switching. But they always use singles in conduit rather than twin and earth.

 

[Jmsmcln]

Thanks for clearing that up.

Can I just ask what is the best way to take earth from this set up to the first light?

 

[Risteard]

Sensible countries use twin brown for domestic switch drops.

 

[winston1]

Sensible countries use twin brown for domestic switch drops.

No that is a silly idea as well. It is sensible to identify the switched live, as in France, Switzerland, and Australia to name a few.

 

[securespark]

Winston.

Make your mind up.

You say blue/black is a bad idea and twin brown/red cable is bad too.

Using twin sheathed cable (as we do in this country, never mind France), how would you ID the switched lives, except at termination points?

You could ID the switched lives at termination points without any conductor marking or colouring.

Twin brown (or red as it was) is perfectly acceptable. All these kinds of cables I have ever installed have been marked in some way to show a difference between them. Some have a ridge down one conductor's insulation, others have the colour of the insulation all the way through on one conductor and only on the outside on the other.

 

[winston1]

My mind is made up. Black/blue, twin red and twin brown are all bad ideas but we are stuck with them. I believe switched lives should be identified with a separate colour, orange or violet in France/Switzerland, white in Australia pre harmonisation days (not sure what is used now).

T & E could be manufactured with brown/orange for switch drops just as easily as twin brown which would become obsolete. Triple and earth for 2 way strappers could be brown/orange/violet plus earth.

I suppose the colour blindless lobby would have something to say, wonder what they say in F, CH, and AUS.

 

[securespark]

But we are not in F CH or AUS.......

 

[winston1]

But we are not in F CH or AUS.......

Indeed, but there is no reason not to adopt their standards if they are an improvement on ours.

Interestingly those three countries all use (different) polarised plug/sockets different to the non polarised types used elsewhere in much of Europe.

 

[securespark]

Indeed, but there is no reason not to adopt their standards if they are an improvement on ours.

Feel free to lobby the IET....
In the meantime?

 

[securespark]

(For the pendants I know black is not a colour).

I hate to be a pendant, but.....