Old colours mixed with new colours

ryanhcafc · Nov 24, 2023

Wouldn't normally note this as an observation on a report but feel I need to. The way the building has been wired is all circuits on L1 have been wired in old red, L2 old Yellow, L3 old blue, however as stuff has been added it's now got new colours. The property is currently empty awaiting new tenants, I've been in today to start an EICR and have already come across 240v between Neutral to earth on 2 of the L3 circuits.
Coding the neutral/live polarity issue obviously but just looking for other people's thoughts on coding the old colours for a lack of identification in regards to live colour? I would always sleeve a black cable with brown if used on a single phase circuit is why I'm thinking this way...
Then I think I'm being over the top but clearly a previous electrician has got neutral and Live mixed up with the blue cable.

thoughts please

westward10 · Nov 24, 2023

Are the "old colours" historic?
Line conductors should always be identified as necessary, pre harmonisation black should be sleeved red and something I still do now.
The 240v between neutral to earth, is it really a neutral?

ryanhcafc · Nov 25, 2023

westward10 said:
Are the "old colours" historic?
Line conductors should always be identified as necessary, pre harmonisation black should be sleeved red and something I still do now.
The 240v between neutral to earth, is it really a neutral?

Should of explained better,

For example lighting circuit installed on 1L2 wired in singles uses yellow as live, black as neutral, green/yellow as earth.
Lighting circuit on 1L3 wired in singles uses blue as live, black as neutral, green/yellow as earth.

So they've used phase colours, however now new cables have been added to the installation someone has got confused at points and mixed blue L3 up with blue on neutrals.

westward10 · Nov 25, 2023

It wasn't uncommon in the 80s for yellow and blue to be used for single phase and without looking this may have been reserved for distribution circuits. For final circuits they should have been tagged red I believe but the fact someone has "confused" them is down to that person's incompetence.

davesparks · Nov 25, 2023

ryanhcafc said:
So they've used phase colours, however now new cables have been added to the installation someone has got confused at points and mixed blue L3 up with blue on neutrals.

Where you have the apparent blue neutral with 230V to earth what colour is the other conductor at that point?

Risteard · Nov 29, 2023

westward10 said:
It wasn't uncommon in the 80s for yellow and blue to be used for single phase and without looking this may have been reserved for distribution circuits. For final circuits they should have been tagged red I believe but the fact someone has "confused" them is down to that person's incompetence.

Yes. My understanding is that it was only permissible on distribution circuits and not final circuits.