Sleeving Brn-Blk-Gry cores for SP. Is there a convention?

[Mark42]

If using 3-core SWA Brown/Black/Grey for a single-phase circuit, what colours do you use?

I leave the brown as live, then sleeve the black with blue for N and the grey with grn/yel for E.

It's arbitrary, but was wondering if there's an informal convention, and if maybe I've been 'doing it wrong' for twenty years?

 

[Mark42]

And here's another thing: when wiring a single phase circuit from a TP DB might one sometimes ignore convention, and 'export' the phase on the 'correct' line colour? (L1 brn / L2 blk / L3 gry).

It's sometimes useful to immediately know which phase is present at the far end, without testing or referring to (lost!) documentation.

 

[Deleted member 26818]

And here's another thing: when wiring a single phase circuit from a TP DB might one sometimes ignore convention, and 'export' the phase on the 'correct' line colour? (L1 brn / L2 blk / L3 gry).

It's sometimes useful to immediately know which phase is present at the far end, without testing or referring to (lost!) documentation.

That’s been prohibited by the Regs for some time now.
I believe it was allowed for distribution circuits up until either the 16th or 17th.

 

[Mark42]

That’s been prohibited by the Regs for some time now.
I believe it was allowed for distribution circuits up until either the 16th or 17th.

Oops! I admit I didn't know that! I'm 17th Ed'n and a bit out-of-date.

I'm puzzled why it should be absolutely prohibited though: brn, blk, and gry are clearly legit phase colours, so as long as the remaining two are clearly sleeved blu & grn/yel at both ends, where's the danger?

 

[Deleted member 26818]

Oops! I admit I didn't know that! I'm 17th Ed'n and a bit out-of-date.

I'm puzzled why it should be absolutely prohibited though: brn, blk, and gry are clearly legit phase colours, so as long as the remaining two are clearly sleeved blu & grn/yel at both ends, where's the danger?

I don’t know?
When I worked at Tate and Lyle, we used to use the phase colours for all circuits.
I dread to think what the trunking will look like now Black is a phase colour.

 

[GBDamo]

Tin hat on but, I tend to maintain the convention already being used in the installation.

It pains me but I think having two conventions in play is potentially more dangerous that having one that is technically incorrect.

However more often than not there are multiple conventions in play in which case I use the whatever is in use in that part of the installation.

I don't tend to do many new installs, mostly additions and alterations.

 

[Toneyz]

I don’t know?
When I worked at Tate and Lyle, we used to use the phase colours for all circuits.
I dread to think what the trunking will look like now Black is a phase colour.

I suppose using L1, L2, L3 there would be no confusion.

 

[Lucien Nunes]

I'm puzzled why it should be absolutely prohibited though: brn, blk, and gry are clearly legit phase colours, so as long as the remaining two are clearly sleeved blu & grn/yel at both ends, where's the danger?

There is a problem now that two colour systems exist, which is that a single-phase distribution circuit on the black phase (harmonised colours) would have a black line and a blue neutral, while one on the blue phase (old colours) would have a blue line and a black neutral. This is the only situation with completely ambiguous polarity, as in any 3-phase circuit the colours of the other phases imply the functions of blue and black. Requiring the line to be brown on a single-phase distribution circuit prevents possible confusion.

Historically, I did prefer phase identification colours and wired many distribution circuits that way. I would tag the line on a 2-core MI submain with the phase colour too.

 

[Toneyz]

Of course on commercial jobs, we now identify using Brother printed labels, engraved labels etc. Which helps.

 

[Bobster]

I don’t know?
When I worked at Tate and Lyle, we used to use the phase colours for all circuits.
I dread to think what the trunking will look like now Black is a phase colour.

From what I remember the panels I designed for Tate and Lyle all phase colours were black, but every wire was numbered. It was also a control suit so not exactly the same as distribution.