3 Phase Wire Colours on L1 L2 L3 Single Phases

[Chris_1969]

Hi all,

I am looking at a system that is supplied with a 3 phase supply and into a cabinet. Then external to the cabinet L1 and Neutral feed unit one, L2 and Neutral feed unit two, L3 and Neutral feed unit three.

Units one, two and three are at a distance of 50 meters from the cabinet.

What colour must be used between the cabinet and each of the units? What reg covers this?

Many thanks,
Chris.

 

[uksrevivor]

Hi Chris welcome to the forum.
Im not sure what you mean by units? unit 1 2 and 3 have been fed via each of the 3 phases to provide single phase power (230V)
If I am correct the cable supplying each unit will be of the new colours and that will come under the harmonization of cable colours regulation March 2004. Amendment No 2, 2004 of BS 7671:2001, This will all depend on when it has been installed as the old 3 phase colours were phased out by 2006. A bit more information would be helpful like what is a unit/cabinet and what cable is being used between the cabinet and units. With more information im sure a more experienced member will be able to help you.

 

[Steveyboy10]

The 3 phases l1 l2 and l3 would be coloured brown black and grey. Neutral would be blue.
The phases coming out sound as you have described as though they are going to 3 separate distribution boards which are single phase. Therefore they would be all brown with a blue neutral.

 

[Chris_1969]

Hi all,

Many thanks for the welcome and responses.

The 'units' are pieces of equipment that are identical (production line testers) and are both powered and controlled by the single cabinet (that is fed by a 3 phase supply). There are actually 12 units and phase 1 from the cabinet is powering units 1,4,7,10. Phase 2 is powering units 2,5,8,11 and phase 3 the other units. This is new equipment just waiting to be installed.

A 17th edition guy has specified that we can use the 3 phase colours to wire the units. So before we do I would like to check and have something I can evidence.

Many thanks,
Chris.

 

[Richard Burns]

See table 51 of BS7671, for a single phase circuit the line conductor should be brown. It is possible to identify cables at their terminations with "L" or colour sleeving, but the preference is to identify the cable at all points.

 

[westward10]

What is a 17th Edition Guy?

 

[Flanders]

As others as said if you are runnig singles phase circuits regardless of comming from a 3 phase board or a singles phase board the line conducters should be brown and the neutrals blue , i think it was back in the 15th addition that you could use the red yellow and blue phase colours for single phase circuits.

 

[telectrix]

What is a 17th Edition Guy?

someone who reads the regs book instead of using it to support a broke chair leg.

 

[7029 dave]

I like red yellow blue, and red and black, proper colours.

 

[Toneyz]

who were we harmonizing with

 

[Risteard]

As others as said if you are runnig singles phase circuits regardless of comming from a 3 phase board or a singles phase board the line conducters should be brown and the neutrals blue , i think it was back in the 15th addition that you could use the red yellow and blue phase colours for single phase circuits.

It was never allowed for final circuits - only distribution circuits (or submains as they were then known).

 

[Flanders]

It was never allowed for final circuits - only distribution circuits (or submains as they were then known).

Thanks, I have come across old sites with single phase final circuits wired in the relevant phase colours that why I thought is was a 15th addition Reg.

 

[Risteard]

Thanks, I have come across old sites with single phase final circuits wired in the relevant phase colours that why I thought is was a 15th addition Reg.

No. It was certainly done by some but it was never permitted by the IEE Wiring Regulations.

 

[Besoeker]

who were we harmonizing with

Good question.
I came across a British guy who was building a new house in France. A quite large new house with a three phase supply. It was after the new harmonised colours became mandatory for new installations. He was using red, yellow, blue, and black.

If were cynical I'd say he was using UK cables that had to be disposed of because of the new regs.