Conductor Colour Codes
Conductor Colour Codes
(OP)
I am designing a control system for an international (IEC standard) customer and would like to verify the colour coding for the conductors:
3 Phase
Phase A - Black
Phase B - Red
Phase C - White
Neutral - Light Blue
Single Phase
AC Power - Black
AC Control - Red
AC Neutral - Light Blue
DC Control - Blue
Interconnect Control (externally powered) - Orange
Ground - Green/Yellow
I have seen some places that single phase colour coding is:
AC line - Brown
AC neutral - Light Blue
DC control - ????
I am a little confused in this matter - any insight would be helpful and references to specific standards are appreciated.
3 Phase
Phase A - Black
Phase B - Red
Phase C - White
Neutral - Light Blue
Single Phase
AC Power - Black
AC Control - Red
AC Neutral - Light Blue
DC Control - Blue
Interconnect Control (externally powered) - Orange
Ground - Green/Yellow
I have seen some places that single phase colour coding is:
AC line - Brown
AC neutral - Light Blue
DC control - ????
I am a little confused in this matter - any insight would be helpful and references to specific standards are appreciated.





RE: Conductor Colour Codes
Good Luck
Christopher Caserta
ccaserta@us.tuv.com
Ph:904-225-0360
RE: Conductor Colour Codes
Below the colour codes we use in Europe...
3PHASE:
Phase L1 Brown
Phase L2 Black 1
Phase L3 Black 2
Neutral Blue
Safety- ground, instrument-ground Green Yellow
1PHASE:
AC Power main current - Brown
AC Control - Switched main current,
230VAC controlling current Black
Neutral Blue
Safety- ground, instrument-ground Green Yellow
Other AC Voltage:
From save altered Current (24VAC, 42VAC ……) Red
Common from save altered current White
Safety- ground, instrument-ground Green Yellow
DC Voltage:
Phase from save direct current (plc inputs etc) Orange
Common from save direct current Green
Measurement signals Yellow
Voltage initiated in relay assembly Purple
Hazards direct current Grey
Safety- ground, instrument-ground Green Yellow