In the United Kingdom the British Standard BS-AU7 determines color coding of automobile wiring. Lucas use a 7 color set in which plain colors - purple, green, blue, red, white, brown and green are supplemented by a further group using a base color with a thin line trace of a different color, thus:
 
Black earth (ground) connections
Green feeds to auxiliary devices controlled by the ignition switch, eg wipers, flashers, etc
White base color for ignition circuits
Red sidelights (parking lights) and rear lights
Blue with white trace main beam headlamp with red trace - dip (meeting) beam headlamp
Purple auxiliary devices not fed via the ignitior switch, eg horn, interior light
Brown main battery feed

Other colors are used, according to equipment specifications, eg light green, pink, slate. Handbooks are usually printed in black and white only, so the cable colors are identified by a lettering code, such as:
 
 

B Black P Purple
U Blue G Green
N Brown S Slate
R Red  W White

When a cable has a base color and a second color spiral trace the code is two letters, for example: WG = White with green trace
 
 

Main
Tracer
Destination
Black
  All earth connections
Black
Blue
Tachometer generator to tachometer
Black
Brown
Tachometer generator to tachometer
Black
Green
Screenwiper switch to screenwiper (single speed) relay to radiator fan motor
Black
L. Green
Vacuum brake switch to warning light and/or buzzer
Black
Orange
Radiator fan motor to thermal switch
Black
Pink
 
Black
Purple
 
Black
Red
Electric speedometer
Black
Slate
 
Black
White
Brake fluid level warning light to switch and handbrake switch
Black
Yellow
Electric speedometer
Blue
  Lighting switch (head) to dipper switch
Blue
Black
 
Blue
Brown
 
Blue
Green
 
Blue
L. Green
Screenwiper motor to switch
Blue
Orange
 
Blue
Pink
Headlamp dip beam fuse to left hand headlamp (when independently fused)
Blue
Purple
 
Blue
Red
Dipper switch to headlamp dip beam. Headlamp dip beam fuse to right-hand headlamp (when independently fused)
Blue
Slate
Headlamp main beam fuse to left hand headlamp or inboard headlamps (when independently fused)
Blue
White
Dipper switch to main beam (subsidiary circuit headlamp flasher relay to headlamp). Headlamp main beam fuse to right-hand headlamp (when independently fused). Headlamp main beam fuse to outboard headlamps (when outboard headlamps independently fused). Dipper switch to main beam warning light
Blue
Yellow
Long range driving switch to lamp.
Brown
  Main battery feed
Brown
Black
Alternator warning light, negative side
Brown
Blue
Control box (compensated voltage control only) to ignition and ignition switch, eg wipers, flashers, etc lighting switch (feed)
Brown
Green
Dynamo F to control box F Alternator field F to control box F
Brown
L. Green
Screenwiper motor to switch
Brown
Orange
 
Brown
Pink
 
Brown
Purple
Alternator regulator feed
Brown
Red
Compression ignition starting aid to switch. Main battery feed to double pole ignition switch (a.c. alt. system)
Brown
Slate
 
Brown
White
Ammeter to control box. Ammeter to main alternator terminal
Brown
Yellow
Dynamo D to control box Dand ignition warning light. Alternator neutral point
Green
  Accessories fused via ignition switch (subsidiary circuit fuse A4 to hazard switch (terminal 6)) 
Green
Black
Fuel gauge to fuel tank unit or changeover switch
Green
Blue
Water temperature gauge to temperature unit
Green
Brown
Reverse lamp to switch
Green
L. Green
Hazard flasher unit to hazard pilot lamp
Green
Orange
Low fuel level warning light
Green
Pink
Choke solenoid to choke switch (when fused)
Green
Purple
Stop lamps to stop lamp switch
Green
Red
Left-hand flasher lamps
Green
Slate
Heater motor to switch (or to fast)(on 2-speed motor)
Green
White
Right-hand flasher lamps
Green
Yellow
Heater motor to switch, single speed (or to slow on two-speed motor)
L. Green
  Instrument voltage stabilizer to instruments
L. Green
Black
Screen jet switch to screen jet motor
L. Green
Blue
Flasher switch to left-hand flasher warning light
L. Green
Brown
Flasher switch to flasher unit L
L. Green
Green
 
L. Green
Orange
 
L. Green
Pink
Flasher unit L to emergency switch (simultaneous flashing)
L. Green
Purple
Flasher unit F to flasher warning light
L. Green
Red
Fuel tank changeover switch to right-hand tank unit
L. Green
Slate
Fuel tank changeover switch to left-hand tank unit
L. Green
White
 
L. Green
Yellow
Flasher switch to right-hand flasher warning light
Purple
  Accessories fused direct from battery
Purple
Black
Horn or horn relay to horn push
Purple
Blue
 
Purple
Brown
Horn fuse to horn relay (when horn is fused separately)
Purple
Green
 
Purple
L. Green
 
Purple
Orange
Aerial lift motor switch DOWN
Purple
Pink
 
Purple
Red
Boot light switch to boot light
Purple
Slate
Aerial lift motor to switch UP
Purple
White
Interior light to switch (subsidiary circuitdoor safety lights to switch )
Purple
Yellow
Horn to horn relay
Red
  Side and tail lamp feed
Red
Black
Parking switch to left-hand side lamp
Red
Blue
 
Red
Brown
Variable intensity panel lights (when used in addition to normal panel lights)
Red
Green
Lighting switch to side and tail lamp fuse (when fused)
Red
L. Green
Screenwiper motor to switch
Red
Orange
Parking light switch to right-hand sidelamp
Red
Pink
 
Red
Purple
Map light switch to map light
Red
Slate
 
Red
White
Panel light switch to panel lights
Red
Yellow
Fog lamp switch to fog lamp
Slate
  Window lift
Slate
Black
Window lift
Slate
Blue
Window lift
Slate
Brown
Window lift
Slate
Green
Window lift
Slate
L. Green
Window lift
Slate
Orange
Window lift
Slate
Pink
Window lift
Slate
Purple
Window lift
Slate
Red
Window lift
Slate
White
Window lift
Slate
Yellow
Window lift
White
  Ignition control circuit (unfused) (ignition switch to ballast resistor)
White
Black
Ignition coil CB to distributor contact breaker. Rear heated window to switch or fuse TAC ignition
White
Blue
Choke switch to choke solenoid (unfused). Rear heater fuse unit to switch. Electronic ignition TAC ignition unit to resistance.
White
Brown
Oil pressure switch to warning light or gauge
White
Green
Fuel pump No. 2 or left-hand to change-over switch
White
L. Green
Screenwiper motor to switch
White
Orange
Hazard warning feed (to switch)
White
Pink
Radio from ignition switch
White
Purple
Fuel pump No. 1 or right-hand to change-over switch
White
Red
Solenoid starter switch to starter push or inhibitor switch
White
Slate
Tachometer to ignition coil
White
Yellow
Starter inhibitor switch to starter push. Ballast resislor to coil. Starter solenoid to coil
Yellow
  Overdrive
Yellow
Black
 
Yellow
Blue
Overdrive
Yellow
Brown
Overdrive
Yellow
Green
Overdrive
Yellow
L. Green
Screenwiper motor to switch
Yellow
Orange
 
Yellow
Pink
 
Yellow
Purple
Overdrive
Yellow
Red
Overdrive
Yellow
Slate
 
Yellow
White