Electrical Wiring Color Codes

A field reference for electricians, apprentices and anyone who needs to get the colours right. No signal required.

COLOUR CODES BY REGION
• UK & EU — current harmonised colours and pre-2004 legacy colours
• US & Canada — NEC branch circuit and 277/480V conventions
• Australia & New Zealand, India & South Asia
• The orange high leg, and why it destroys 120V equipment
• DC, solar and flexible cord conventions

CABLE SIZING
• AWG and metric sizes with typical ampacity
• Derating for grouping, ambient temperature and insulation
• Voltage drop on long runs
• Copper versus aluminium

PROTECTION & SYSTEMS
• RCD and GFCI types
• MCB trip curves B, C and D
• Three phase, star and delta
• TN-S, TN-C-S and TT earthing arrangements

PRACTICAL
• Two-way and intermediate switching
• Safe cable zones in walls
• Ring final circuits
• RJ45 pinouts, PoE classes, thermostat wire conventions
• Order of initial verification tests

• Completely offline
• Fast search across every card
• Save the references you use most

IMPORTANT
This is a reference, not a qualification. Electrical work is regulated in most countries. Always isolate, lock off and prove dead before working. Colour conventions have changed over the decades — never assume a conductor's function from its colour. Test every time.

Free, with ads.