Wire Color Code is a great app for electricians in the United States. Its a an electrical wiring color cheat sheet in your pocket. It allows you to know which color wire to pull for each circuit.
The app comes with 3 power systems and 1,000 circuits each:
• 1 phase 120V / 240V (black, red)
• 3 Phase 120V / 208V (black, red, blue)
• 3 Phase 277V / 480V (brown, orange, yellow)
The app also lets you search by circuit number. You enter the number and the app shows you the corresponding color. Its easy!