Industrial colour coding is a standardization method employed to improve industrial safety and efficiency. They are internationally recognized color codes that facilitate recognition of different conduits and electrical wires.
The essence of colour coding is to facilitate convenience, promote safety, and make the facility/equipment easy to maintain.
Colour coding for electrical installations
From the grid, the transformers step down the power to a voltage level that the final consumer can use safely. Consequently, a typical three-phase connection has R (red), Y (yellow), B (blue) and black (neutral) cables. However, the R, Y, and B cables are live.
The potential difference between any two of the R, Y, and B is 440 volts while the potential difference between the neutral (black) cable and any of the three ranges between 220 – 240 volts. Usually, the earth wire is green with/without a yellow stripe.
Colour coding for utility installations
Piped water: – sky blue color
Chilled water: – usually insulated and normally has a green arrow on the insulating material showing the direction of flow.
Hot water pipes: – also insulated and has a red arrow on the insulating material showing the direction of flow
Steam: – uses the ame colour coding as hot water (red arrow). The word steam is optional
Condensate/used steam: – black color
Compressed air: – light green color
Vacuum: – yellow color
Ammonia refrigerant lines: – dark red (maroon)
Other refrigerants (Freon/CFCs): – bare copper tubes