Wiring means transmission of electricity through insulated conductors and that is how power is supplied in buildings and other areas. There are various wiring codes that one has to adhere to before manufacturing of wires so as to ensure protection from electric shocks and so there are various color codes also that give even a layman idea about wires. The wiring depends on many factors like the power consumption by the intended user, environment in which wiring needs to be done, national and local regulations, etc. even wires and cables undergo rating wires and cables are rated on various factors like the circuit voltage, temperature rating, and environment in which they can be used apart from these wire or cable has a voltage rating, and a maximum conductor surface temperature rating. CRT technology is highly used these days and special CRT wires are required for the same.