What is the status of the blue wire in a plug?

The blue wire in a plug is designated as the neutral wire. In electrical systems, the neutral wire serves an essential role by providing a return path for the current to complete the circuit safely. It carries the current back to the power source and is typically at or near ground potential, meaning it does not carry a high voltage relative to the earth.

Understanding the function of the neutral wire is crucial for safety and proper electrical wiring. The neutral wire is generally insulated and colored blue in many regions, following standardized wiring color codes to help electricians and technicians easily identify each wire's purpose.

In contrast, the live wire, commonly colored brown, carries the current from the power source to the appliance, while the earth or ground wire, often colored green/yellow, provides a safety path for excess electrical current in case of a fault. Proper identification and understanding of these wires are vital for both operating and troubleshooting electrical devices.