Final answer:
In a PSC multi-speed indoor blower, the wire always connected to power regardless of speed is the common wire. It serves as the return path for current and completes the circuit for all motor speeds.
Step-by-step explanation:
In PSC (Permanent Split Capacitor) multi-speed indoor blowers, the wire that is wired to power regardless of speed is known as the common wire. This wire, typically color-coded white or blue depending on regional standards, is the return path for the current to complete the circuit. It is connected to the earth at the power source and at the user location, providing safety and allowing it to carry current back without leading to a potential difference with respect to the ground. Understanding the wiring of such systems is crucial for proper installation and maintenance, ensuring safety against electrical shock and appliance malfunction.
The neutral wire, often confused with the common wire, is also connected to the earth, which forces it to be at zero volts relative to the earth, making it safe to touch under most circumstances. However, in a PSC motor, the common wire is the one that completes the circuit for all motor speeds. Therefore, the common wire is connected to the power supply regardless of the blower speed and is essential for the blower's operation.