The link in the neutral and the fuse in the phase of an AC circuit are provided for safety and functional reasons. Here's why:
1. Link in the Neutral:
- The
neutral line is intended to carry the return current from the load back to the source. It's at or near ground potential (zero volts) for safety.
- A
link (or switch) in the neutral is sometimes provided to isolate the entire load from the supply when needed. In some situations, this link can be used to disconnect the neutral side for maintenance or safety reasons.
- The main reason for placing a link in the neutral is to
ensure that both the phase and neutral conductors can be safely isolated during maintenance or fault conditions. If you only disconnect the phase, the neutral could still be live, creating a shock hazard.
So, the link in the neutral allows you to disconnect the return path from the load safely, ensuring no current flows through the system during maintenance.
2. Fuse in the Phase:
- The
fuse is a protective device that blows (or disconnects the circuit) when excessive current flows through the circuit, protecting the system from damage.
- The fuse is placed in the
phase (live) line because the phase is the
"active" conductor that supplies current to the load.
- If the fuse were placed in the neutral line instead of the phase, the load could still have power even if the neutral is disconnected. This would lead to dangerous situations, as part of the circuit could still be "live" even though the fuse has blown.
- By placing the fuse in the
phase line, when the fuse blows, it completely disconnects the load from the power supply, ensuring the circuit is safely isolated from any electrical supply.
In summary:
- Link in the neutral is for safe isolation of the load's return path.
- Fuse in the phase ensures protection by completely disconnecting the load in case of a fault.
This setup helps prevent electric shocks and equipment damage while maintaining safety and reliability in the circuit.