In domestic wiring, the fuse or switch is always inserted in:

Explanation:

Domestic Wiring and the Role of Fuses/Switches

Introduction: In domestic electrical wiring, the safety and functionality of the system are paramount. One crucial aspect of ensuring safety is the proper placement of fuses and switches. Fuses and switches play an essential role in protecting electrical circuits and preventing potential hazards such as electrical fires and shocks.

Correct Option Analysis:

The correct option is:

Option 1: Series with the phase of supply

This option correctly describes the standard practice in domestic wiring. The fuse or switch is always inserted in series with the phase (live) wire of the supply. This ensures that when the switch is turned off or the fuse blows, the circuit is completely disconnected from the live supply, thus preventing any flow of current and ensuring safety.

Additional Information

To further understand the analysis, let’s evaluate the other options:

Option 2: Series with the neutral of supply

This option is incorrect. Placing the fuse or switch in series with the neutral wire does not provide the same level of safety. If the fuse blows or the switch is turned off, the circuit might still have live voltage present, which can pose a significant risk of electric shock or fire. The primary purpose of a fuse or switch is to ensure that when it operates, it completely disconnects the circuit from the live supply, which can only be achieved by placing it in series with the phase wire.

Option 3: Parallel with the phase of supply

This option is also incorrect. A fuse or switch cannot be placed in parallel with the phase wire as it would not interrupt the flow of current in the event of a fault. Instead, it would create an alternate path for the current, which defeats the purpose of having a protective device. Fuses and switches must be placed in series to effectively control and protect the circuit.

Option 4: Series with the earthing of supply

This option is incorrect as well. The earthing system is designed to provide a path for fault currents to safely dissipate into the ground, protecting both people and equipment. Placing a fuse or switch in series with the earthing system would compromise its effectiveness and could lead to dangerous situations. The fuse or switch must be placed in series with the phase wire to ensure proper circuit protection.

Conclusion:

In domestic wiring, the correct placement of fuses and switches is crucial for ensuring the safety and functionality of the electrical system. The fuse or switch must be inserted in series with the phase (live) wire of the supply to effectively disconnect the circuit from the live voltage when necessary. This practice helps prevent electrical hazards such as shocks and fires, ensuring a safe living environment. Understanding the importance of proper fuse and switch placement is essential for anyone involved in electrical installation and maintenance.