Question

A portion of electric circuit diagram of a household wiring is given.

• [(a)] What does the part marked as “X” represent in the circuit?
• [(b)] Draw a circuit diagram of a branch circuit which includes one three pin socket with switch.

Hint:

Switch must always be in live wire for safety in household wiring.

Answer 1

(a) Identification of part “X”
Concept: Household wiring components
In a typical household circuit, the sequence includes: \[ \text{Main supply} \rightarrow \text{Main fuse} \rightarrow \text{Energy meter} \rightarrow \text{ELCB} \rightarrow \text{Distribution board} \] Step 1: Position of X}
The part “X” is placed after the main fuse and before ELCB. Step 2: Identify the component}
This component measures electrical energy consumed. Conclusion (a): \[ X = \text{Energy meter (Electric meter)} \] (b) Circuit diagram of a branch circuit with three-pin socket and switch
Concept: Three-pin socket connection
A three-pin socket has:

• Live (L)
• Neutral (N)
• Earth (E)

Step 1: Connections}

• Live wire passes through a switch to the socket.
• Neutral wire directly connects to the socket.
• Earth wire connects to the earth pin.

Step 2: Diagram}
\[ \begin{array}{c} \text{Live (L)} \;\; \longrightarrow \;\; \boxed{\text{Switch}} \;\; \longrightarrow \;\; \boxed{\text{Socket (L)}

\text{Neutral (N)} \;\; \longrightarrow \;\; \boxed{\text{Socket (N)}

\text{Earth (E)} \;\; \longrightarrow \;\; \boxed{\text{Socket (E)}} \end{array} \] Step 3: Explanation}

• Switch is always connected in live wire for safety.
• Earth wire prevents electric shock.

Conclusion (b): \[ \text{Branch circuit includes live with switch, neutral direct, and earth connection.} \]