How is a polarity test performed on a socket outlet and what indicates correct wiring?

• A. Using a tester to ensure live is on the correct terminal, neutral on neutral, and earth on earth
• B. Visually inspecting the socket
• C. Measuring insulation between live and earth
• D. Checking earth continuity between earth and metalwork

Answer: (A)

Polarity testing checks that the live, neutral, and earth conductors are connected to the correct terminals in a socket outlet. Using a tester designed for this purpose, the outlet is plugged in and the readout or pattern of lights confirms that live is on the live terminal, neutral on the neutral terminal, and earth on the earth terminal. This direct verification ensures the outlet will energize and protect correctly, and that appliances connected to it won’t be exposed to reversed wiring.

Visual inspection alone can miss hidden wiring faults. Measuring insulation between live and earth checks insulation resistance, not whether the live and neutral are correctly located. Checking earth continuity to metalwork confirms an earth path exists, but doesn’t verify that the live and neutral are connected to the correct terminals.