The r.m.s. potential difference between the red live wire and black neutral wire in Indian domestic electric supply is

In the Indian domestic electric supply system, the potential difference between the live wire (typically color-coded red) and the neutral wire (typically color-coded black) is maintained at a root mean square (r.m.s.) value of 220 V [1]. While the nominal standard for single-phase supply in India is often cited as 230 V in modern technical standards, educational textbooks and standard domestic circuit descriptions consistently specify 220 V as the standard potential difference for household appliances [2]. The live wire carries a high alternating potential, whereas the neutral wire is maintained at a potential close to that of the earth (0 V). This 220 V r.m.s. value represents the effective voltage delivered to single-phase residential connections, operating at a frequency of 50 Hz.

Sources

1. [1] Science , class X (NCERT 2025 ed.) > Chapter 11: Electricity > EXERCISES > p. 194
2. [2] Science , class X (NCERT 2025 ed.) > Chapter 11: Electricity > Example 11.10 > p. 189