A cable's voltage grade is the maximum working voltage its insulation is designed and tested to withstand safely. It is sometimes written as Uo/U (the voltage to earth and the voltage between conductors), and it describes the insulation's capability — not the supply you are obliged to connect.
For general low-voltage wiring the common grade is 1100 V, which comfortably covers India's 230 V single-phase and 415 V three-phase supplies — see the practical explanation under what the 1100V grade means. Distribution at higher voltages uses cables specifically rated as medium voltage (MV) or high voltage (HV).
The essential rule is that the circuit voltage must never exceed the cable's grade. Voltage grade is one of several selection parameters alongside current-carrying capacity and conductor size.
APAR's 1100 V-grade house wires and cables are available in PVC and low-smoke HR-FR-LSH grades for homes and commercial buildings.