28 June 2021
The voltage tolerance level for the electrical auxiliaries (example: undervoltage release(Mn), shunt coil(Mx)) used in Low Voltage Circuit Breakers is defined as per the IEC 60947-2 standard.
The tolerance level defined by IEC60947-2 is 0.85% for minimum nominal voltage (Un) and 1.1% for maximum nominal voltage (Un).
For Un = 230/240V, Minimum tolerance Level is (0.85% of 230V AC) = 195.5V, Maximum tolerance Level is (1.1% of 240V AC) = 264 VAC. This means voltage range : 195.5 VAC - 264 VAC.