The range of ambient temperature is from -10 to 40 degree Celsius for not only MCCB but also including Earth Leakage Circuit breaker, Earth Leakage Relay and Circuit protector. Therefore, please use circuit breakers with the temperature. (However, the average of temperature should not exceed rather than 35 degree Celsius within 24 hours.) Moreover, the rated ambient temperature of overcurrent trip characteristics is adjusted to 40 degree Celsius. (The rated ambient temperature for circuit protector is 25 degree Celsius.)