# Environmental Conditions

This standard applies to equipment designed to be safe under the following conditions:

- Indoor use.

- Altitude up to 2 000 m.

- Maximum relative humidity 80% for temperatures up to 31 °C decreasing linearly to 50% relative humidity at 40 °C.

- Transient overvoltage up to the levels of overvoltage category II NOTE: These levels of transient overvoltage are typical for equipment supplied from the building wiring.

- Temporary overvoltage occurring on the mains supply.

- Applicable pollution degree of the intended environment.(degree 2 in most cases).

- Mains supply voltage fluctuations up to ±10 % of the nominal voltage.

- Transient over voltages typically present on the mains supply

- Transient overvoltage up to the levels of overvoltage category II

- Pollution degree 2