The recommended relative humidity for a distribution box is generally between 45% and 75% to prevent condensation, corrosion, and static discharge.

Recommended Humidity Range

For electrical distribution rooms and enclosures, the relative humidity should be maintained between 45% and 75%. Humidity levels below 45% can increase the risk of static electricity, which may damage sensitive electronic components, while levels above 75% can lead to condensation, corrosion, and insulation breakdown in electrical equipment . Sudden changes in humidity should also be avoided, with variations ideally not exceeding 6% per hour to protect both equipment and personnel comfort .

Temperature Considerations

Distribution boxes should also be kept within a safe temperature range, typically 5°C to 40°C, depending on the specific equipment specifications. Maintaining even temperature distribution helps prevent localized overheating and reduces the risk of condensation forming inside the enclosure .

Condensation Prevention

Condensation occurs when warm, humid air contacts cooler surfaces inside the enclosure, reaching the dew point and forming water droplets. To prevent this, distribution boxes should be well-sealed, thermally insulated, and equipped with airflow or ventilation systems. Additional measures include using heaters controlled by hygrostats or hygrotherms, which activate when humidity rises above a set threshold or when temperatures drop too low .

Monitoring and Control

To ensure optimal conditions, it is recommended to install environmental monitoring systems that track temperature and humidity in real time. Automated alarms and responses can help maintain the humidity within the safe range, protecting the equipment from moisture-related damage and ensuring long-term reliability . By maintaining 45%–75% relative humidity, controlling temperature, and monitoring environmental conditions, distribution boxes can operate safely and efficiently while minimizing the risk of equipment failure due to moisture or static electricity.