Where to measure temperature in the distribution box

Temperature in a distribution box should be measured at key points such as busbars, circuit breaker connections, and other high-current contact points, using either multi-point sensors or infrared thermography.

Key Measurement Points

1. Busbars and Main Connections: These are primary heat-generating components due to high current flow. Measuring temperature here helps detect excessive resistance or loose connections that could lead to overheating .
2. Circuit Breaker Terminals and Lugs: Connection points often show slightly higher temperatures than surrounding areas. Hotspots here may indicate oxidation, loose screws, or aging components .
3. Outgoing Feeder Connections: Monitoring these ensures that secondary circuits are not overloaded and helps identify localized heating issues .
4. Internal Air Temperature: Installing sensors inside the cabinet can provide an overall view of the thermal environment, which is useful for controlling cooling systems like fans .

Measurement Methods

• NTC or PT100/1000 Sensors: Multi-point temperature sensors can be installed at critical locations inside the cabinet. These sensors provide continuous monitoring and can trigger cooling mechanisms if temperatures exceed safe limits .
• Infrared Thermography: Periodic thermal inspections using an IR camera allow detection of hotspots without direct contact. For accurate readings, IR-transparent windows or IR inspection ports may be used to maintain safety and enclosure integrity .
• Continuous Monitoring Systems: Advanced setups use multiple sensors combined with software to create a 3D thermal map of the distribution box, identifying both localized and overall temperature trends .

Practical Tips

• Measure while the equipment is energized to capture real operating conditions .
• Ensure sensors are placed near high-current components and points prone to resistance.
• Combine sensor data with visual inspections to detect early signs of component aging or connection issues .
• Maintain periodic calibration of sensors and IR equipment for accurate readings. By strategically placing temperature sensors and using thermal imaging, you can effectively monitor the distribution box, prevent overheating, and extend the lifespan of electrical components.