Heat is the number one killer of electrical components. Inside a control cabinet, every device from circuit breakers to contactors to drives generates heat during normal operation. If that heat cannot escape, component temperatures rise. For every 10°C above rated operating temperature, the lifespan of electrical components can be cut in half.
Most overheating problems come down to three common mistakes.
The first mistake is insufficient enclosure sizing. Manufacturers provide heat dissipation data for their components. Add up the total heat load in watts. Then compare that to your enclosure's natural convection cooling capacity. A packed cabinet with no breathing room will overheat regardless of the ambient temperature.
The second mistake is poor component layout. Placing heat-generating devices like variable frequency drives near sensitive control components forces hot air directly over parts that need cool operation. The fix is simple: group heat-producing components together near the top or side of the cabinet and position sensitive components lower where cooler air settles.
The third mistake is ignoring filters and fans. Forced ventilation works when designed correctly. But filters clog over time. A clogged filter blocks airflow just as effectively as a closed door. Inspection every three months is reasonable for clean environments. For dusty locations like cement plants or wood shops, monthly filter checks are necessary.
What about sealed cabinets? For outdoor or wash-down environments where fans cannot be used, air conditioners or vortex coolers are required. These cost more upfront but prevent premature component failure in harsh conditions.
We have built control cabinets for steel mills, automotive plants, and cement factories. In every case, thermal management was discussed before the first drawing was made. If you are specifying a control cabinet, ask your supplier about heat load calculations. A supplier who cannot answer that question is not the right partner for your project.