Question 10 QMED02 - Electrician-Refrigerating Engineer

The Correct Answer is D **Explanation for Option D (Correct Answer):** Option D, **using strip heaters inside the switch box**, is the correct solution. Condensation occurs when the temperature of the air inside the enclosure drops below the dew point, causing water vapor to change into liquid water on the cooler surfaces (like the internal components of the master switches). Strip heaters, or anti-condensation heaters, are designed to maintain the internal temperature of the enclosure slightly above the ambient temperature. This controlled elevation in temperature keeps the relative humidity inside the box low, preventing moisture from condensing on the electrical components, thereby effectively reducing moisture damage. **Explanation of Incorrect Options:** * **A) venting the switch box regularly:** While ventilation can equalize pressure and reduce stagnant moist air, simply 'venting regularly' is not a dedicated, automated preventative measure against condensation, especially in humid or rapidly cooling environments (like those encountered at sea). In certain conditions, opening the box for venting might actually introduce more moist air. * **B) coating the switch box internals with epoxy sealer:** Epoxy sealing is typically used for environmental protection (like dust or minor splashing) or to secure components, but it does not address the fundamental thermodynamic problem of condensation forming inside the enclosure on the electrical contacts and terminals. If water condenses, it will still sit on the sealed surfaces or find unsealed contact points. * **C) installing a light bulb in the pedestal stand:** While a standard incandescent light bulb does generate heat, this method is an inefficient and often unreliable way to provide precise, regulated heating for condensation control within a specialized electrical enclosure like a master switch box. Dedicated strip heaters are engineered for uniform, controlled temperature maintenance necessary for industrial applications.