NEC Commercial Electrical Practice Test

In Class I, Division 2 locations using motors, what is the purpose of employing space heaters during shutdown periods?

1. To provide heat

2. To prevent condensation

3. To enhance efficiency

4. To reduce noise

The correct answer is: To prevent condensation

In Class I, Division 2 locations, which are designated for hazardous locations where flammable gases or vapors may be present under abnormal conditions, the use of space heaters during shutdown periods serves a critical function in preventing condensation. When temperatures fluctuate, moisture can condense on cold surfaces, potentially leading to the accumulation of water in electrical enclosures or on critical components. This condensation can create a hazardous environment, increasing the risk of corrosion or short circuits, and may also allow for the formation of explosive atmospheres if flammable materials are present. By using space heaters, the internal temperatures of these enclosures can be maintained above the dew point, effectively reducing or eliminating the possibility of moisture accumulation. In contrast, while providing heat might be a general function of space heaters, the primary safety concern in these hazardous areas is the prevention of condensation and its associated risks. Other choices, such as enhancing efficiency or reducing noise, are not relevant to the specific context of using space heaters in hazardous locations.