Which of the following statements is true regarding raceways and moisture control?

The statement about raceways needing to be filled with approved materials to prevent condensation is accurate. In environments where moisture is a concern, using appropriate filler materials within raceways can help mitigate issues related to condensation. Condensation can lead to water accumulation, which poses risks such as corrosion of electrical wires, short circuits, and overall degradation of electrical integrity.

By employing approved materials that can absorb excess moisture or prevent water ingress, raceways contribute to a safer and more reliable electrical installation. This practice not only promotes the longevity of the wiring but also enhances safety by minimizing the potential for electrical faults that could arise from moisture exposure.

In contrast, raceways cannot be arbitrarily installed in all environments, particularly visibly wet areas without proper waterproofing considerations, which is highlighted in other options. While air circulation and heat insulation can also play roles in moisture control, they do not address the specific requirement of using materials that actively prevent condensation, which is a critical factor in maintaining electrical system integrity.