Which of the following types of insulation is affected by the temperature rating?

The type of insulation that is affected by the temperature rating is crucial for ensuring the safety and efficiency of electrical systems. THW (Thermoplastic Heat and Water-resistant) and THHW (Thermoplastic Heat, Water, and Oil-resistant) insulation types are specifically designed to withstand certain temperature ranges and environmental conditions.

These ratings indicate the specific temperatures the insulation can handle without degrading or losing performance. For example, THW insulation typically has a lower temperature rating compared to THHW, which is designed for more demanding conditions. Thus, selecting the proper insulation based on its temperature rating is essential in applications where heat resistance and moisture control are considerations.

In contrast, metallic insulation relates more to other conductivity properties rather than temperature rating. Mineral insulation generally refers to materials like mineral wool which are typically used for thermal insulation, but not necessarily affected by electrical temperature ratings. Cross-linked polyethylene insulation is designed to provide certain thermal and electrical properties, but it does not have the same explicit temperature rating implications as THW and THHW.

Therefore, the focus on THW and THHW demonstrates an understanding of how electrical insulation is graded and selected based on its thermal and environmental resistance, making these two types the correct answer concerning temperature ratings.