What type of rope is considered an insulator when clean and dry?

Polypropylene is considered an insulator when clean and dry due to its chemical structure and low moisture absorption properties. As a synthetic material, polypropylene does not conduct electricity, making it an effective choice for situations where insulation is needed. Its lightweight nature and resistance to rot and mildew also contribute to its suitability as an insulator in various conditions.

Other ropes, such as nylon and polyester, while strong and durable, can absorb moisture which may reduce their insulating properties. Manila rope, derived from natural fibers, can conduct electricity when wet and is not ideally suited as an insulator. Thus, polypropylene stands out as the most appropriate answer in terms of insulation characteristics when kept clean and dry.