There are many wire insulator materials available. Shown here are some of the most popular ones and their advantages and disadvantages. There is a large variety of formulations available, which allows many of these materials to be formulated to meet specific requirements. PVC is the most common insulator because of its low cost, weather-resistance and fairly good electrical performance. However, for certain projects PVC may not meet the requirements, which will make one of these other materials a necessary upgrade.