Selecting the right pulley is vital for the safety and success of a cable installation. The three most important factors to consider are:

• Sheave Diameter: The diameter of the pulley's sheave is critical. It should be large enough to prevent the cable from bending too tightly. A general rule of thumb is that the sheave's diameter should be at least 15 to 20 times the cable's diameter to avoid micro-bends and potential damage, especially with fiber optic or high-voltage cables.

• Working Load Limit (WLL): The pulley must have a Working Load Limit (WLL) that is greater than the maximum anticipated pulling force. The WLL is calculated using a safety factor, typically 4:1, to ensure the pulley does not fail under the load.

• Sheave Material: Pulleys are commonly made from aluminum alloy or high-strength nylon. Nylon sheaves are a preferred choice for modern conductors and cables because they have a smooth, non-conductive surface that minimizes friction and protects the cable jacket.