What is the minimum tensile strength that should be verified for a pull string?

The minimum tensile strength for a pull string should be verified to ensure that it can handle the mechanical stresses applied during the installation of communication cables. The value of 330 N (75 lbf) is often referenced as a standard for pull strings in various installations because it provides a balance between sufficient strength and practicality in installation scenarios. This tensile strength is designed to ensure that the pull string can withstand the forces exerted when pulling cables through conduit or over distances without breaking, thus facilitating a successful installation process.

Using a tensile strength that is too low could result in the pull string failing during use, which could lead not only to installation delays but also to potential damage to the cables being installed. On the other hand, choosing a strength that exceeds this minimum requirement (such as 440 N or higher) may not be necessary for typical installations and could increase costs without providing significant benefits.

By adhering to the established minimum tensile strength of 330 N (75 lbf), installers can ensure reliable performance without incurring unnecessary expenses or complications associated with handling heavier, overly robust pull strings.