ISC Medium Rigging Pulley for Rope up to 20 mm, 150 kN

The ISC medium rigging pulley takes rope up to 20 mm and carries a 150 kN rating, which makes it a strong, all-round redirect for 5/8 and 3/4 inch rigging lines. The blue frame with green wheel sets it apart from the other ISC sizes in the bag.

Where it fits in a rigging system

A rigging pulley replaces a natural crotch as the redirect for your lowering line. Hang it from a rated sling on a sound anchor above the work, run the rope through the sheave, and take it down to a lowering device at the base. The ground worker gets steady, predictable friction from the device instead of uneven crotch friction.

Size it to the rope and the load. The pulley and anchor see roughly twice the rope tension because the line pulls from both sides, and pieces that fall before the catch add shock load. Keep drops short and let the rope run slightly to soften the stop. Check ISC's published ratings before sizing it to a job.

Because it covers both 5/8 and 3/4 inch lines, many crews treat the medium as their do-everything rigging pulley.

Inspection and care

Spin the sheave by hand and make sure it runs smoothly with no wobble. Look for cracks, bent side plates, wear grooves, and loose fasteners. Retire a pulley that has been dropped from height onto a hard surface or overloaded. Compare models in our rigging blocks section.

Rigging forces are dynamic and can be several times the weight of the piece. Follow the manufacturer's ratings and ANSI Z133, inspect every component before the job, and keep rigging work to trained crews.