Wire Rope: Maintaining Safety
January 23, 2020 | Blog | Crane Operator | Cranes | Inspection | Josh Duckett | Safety Training | Training
Is your wire rope safe?
Did you know even a small kink in your cable can decrease it’s breaking strength significantly? Inspecting the wire rope on your crane frequently and thoroughly will help prevent a catastrophic event. If your cable has broken wires, kinks, bird caging, or is untwisting, it’s time to pause and get a new cable.
Each day that the crane is running, OSHA (§ 1926.1413) requires that a shift inspection be done.
All running and standing rope must be inspected. Booming down or untwisting of the wire is not necessary to complete a shift inspection.
In this picture, we have included what you want to be on the lookout for during wire rope inspection. If you happen to find broken wires, please refer to OSHA standard 1926.1413 to make sure your crane is in compliance. In running rope, six random broken wires in one rope lay are cause for removal. Three broken wires in the same strand in one rope lay are cause for removal. For rotation resistant rope, it’s two randomly distributed broken wires in six rope diameters or four randomly distributed broken wires in thirty rope diameters.
A great way to remember rotation resistant rope is “Two six-packs by four-thirty.”
When inspecting standing wire or pendants, two or more broken wires in one rope lay is cause for removal. At the end connection, you’re allowed one broken wire; two broken wires at an end connection is cause for removal. If all checks out and your rope is in good shape, use your micrometer. Make sure that your rope diameter doesn’t have a reduction of more than 5% from a nominal diameter. If it doesn’t check out and you find broken wires, kinks, bird caging, etc. you may cut the damaged portion of the wire rope. You can then use the remaining undamaged rope. If you do need to cut the rope, make sure you will still have two wraps left on the drum when the block is at its lowest point. Joining two lengths of wire rope by splicing them together is prohibited. Help keep your job site safe and check your cables daily to prevent a catastrophic event.