Working Load Limit (WLL) – The Working Load Limit is the maximum load which should ever be applied to the cable, even when new or when the load is evenly distributed – straight line pull only. Avoid side loading. All ratings are based upon regular environmental conditions; conditions; attention must be given to unusual conditions such as severe temperature, chemical solutions or vapors, prolonged immersion in salt water, etc.

Proof Test Load (Proof Load) – The term “Proof Test” assigns a quality control test applied to the product for exclusive function of exposing flaws in material or build. The Proof Test Load (normally 2x the WLL) is load which the cable underwent & sustained without malformation when new and under laboratory test conditions. The Proof Test Load does not mean that the WLL should ever be exceeded.
Breaking Strength – Breaking Strength is the average force at which the wire rope, in the condition it would leave the factory, has been found by representative testing to break, when a constantly increasing force is applied in direct line to the product at a uniform rate of speed on a stander pull testing machine. Proof testing to twice the WLL does not apply to hand-spiced slings. Remember: Breaking Strength, when published, where obtained under controlled laboratory conditions. Listing the Breaking Strength does not mean the Working Load Limit should ever be exceeded. Do not use breaking strength as a criterion for service or design purposes. Refer to the Working Load Limit instead.
Design Factor – An industry term usually computed by dividing the Breaking Strength by the WLL and generally expressed as a ration (ex: 7:1).
Shock Load – A load resulting from rapid change of movement, such as impacting, jerking or swinging of a stack load. Sudden release of tension is another form of shock loading. Shock loads are generally significantly greater than static loads. Any shock loading must be considered when selecting the item for use in a system. Avoid shock loads as they may exceed the Working Load Limit.