What information is required before a cable rigging chart can be used?

• A. The ambient temperature.
• B. The cable size.
• C. The ambient temperature and the cable size.
• D. The weather conditions at the site.

Answer: (C)

The information needed to use a cable rigging chart is ambient temperature and the cable size, because both factors directly affect how a cable lengthens or shortens under load. The chart is organized by temperature because metal expands with heat and contracts when cool, changing tension and elongation for a given preload. It’s also organized by cable diameter because different sizes have different stiffness and stretch characteristics. Without knowing the actual temperature and the exact cable size, you can’t select the correct values on the chart, and using the wrong line could lead to improper tension or deflection. Weather conditions aren’t used directly beyond the ambient temperature you observe at installation, so only those two pieces of information are essential.