What is the purpose of a 'bend radius' guide or formula?

• A. To measure the diameter of the conduit.
• B. To ensure turns are not too sharp, protecting insulation and meeting code requirements.
• C. To set the maximum cable length.
• D. To decide the color of cable jackets.

Answer: (B)

Understanding bend radius helps ensure cables survive bends without damage. A bend radius guide or formula sets the minimum curve a cable or conduit can be bent, so turns aren’t too sharp. If you bend closer than this minimum, insulation can crack or wear, conductors can be stressed or damaged, and heat or moisture problems can develop over time. Keeping to the recommended radius also helps meet safety and code requirements, since many codes specify minimum bend radii to protect the cable and ensure reliable performance. In practice, you apply the bend radius by planning the run so the curve meets that minimum size, using the cable’s outer diameter (or a specified multiple) to determine the exact minimum radius. The other options don’t reflect this purpose—bend radius isn’t about measuring diameter, setting total cable length, or choosing jacket color.