When installing electrical nonmetallic tubing, it must be securely fastened at distances not exceeding?

In the context of installing electrical nonmetallic tubing, the requirement is that it must be securely fastened at intervals that do not exceed a specified distance to ensure safety and maintain the integrity of the installation. The correct answer indicates that this fastening must occur at distances not exceeding 3 feet.

This requirement is based on the National Electrical Code (NEC) guidelines, which establish standards for electrical installations, including the support of nonmetallic raceways. Proper support prevents sagging and potential damage to the tubing, safeguarding the conductors within from mechanical stress and environmental factors. Fastening at these intervals also aids in maintaining the tubing's position, ensuring that it operates effectively without posing risks to the electrical circuit it encases.

While longer distances can be applicable for some other types of conduits or raceways under different circumstances, for electrical nonmetallic tubing, shorter distances are mandated to provide maximum stability and protection against hazards such as physical damage.