When installing ENT, what must be ensured according to standards?

Ensuring that ENT (Electrical Nonmetallic Tubing) is protected from physical damage is crucial due to the inherent characteristics of the material. ENT is typically made of PVC, which, while lightweight and flexible, can be susceptible to impact and other forms of physical harm. Protecting it from physical damage helps maintain its integrity and ensures that it continues to function effectively in protecting electrical conductors.

Physical damage can compromise the electrical system's safety by exposing wires to potential hazards. Therefore, following standards that stipulate the need for protection against physical damage is essential in the proper installation of ENT, ensuring that the system remains safe, durable, and compliant.

The other choices touch on various aspects of installation but do not directly address the critical need for physical protection during the installation process. For instance, while painting ENT can help with corrosion in some contexts, it is more relevant to metallic materials. Sealing connections tightly is important for electrical integrity but is not as critical in the context of ENT as ensuring it is safeguarded from impacts or crush damages. Installing ENT without any fittings is not a standard requirement, as fittings are often necessary to create proper connections and maintain the integrity of the installation.