What happens to a distribution pole before it fails, after deflecting?

When a distribution pole undergoes deflection due to external forces like wind or the weight of electrical lines, it may initially bend but typically does not return to its original shape. This phenomenon is known as plastic deformation.

As the pole continues to experience stress beyond its elastic limit, it will develop cracks, particularly at weak points or areas where the material is under greater strain. These cracks can spread as the stress continues to act on the pole, ultimately compromising its structural integrity.

The correct answer reflects the progressive nature of failures in materials. While a pole may bend, it is the formation of cracks that is often the precursor to a complete failure, such as snapping or breaking. This understanding is crucial for anticipating maintenance needs and ensuring safety in electrical distribution systems.

The other options, while related to the failure process, do not accurately describe the mechanism that occurs before catastrophic failure. Snapping or breaking implies a sudden failure, while permanent bending does not typically lead to functional failure without the critical precursor of cracking. Cracking is a more indicative early-stage failure that signals the need for intervention.