Answer from Ningbo Changshi: Bends are the primary cause of tension increase and are where the risk of cable damage is highest. Pulling around a bend is governed by the "capstan effect," which exponentially multiplies the tension.

The pulling tension formula for a bend is:

Tout=Tin×e(μ×θ)

Where:

• Tout is the tension leaving the bend.

• Tin is the tension entering the bend.

• e is the base of the natural logarithm (approximately 2.718).

• μ is the coefficient of friction.

• θ (theta) is the angle of the bend in radians.

This formula shows that small changes in the coefficient of friction or the bend angle can lead to a dramatic increase in tension. A 90-degree bend, for example, is equal to 2π radians. For this reason, professional cable pulling software is essential for accurately planning pulls that have multiple bends, slopes, or long distances, as it can model the cumulative tension from each section. We emphasize the use of professional tools and planning to manage this critical aspect of a project.