Course ID
TDA21

COURSE DESCRIPTION

This training program is designed to familiarize students with the various types of weights and tensions associated with rigging in line work. The safety factor for a job that includes rigging is also covered. The procedures and concepts presented assume a familiarity with basic electrical theory and transmission and distribution systems.

COURSE GOALS

• Explain the difference between static force loads and dynamic force loads.
• Explain how to determine the weight of static force loads and dynamic force loads.
• Define and explain line tension, bisect tension, and guy tension, and calculate these tensions for a given job.
• Define the term “safety factor” in terms of rigging, and apply a safety factor to plan safe rigging.

SUBJECTS AND OBJECTIVES

Rigging Forces and Tensions – Part 1

• Identify and describe two types of loads involved in rigging for line work.
• Describe how to determine the weight exerted by a conductor on an insulator.

Rigging Forces and Tensions – Part 2

• Define the term “line tension,” and explain how to determine the line tension exerted by a conductor.
• Define the term “bisect tension,” and describe how bisect tension can be determined by measuring distances.

Rigging Forces and the Safety Factor

• Describe how to use a bisect tension formula to determine the bisect tension exerted on a corner pole.
• Describe how to determine the approximate bisect tension exerted on a corner pole by finding the approximate angles of the line at the pole and using a “rule-of-thumb” chart.
• Define the term “guy tension,” and describe how to determine the approximate guy tension required to hold against line or bisect tension.
• Define the term “safety factor” in terms of rigging for line work, and describe how to calculate the safety factor for a given job.

Weight and Tension Calculations

• Describe how conductor weight is affected when a conductor is raised or lifted to a new pole.
• Describe how to determine the weight and bisect tension exerted by conductors when they are moved to a new pole.
• Describe how to determine the guy tension needed to offset the bisect tension exerted by conductors after they are moved to a new corner pole.
• Explain how to establish a safety factor of five for the rigging used to lift a conductor and move it to a new pole.