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.
- 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.