Distribution System Training

The objective of this module is to demonstrate and discuss the features of overhead distribution systems.

After completion of this module, and associated workbook, the participant should be able to understand the following concepts, and apply them in day-to-day work practice.

• Advantages and disadvantages of overhead construction
• The use of bare conductors and covered conductors
• Conductor supports i.e. lattice towers, steel, concrete and wood poles
• Conductor support arrangements on wood poles
• Types of insulators
• Multiple circuits on poles
• Mounting equipment on poles
• The need for guy wires
• Grounding the neutral conductor
• The characteristics of copper and aluminium conductors (ACSR)
• Standard conductor sizes (AWG)
• “Circular mil” units of measuring conductor and strand sizes
• Manufacturer’s tables for solid and stranded conductors indicating weight tensile strength, and ohmic resistance
• The use of ampacity tables to indicate conductor current limits
• The effect of conductor material, ambient temperature, wind velocity, and current flow on ampacity
• Factors affecting line sag, including conductor tension, conductor weight, ice loading, ambient temperature, wind velocity, and conductor current
• Primary feed arrangements between the distribution bus and the primary feeder
• Line dead end support
• Line taps to feed customers from primary feeder
• Connections to primary terminals of distribution transformers
• Secondary wiring arrangements to customer’s service entrance