Glossary

Glossary

  • A

  • Animal GuardAnimal Guard: Helps prevent power outages caused by animal contact with electrical equipment.
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  • C

  • Cable ChamberCable Chamber: A below-grade opening to the underground system that facilitates the installation and removal of feeders, and provides access to cables requiring inspection and repair. They are located under sidewalks and roadways. Depending on location and construction type, life expectancy can range from 40 to 50 years.
  • Civil WorkCivil Work: The installation of the infrastructure which will house the electrical cables and equipment. Examples of this would be duct structures, cable chambers, vaults, tap boxes, foundations, handwells and poles.
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  • D

  • Distribution System: Is comprised of the wires, poles, transformers, substations and other equipment used to deliver electricity to customers. The distribution system delivers power at voltage levels that can be used in homes and businesses.
  • Distribution Transformer: A large piece of equipment required to reduce the distribution voltage to secondary voltage to match the customers’ appliances and equipment voltages.
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  • E

  • Electrical PhaseElectrical Phase: This work begins after the civil work.  It involves replacing electrical equipment such as wires and cables.  This phase often requires planned outages to transfer the old supply to the new distribution system.
  • Elbow JointElbow Joint: Used to terminate cables in vaults and in padmounted transformers. 
  • Electrical GridElectrical Grid: An interconnected network for delivering electricity from suppliers to consumers.
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  • F

  • Feeder: A distribution circuit carrying power from a substation.  The heavy high-voltage cable (circuit) supplies the distribution transformers and emanates from the station via ducts beneath city streets to the designated service areas.
  • Feeder Reliability Program:  A program dedicated to repairing feeders that experience higher than average power interruptions
  • fuseFuse: Protects the distribution line from overloading.  Acts by melting during overloading or faults, breaking the circuit.  Is similar to fuses found in fuse boxes in homes.
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  • H

  • Handwell: A small metal plate covering underground wiring for streetlights. These are usually located three to four feet from an electrical pole. 
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  • J

  • Joint Use Trenching: An efficient and integrated trenching approach in which utilities share underground duct space.
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  • L

  • Elbow JointLead Cable: Paper insulated lead-covered underground cables that are being phased out globally.
  • Lightning Arrester: A protective device installed on the primary (high voltage) side of the distribution transformer.  It’s used to prevent excessive over-voltage surges across the transformer, caused by lightning strikes or live-line switching.
  • Load/Capacity GrowthLoad/Capacity Growth: Upgrading the existing system to handle new or existing customer loads or a higher connection capacity.
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  • O

  • Outside Utility EquipmentOutside Utility Equipment: Equipment (e.g. poles) that house similar parts, such as wiring, with other utilities (e.g. phone and cable companies)
  • Overhead WiresOverhead Wires: Essentially a large diameter cable carrying power from a terminal or municipal station to customers using poles as supports.
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  • P

  • Planned Power Interruptions/OutagesPlanned Power Interruptions/Outages: Power outages coordinated in advance to safely transfer the electrical services over to the new distribution system.
  • Property Restoration Phase: The final phase in which property is returned to its preconstruction state. Grass areas are sodded, asphalt driveways are replaced from sidewalk to curb and interlock is removed and replaced. This work is done outside of the winter months.
  • PolesPoles: Poles are constructed primarily of wood or concrete and provide support for all the “overhead” wires, switches and transformers throughout the city. Most poles are over thirty feet high and provide a “safety” barrier for the public.
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  • R

  • Rear Lot Conversion: The process of relocating aging electrical equipment located in backyards to the front of properties to improve access for maintenance.
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  • S

  • Secondary CablesSecondary Cables (or Mains): Underground low voltage (<750 volt) cables which are connected to the secondary side (low voltage) of the distribution transformer and delivers the current to customers.
  • SubstationSubstation: A subsidiary station where voltage is transformed from high to low or the reverse using transformers.
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  • T

  • Transformer VaultTransformer Vault:  Is a large room used to house submersible transformers, switches and protective equipment (fuses and surge arresters).  Transformer vaults can also be used to provide adequate working space for employees to install and remove equipment or conduct inspections and maintenance duties. This equipment can be below-grade as seen in the photo, or street level.
  • Tree TrimmingTree Trimming: A preventive maintenance program that cuts back trees to prevent branches from damaging or blowing into overhead lines and causing outages.
  • Tree WireTree Wire: A covered conductor used in heavily treed areas to provide some protection form momentary tree limb contact. Should not be considered to be insulated for physical contact.
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  • U

  • Underground Direct Buried Cable: Cable manufactured without an outer protective layer of polyethylene and buried without any form of casing. Cables have a life expectancy of approximately 25 to 40 years.
  • Underground Distribution System Cable:Underground Distribution System Cable: Underground cable that is encased in duct.  This cable must be replaced when demonstrating signs of degradation.
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