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Anatomy of a hydro pole

This illustration shows basic equipment found on hydro poles. Not all poles have all this equipment — they vary according to location and the service they provide.

Basic equipment on a hydro pole.

  1. Insulators prevent energized wires from contacting each other or the pole.
  2. Crossarms hold wires up on the pole.
  3. Transformers convert higher voltage electricity from primary lines to lower voltages for homes and businesses.
  4. Guy wires stabilize the poles.
  5. Neutral wires are below the transformer. They balance out the amount of electricity on the system by feeding back to the substation.
  6. Primary wires are at the top of a pole and carry up to 33,000 volts from a substation.
  7. Cutouts act like a fuse: they open when there’s a problem with the line.
  8. Surge arrestors protect the pole and the equipment from lightning strikes.
  9. Secondary wires carry lower voltage electricity up to 240 volts from transformers to homes and businesses.
  10. Phone and cable wires are typically the lowest wires. We usually don’t own these wires, but we share space on our poles.
  11. A 7-digit barcode tag is posted at eye level and identifies the pole’s location with global positioning. Knowing the location of every pole helps us track their lifecycles and respond to outages more quickly.