A squirrel is utility shorthand for a fault caused by an animal climbing on transformers, bushings or bus and bridging phase to earth. Squirrels, birds, snakes and possums together cause a large share of distribution outages, and the classic evidence is a scorched carcass under a pole transformer after a trip. Wildlife guards, bushing covers and covered jumpers are the defence.
Feeder 3 trip was another squirrel, found it under the first pole outside the sub, the bushing guard was missing.
Utilities track animal contact as a named outage cause, and squirrels top the list in much of North America.
Also heard as
- animal contact
- squirrel outage
- critter fault
Related terms
Flashover
Disruptive discharge over or around insulation that creates a short circuit through the air.
Trip
To open a circuit breaker automatically through its protection, or to order a breaker open by command.
Earth fault
Fault in which a live conductor makes unintended contact with earth or with earthed metalwork.