page_title: Fuse (electrical)
section_title: High voltage fuses
hierarchical_section_title: Fuse (electrical) / High voltage fuses
caption_attribution_description: English: Pole mount transformer protected by three fusible cutouts. One fuse element (white barrel) has blown and is hanging down. 12.47 kV 3 Phase distribution line, at Gardiner Dam, Saskatchewan, CanadaРусский: Трансформатор на столбе защищён тремя плавкими предохранителями. Один предохранитель (белый бочонок слева) перегорел и свисает вниз. Трёхфазная ЛЭП 12,47 кВ на плотине Гардинер (Саскачеван, Канада)
context_page_description: In electronics and electrical engineering, a fuse is an electrical safety device that operates to provide overcurrent protection of an electrical circuit. Its essential component is a metal wire or strip that melts when too much current flows through it, thereby stopping or interrupting the current. It is a sacrificial device; once a fuse has operated it is an open circuit, it must be replaced or rewired, depending on type.
  Fuses have been used as essential safety devices from the early days of electrical engineering. Today there are thousands of different fuse designs which have specific current and voltage ratings, breaking capacity and response times, depending on the application. The time and current operating characteristics of fuses are chosen to provide adequate protection without needless interruption. Wiring regulations usually define a maximum fuse current rating for particular circuits. Short circuits, overloading, mismatched loads, or device failure are the prime or some of the reasons for fuse operation.
  A fuse is an automatic means of removing power from a faulty system; often abbreviated to ADS.
context_section_description: Fuses are used on power systems up to 115,000 volts AC.  High-voltage fuses are used to protect instrument transformers used for electricity metering, or for small power transformers where the expense of a circuit breaker is not warranted. A circuit breaker at 115 kV may cost up to five times as much as a set of power fuses, so the resulting saving can be tens of thousands of dollars.
  In medium-voltage distribution systems, a power fuse may be used to protect a transformer serving 1–3 houses.   Pole-mounted distribution transformers are nearly always protected by a fusible cutout, which can have the fuse element replaced using live-line maintenance tools.
  Medium-voltage fuses are also used to protect motors, capacitor banks and transformers and may be mounted in metal enclosed switchgear, or (rarely in new designs) on open switchboards.
caption: A set of pole-top fusible cutouts with one fuse blown, protecting a transformer - the white tube on the left is hanging down
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