What is a Protection Device? Different types of Protection Devices

Protection devices for electrical circuits accomplish two main functions namely consistency as well as protection. Protection is assured through detaching power supply in a circuit through overcurrent protection, which removes fire hazards and electrocution. Additionally, the accurate protection may be required to obey with organization principles for some products. Designers must take time to know the different protection devices for circuits. Protection devices used to protect circuits from extreme voltages or currents. This article discusses what is a protection device, and types of protection devices used in electrical and electronic circuits.

What is a Protection Device?

The circuit protection device is an electrical device used for preventing an unnecessary amount of current otherwise a short circuit. To ensure the highest security, there are many protection devices available in the market which offers you a total range of protection devices for circuits such as a fuse, circuit breakers, RCCB, gas discharge tubes, thyristors, and more.

Different types of Protection Devices

The different types of circuit protection devices examples include the following.

  • Fuse
  • Circuit Breaker
  • PolySwitch
  • RCCB
  • Metal Oxide Varistor
  • Inrush Current Limiter
  • Gas Discharge Tube
  • Spark Gap
  • Lightning Arrester


In electrical circuits, a fuse is an electrical device used to protect the circuit from overcurrent. It consists of a metal strip that liquefies when the flow of current through it is high. Fuses are essential electrical devices, and there are different types of fuses available in the market today based on specific voltage and current ratings, application, response time, and breaking capacity.

The characteristics of fuses like time and current are selected to give sufficient protection without unnecessary disruption. Please refer the link to know more about: Different Types of Fuses and Its Applications.

Circuit Breaker

A circuit breaker is one kind of electrical switch used to guard an electrical circuit against short circuit otherwise an overload which will cause by excess current supply. The basic function of a circuit breaker is to stop the flow of current once a fault has occurred. Not like a fuse, a circuit breaker can be operated either automatically or manually to restart regular operation.

Circuit breakers are available in different sizes from small devices to large switch gears which are used to protect low current circuits as well as high voltage circuits. Please refer the link to know more about: Types of Circuit Breaker and Its Importance.

Poly Switch or Resettable Fuse

A resettable fuse is a passive electronic component used for protecting electronic circuits from over-current mistakes. This device is also called as a poly switch or multi fuse or poly fuse. The working of these fuses is same as PTC thermistors in particular situations, however, work on mechanical transforms instead of charge-carrier-effects within semiconductors.

Resettable Fuses are used in several applications like power supplies in computers, nuclear or aerospace applications where substitution is not easy.


The RCD-residual current device (or) RCCB- residual current circuit breaker is a safety device which notices a problem in your home power supply then turns OFF in 10-15 milliseconds to stop electric shock. A residual current device does not give safety against short circuit or overload in the circuit, so we cannot change a fuse instead of RCD.

RCDs are frequently incorporated with some type of circuit breaker like an MCB (miniature circuit breaker) or a fuse, which guards against overload current in the circuit. The residual current device also cannot notice a human being due to by mistake touching both conductors at a time.

These devices are testable as well as resettable apparatus. A test button securely forms a tiny leakage condition; along with a reset button again connects the conductors after an error state has been cleared.

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