Circuit Protection

Providing protection and consistency to electrical circuits are the two primary functions of a circuit protection device. By adding a weak link into an electrical circuit, it protects against short circuit, excessive current, and any other electrical fault. It automatically disconnects the supply and break the weak link as soon as an overload is detected. A fault or overload happens in an electrical circuit when the electron that flows through a conductor is excessive. Going over the allowed safe level of amperage that passes through the wire is dangerous. Additionally, a wire’s insulation can also ground a circuit that can lead to chafing. It is during situations like this that a circuit protection device is vital.

Types

There are two general types of circuit protection devices: fuses and electro-mechanical circuit breakers.

  1. Fuses are classified into slow-blow, fast-blow, and semiconductors. Each category has its own way of responding to fault currents. Semiconductor and fast-blow fuses are the quickest to respond, while slow-blow fuses are equipped with spring-loaded mechanisms. They can manage temporary current surges that go over the fuse’s current rating. Also, slow-blow fuses have built-in time delay features, so they only disconnect circuits when the excess or overcurrent remains constant in the supply line or when current overload conditions are repeated.
    Fuses are equipped with wires that can easily melt. If excessive current gets in through these fuses, their wires get heated up and melt until the circuit breaks.
  2. Electro-mechanical circuit breakers are divided into two primary sub-categories: thermally actuated and magnetically actuated. Thermal devices use mechanical motion in unlatching a pair of contacts. Current-sensitive magnetic devices unlatch contacts through magnetic fields generated by coils. They are ideal for circuit protection.
    Thermal-mags devices are those that use both thermal and magnetic technologies in one device. A good example for this would be the circuit breakers used in a typical house.

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Parts from Circuit Protection Category

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LU9MR1C from Schneider Electric
Schneider Electric

PRE-WIRED CONNECTOR, MOTOR STARTER; For Use With:TeSys U Direct On Line Motor Starter; Accessory Type:Control Terminal Block; Product Range:- RoHS Compliant: Yes

QBPAF from Square D By Schneider Electric
Square D By Schneider Electric

HANDLE PADLOCKING DEVICE, CKT BREAKER; For Use With:Schneider PowerPact Q-Frame Circuit Breakers; Accessory Type:Handle Padlocking Device; Product Range:PowerPact Series RoHS Compliant: Yes

S29386 from Square D By Schneider Electric
Square D By Schneider Electric

SHUNT TRIP KIT; For Use With:Thermal Magnetic Circuit Breakers (H / J Frame); Accessory Type:Shunt Trip Kit; Product Range:PowerPact Series; Operating Voltage:120VAC RoHS Compliant: Yes

S29450 from Square D By Schneider Electric
Square D By Schneider Electric

AUXILIARY SWITCH; For Use With:Thermal Magnetic Circuit Breakers (H / J Frame); Accessory Type:Auxiliary Switch; Product Range:PowerPact Series; Features:1A / 1B Standard Contacts RoHS Compliant: Yes

S32631 from Square D By Schneider Electric
Square D By Schneider Electric

HANDLE PADLOCKING DEVICE, CKT BREAKER; For Use With:Schneider PowerPact M/P/L/R-Frame Circuit Breakers; Accessory Type:Handle Padlocking Device; Product Range:PowerPact Series RoHS Compliant: Yes

S33659 from Square D By Schneider Electric
Square D By Schneider Electric

SHUNT TRIP, CIRCUIT BREAKER; For Use With:Schneider PowerPact M/P/R-Frame Circuit Breakers; Accessory Type:Shunt Trip; Product Range:PowerPact Series RoHS Compliant: Yes

4028356450K from Square D By Schneider Electric
Square D By Schneider Electric

DOOR HINGE KIT, CIRCUIT BREAKER; For Use With:Schneider QO/HM Series Circuit Breakers; Accessory Type:Door Hinge Kit; Product Range:- RoHS Compliant: Yes

9421LS13 from Square D By Schneider Electric
Square D By Schneider Electric

LONG SHAFT, CIRCUIT BREAKER MECHANISM; For Use With:9421LG7 Series or LJ7 Series Circuit Breaker Operating Mechanisms; Accessory Type:Long Shaft; Product Range:9421L Series RoHS Compliant: Yes

1-1423696-6 from Potter&brumfield - Te Connectivity
Potter&brumfield - Te Connectivity

BOOT SEAL, THERMAL CKT BREAKER, CLEAR; For Use With:AMP W54 Series Thermal Circuit Breakers; Accessory Type:Boot Seal; Product Range:W54 Series RoHS Compliant: Yes

44-768 from Ideal
Ideal

CIRCUIT BREAKER LOCKOUT SYSTEM; For Use With:Square D NQO & Other Breaker; Accessory Type:Lockout System; Product Range:- RoHS Compliant: NA

LD10 from Weidmuller

LD10

View Details or Pricing
Weidmuller

LOCK-ON/LOCK-OFF DEVICE, CIRCUIT BREAKER; For Use With:Weidmuller BR/SU Series Miniature Circuit Breaker Bus Bars; Accessory Type:Lock-on, Lock-off Device; Product Range:- RoHS Compliant: Yes

M9A26476 from Schneider Electric
Schneider Electric

SHUNT TRIP RELEASE, CIRCUIT BREAKER; For Use With:Schneider Multi 9 Series Miniature Circuit Breakers; Accessory Type:Shunt Trip Release; Product Range:Multi 9 Series RoHS Compliant: Yes

M9A26477 from Schneider Electric
Schneider Electric

SHUNT TRIP RELEASE, CIRCUIT BREAKER; For Use With:Schneider Multi 9 Series Miniature Circuit Breakers; Accessory Type:Shunt Trip Release; Product Range:Multi 9 Series RoHS Compliant: Yes

M9A26478 from Schneider Electric
Schneider Electric

SHUNT TRIP RELEASE, CIRCUIT BREAKER; For Use With:Schneider Multi 9 Series Miniature Circuit Breakers; Accessory Type:Shunt Trip Release; Product Range:Multi 9 Series RoHS Compliant: Yes

M9A26924 from Schneider Electric
Schneider Electric

AUXILIARY CONTACT, CIRCUIT BREAKER; For Use With:Schneider Multi 9 Series Miniature Circuit Breakers; Accessory Type:Auxiliary Contact; Product Range:Multi 9 Series RoHS Compliant: Yes

M9A26927 from Schneider Electric
Schneider Electric

FAULT INDICATING CONTACT, CIRCUITBREAKER; For Use With:Schneider Multi 9 Series Miniature Circuit Breakers; Accessory Type:Fault Indicating Contact; Product Range:Multi 9 Series RoHS Compliant: Yes

M9A26929 from Schneider Electric
Schneider Electric

FAULT INDICATING CONTACT, CIRCUITBREAKER; For Use With:Schneider Multi 9 Series Miniature Circuit Breakers; Accessory Type:Double Open/Closed or Fault Indicating Contact; Product Range:Multi 9 Series RoHS Compliant: Yes

M9A26946 from Schneider Electric
Schneider Electric

SHUNT TRIP RELEASE, CIRCUIT BREAKER; For Use With:Schneider Multi 9 Series Miniature Circuit Breakers; Accessory Type:Shunt Trip Release w/ Auxiliary Contact; Product Range:Multi 9 Series RoHS Compliant: Yes

M9A26947 from Schneider Electric
Schneider Electric

SHUNT TRIP RELEASE, CIRCUIT BREAKER; For Use With:Schneider Multi 9 Series Miniature Circuit Breakers; Accessory Type:Shunt Trip Release w/ Auxiliary Contact; Product Range:Multi 9 Series RoHS Compliant: Yes

M9A26948 from Schneider Electric
Schneider Electric

SHUNT TRIP RELEASE, CIRCUIT BREAKER; For Use With:Schneider Multi 9 Series Miniature Circuit Breakers; Accessory Type:Shunt Trip Release w/ Auxiliary Contact; Product Range:Multi 9 Series RoHS Compliant: Yes

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