MCBs

MCBs, or miniature circuit breakers, are a type of switch used to automatically turn off electrical circuits during abnormal conditions. MCBs often replace fuses in low voltage electrical circuits as they can be more reliable, much more sensitive and are resettable.


How an MCB Works


When continuous overcurrent flows through an MCB, a bimetallic strip is heated and causes it to bend. This bending of the bimetallic strip releases a mechanical latch opening the contacts and turning off the MCB, thereby stopping the current to flow in the circuit. To restart the flow of current the MCB must be manually turned on. This mechanism protects the MCB from faults arising due to overcurrent or overload and is intended to prevent the accidental overloading of the cable in a no-fault situation. The speed of the MCB tripping will vary with the degree of the overload. This is usually achieved by the use of a thermal device in the MCB. The second characteristic is the magnetic fault protection, which is intended to operate when the fault reaches a predetermined level and to trip the MCB within one-tenth of a second. The level of this magnetic trip gives the MCB its type characteristic.


MCBs are used to perform many functions such as local control switches, isolating switches against faults and overload protection devices for installation or specific equipment or appliances.


MCB Types


MCBs have three common types for circuit protection in residential, commercial and industrial applications. The use is classified by a type, which determines the tripping characteristics of the MCB:


Type B - trips between 3 and 5 times the load current


This type will trip instantly at a rate of three to five times its rated current. These are normally used for resistive or small inductive loads where switching surges are very small. Therefore, these are suitable for residential or light commercial installations.


Type C - trips between 5 and 10 times the full load current


This type will trip instantly at a rate of five to ten times its rated current. These are normally used for high inductive loads where switching surges are high such as small motors and fluorescent lighting. In such cases, type C MCBs are preferred to handle higher value of short circuit currents. Therefore, these are suitable for highly inductive commercial and industrial installations.


Type D - trips between 10 and 20 times the full load current


This type will trip instantly at a rate of ten to twenty-five times its rated current. These are normally used for very high inductive loads where high inrush current is very frequent. These are suitable for specific industrial and commercial applications. The common examples of such applications include x-ray machines, UPS systems, industrial welding equipment, large winding motors, etc.


How to select a suitable MCB for the application?


Focus on 3 main points to choose the right MCB for the electrical circuit


  1. Ampere rating

  2. Short circuit breaking capacity

  3. Application type

...
Read more Read less

Filters

Viewing 21 - 40 of 2392 products
Results per page
Description Price Number of Poles Current Rating Model Number Range Series Tripping Characteristics Rated AC Voltage Rated DC Voltage Breaking Capacity Mounting Style Length Width Depth Application
RS Stock No. 535-6011
Mfr. Part No.2CDS271001R0255
BrandABB
€16.65
Each
units
1 25 A - System M Pro S200 Type B 253 V 72V 10 kA - 88mm 17.5mm 75.8mm -
RS Stock No. 791-3219
Mfr. Part No.A9F53306
€76.99
Each
units
3 6 A - Acti 9 iC60H Type B 440 V, 12 → 133 V, 220 → 240 V, 380 → 415 V 100 → 133V 10 kA DIN Rail 85mm 54mm 78.5mm -
RS Stock No. 864-4374
Mfr. Part No.PLSM-D32/2-MW
€57.28
Each
units
2 32 A - xPole PLSM Type D 230 V ac 48V 10 kA - 35mm 80mm 75mm -
RS Stock No. 125-1471
Mfr. Part No.1492-SPM2C060
€59.80
Each
units
2 6 A - 1492 1492SPM Type C 277 V, 480 V 96V 10 kA - 35mm 75mm 88mm General Purpose
RS Stock No. 622-0014
Mfr. Part No.5SY4102-7
BrandSiemens
€21.91
Each
units
1 2 A - Sentron 5SY4 Type C 230 V, 400 V - 10 kA - 89.8mm 17.6mm 76.4mm -
RS Stock No. 825-5719
Mfr. Part No.P1MB2PC04
BrandLovato
€38.65
Each
units
2 4 A - ModuLo P1MB Type C 230 V, 400 V 80V 10 kA - 86.5mm 36mm 79.52mm -
RS Stock No. 734-9260
Mfr. Part No.A9F77620
€61.29
Each
units
1 + N 20 A - Acti 9 iC60N Type C 100 → 130 V, 12 → 60 V, 220 → 240 V, 230 V - 6 kA - - 36mm - -
RS Stock No. 791-3354
Mfr. Part No.A9F54240
€51.95
Each
units
2 40 A - Acti 9 iC60H Type C 440 V, 12 → 133 V, 220 → 240 V, 380 → 415 V 100 → 133V 10 kA DIN Rail 85mm 36mm 78.5mm -
RS Stock No. 849-6594
Mfr. Part No.EUC3P20C
BrandEuropa
€21.67
Each
units
3 20 A - EU EUC Type C 230/400 V - 10 kA - 54mm 78mm 87mm -
RS Stock No. 124-3020
Mfr. Part No.EMBH106
BrandEaton
€17.44
Each
units
1 6 A - MEMShield EMBH Type B 230 V, 240 V 48V 10 kA - 18mm 75mm 80mm Commercial Buildings
RS Stock No. 791-3332
Mfr. Part No.A9F54206
€51.81
Each
units
2 6 A - Acti 9 iC60H Type C 440 V, 12 → 133 V, 220 → 240 V, 380 → 415 V 100 → 133V 10 kA DIN Rail 85mm 36mm 78.5mm -
RS Stock No. 849-6585
Mfr. Part No.EUC3P16C
BrandEuropa
€21.67
Each
units
3 16 A - EU EUC Type C 230/400 V - 10 kA - 54mm 78mm 87mm -
RS Stock No. 383-1958
Mfr. Part No.5SY4106-6
BrandSiemens
€20.58
Each
units
1 6 A - Sentron 5SY4 Type B 400 V - 10 kA - 89.8mm 17.6mm 76.4mm -
RS Stock No. 486-861
Mfr. Part No.PXL-C5/1
BrandEaton
€21.46
Each
units
1 5 A - xPole PXL, S200 Type C 400 V 48V 10 kA - 17.5mm 80mm 60mm -
RS Stock No. 791-3477
Mfr. Part No.A9F55120
€16.90
Each
units
1 20 A - Acti 9 iC60H Type D 100 → 133 V, 12 → 60 V, 220 → 240 V 72 V, 12 → 48 V 10 kA DIN Rail 85mm 18mm 78.5mm -
RS Stock No. 734-9618
Mfr. Part No.A9N21067
€111.78
Each
units
3 + N, 3+N 25 A - Acti 9 DT40 Type C 400 V - 6 kA - - - - -
New
RS Stock No. 842-0718
Mfr. Part No.NRAS1100-30A-AA
BrandIdec
€14.20
Each
units
- - - - - - - - - - - - - -
RS Stock No. 125-1466
Mfr. Part No.1492-SPM1C630
€43.30
Each
units
1 63 A - 1492 1492SPM Type C 277 V 48V 10 kA - 17.5mm 74mm 88mm General Purpose
RS Stock No. 825-5548
Mfr. Part No.P1MB1PB02
BrandLovato
€21.85
Each
units
1 2 A - ModuLo P1MB Type B 230 V 60V 10 kA - 86.5mm 18mm 79.52mm -
RS Stock No. 814-7677
Mfr. Part No.MG24445
€134.86
Each
units
2 4 A - - C60 Type C 277 V, 480 V 125V 10 kA, 20 kA - 12.86mm 8.27mm 73mm -
Related Products
A range of MCB automatic cut-outs in B, ...
Description:
A range of MCB automatic cut-outs in B, C and D characteristics To secure light, socket outlet and control current circuits The continuous current corresponds to the nominal current strength of fuse links These can be replaced by B automatic ...
Acti 9 Schneider iC60L series multi-standard circuit breakers ...
Description:
Acti 9 Schneider iC60L series multi-standard circuit breakers combine circuit protection against short circuit currents and circuit protection against overload currents it also protects people against indirect contact with TN and IT neutral systems Fully compliant with standards IEC/EN 60898 ...
Miniature Circuit Breakers; Contact Position indicated by switch ...
Description:
Miniature Circuit Breakers; Contact Position indicated by switch levers B, C and D curve Visisafe green strip indicates and guarantees the safe position of contacts VisiTrip red window on the front face indicates fault tripping allowing fast diagnosis, resolution, and ...
Reflex iC60 is integrated control circuit breaker which ...
Description:
Reflex iC60 is integrated control circuit breaker which combines circuit protection against short-circuit currents and circuit protection against overload currents, it easily communicates with PLCs without the need for add-ons or retrofitsIt is especially dedicated to the load remote management ...