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

...
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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. 259-8307
Mfr. Part No.7210.2000.0
BrandKopp
kr 128,89
Each
Units
2 10 A - - GREEN ELECTRIC Type B 230 → 400 V 60V 10 kA - - - - -
RS Stock No. 259-8313
Mfr. Part No.7216.2000.8
BrandKopp
kr 142,50
Each
Units
2 16 A - - GREEN ELECTRIC Type B 230 → 400 V 60V 10 kA - - - - -
RS Stock No. 239-5041
Mfr. Part No.7225.0000.2
BrandKopp
kr 51,91
Each
Units
1 25 A - - GREEN ELECTRIC Type B 230 → 400 V 60V 10 kA - - - - -
RS Stock No. 259-8436
Mfr. Part No.7225.3000.3
BrandKopp
kr 218,75
Each
Units
3 25 A - - GREEN ELECTRIC Type B 230 → 400 V 60V 10 kA - - - - -
RS Stock No. 239-5085
Mfr. Part No.7216.0100.5
BrandKopp
kr 83,58
Each
Units
1 16 A - - GREEN ELECTRIC Type C 230 → 400 V 60V 10 kA - - - - -
RS Stock No. 259-8616
Mfr. Part No.7225.3100.4
BrandKopp
kr 327,91
Each
Units
3 25 A - - GREEN ELECTRIC Type C 230 → 400 V 60V 10 kA - - - - -
RS Stock No. 259-8442
Mfr. Part No.7232.3000.5
BrandKopp
kr 298,09
Each
Units
1 32 A - - GREEN ELECTRIC Type B 230 → 400 V 60V 10 kA - - - - -
RS Stock No. 436-5733
Mfr. Part No.7216.0200.6
BrandKopp
kr 105,15
Each
Units
1 16 A - - GREEN ELECTRIC Type D 230 → 400 V 60V 10 kA - - - - -
RS Stock No. 259-8622
Mfr. Part No.7232.3100.6
BrandKopp
kr 372,18
Each
Units
3 32 A - - GREEN ELECTRIC Type C 230 → 400 V 60V 10 kA - - - - -
RS Stock No. 239-5091
Mfr. Part No.7220.0100.8
BrandKopp
kr 72,03
Each
Units
1 20 A - - GREEN ELECTRIC Type C 230 → 400 V 60V 10 kA - - - - -
RS Stock No. 436-5812
Mfr. Part No.7232.0200.6
BrandKopp
kr 141,57
Each
Units
1 32 A - - GREEN ELECTRIC Type D 230 → 400 V 60V 10 kA - - - - -
RS Stock No. 436-5783
Mfr. Part No.7216.3200.7
BrandKopp
kr 701,43
Each
Units
3 16 A - - GREEN ELECTRIC Type D 230 → 400 V 60V 10 kA - - - - -
RS Stock No. 259-8492
Mfr. Part No.7210.2100.1
BrandKopp
kr 193,90
Each
Units
2 10 A - - GREEN ELECTRIC Type C 230 → 400 V 60V 10 kA - - - - -
RS Stock No. 239-5063
Mfr. Part No.7206.0100.4
BrandKopp
kr 78,11
Each
Units
1 6 A - - GREEN ELECTRIC Type C 230 → 400 V 60V 10 kA - - - - -
RS Stock No. 259-8391
Mfr. Part No.7210.3000.7
BrandKopp
kr 192,23
Each
Units
3 10 A - - GREEN ELECTRIC Type B 230 → 400 V 60V 10 kA - - - - -
RS Stock No. 436-5676
Mfr. Part No.7210.0200.8
BrandKopp
kr 109,58
Each
Units
1 10 A - - GREEN ELECTRIC Type D 230 → 400 V 60V 10 kA - - - - -
RS Stock No. 259-8385
Mfr. Part No.7206.3000.4
BrandKopp
kr 220,83
Each
Units
3 6 A - - GREEN ELECTRIC Type B 230 → 400 V 60V 10 kA - - - - -
RS Stock No. 259-8565
Mfr. Part No.7206.3100.5
BrandKopp
kr 331,03
Each
Units
3 6 A - - GREEN ELECTRIC Type C 230 → 400 V 60V 10 kA - - - - -
RS Stock No. 259-8329
Mfr. Part No.7220.2000.1
BrandKopp
kr 134,45
Each
Units
2 20 A - - GREEN ELECTRIC Type B 230 → 400 V 60V 10 kA - - - - -
RS Stock No. 239-5079
Mfr. Part No.7210.0100.7
BrandKopp
kr 107,21
Each
Units
1 10 A - - GREEN ELECTRIC Type C 230 → 400 V 60V 10 kA - - - - -