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 Prix 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
N° de stock RS 731-9449
Référence fabricant4 067 71
MarqueLegrand
31,97 €
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1 + N 2 A - DX Range DNX3 Type C - - 4.5 kA - - - - -
N° de stock RS 734-9686
Référence fabricantA9F75332
118,73 €
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Unité
3 32 A - Acti 9 iC60N Type D 100 → 130 V, 12 → 60 V, 220 → 240 V, 380 → 415 V, 400 V, 440 V 12 → 144V 6 kA - - 54mm - -
N° de stock RS 746-7646
Référence fabricantS201-C1
MarqueABB
21,39 €
Each
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1 1 A - System M Pro S200 Type C 230 V - 6 kA - 88mm 17.5mm 69mm -
N° de stock RS 734-9658
Référence fabricantA9F75204
86,51 €
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2 4 A - Acti 9 iC60N Type D 400 V, 440 V, 100 → 130 V, 12 → 60 V, 220 → 240 V, 380 → 415 V 12 → 144V 6 kA - - - - -
N° de stock RS 776-6710
Référence fabricantA9N21595
106,05 €
Each
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3 + N 6 A - Acti 9 iDPN Type C 400 V - 10 kA - 54mm 70mm 80mm -
N° de stock RS 791-3408
Référence fabricantA9F54340
95,95 €
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3 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 54mm 78.5mm -
N° de stock RS 125-1468
Référence fabricant1492-SPM2C020
61,30 €
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2 2 A - 1492 1492SPM Type C 277 V, 480 V 96V 10 kA - 35mm 75mm 88mm General Purpose
N° de stock RS 527-9453
Référence fabricantS201-D6
MarqueABB
27,78 €
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1 6 A - System M Pro S200 Type D 253 V 72V 6 kA - - - 75.8mm -
N° de stock RS 734-9683
Référence fabricantA9F75316
108,14 €
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3 16 A - Acti 9 iC60N Type D 400 V, 440 V, 100 → 130 V, 12 → 60 V, 220 → 240 V, 380 → 415 V 12 → 144V 6 kA - - 54mm - -
N° de stock RS 734-9674
Référence fabricantA9F75310
108,50 €
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Unité
3 10 A - Acti 9 iC60N Type D 100 → 130 V, 12 → 60 V, 220 → 240 V, 380 → 415 V, 400 V, 440 V 12 → 144V 6 kA - - - - -
N° de stock RS 776-2676
Référence fabricantA9N21576
95,80 €
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3 10 A - Acti 9 iDPN Type C 400 V - 10 kA - 54mm - 80mm -
N° de stock RS 734-9677
Référence fabricantA9F75225
76,90 €
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2 25 A - Acti 9 iC60N Type D 100 → 130 V, 12 → 60 V, 220 → 240 V, 380 → 415 V, 400 V, 440 V 12 → 144V 6 kA - - 36mm - -
N° de stock RS 746-7576
Référence fabricantS202-B32
MarqueABB
50,47 €
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2 32 A - System M Pro S200 Type B 400 V - 6 kA - 88mm 35mm 69mm -
N° de stock RS 734-9655
Référence fabricantA9F75203
86,90 €
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2 3 A - Acti 9 iC60N Type D 100 → 130 V, 12 → 60 V, 220 → 240 V, 380 → 415 V, 400 V, 440 V 12 → 144V 6 kA - - - - -
N° de stock RS 622-0014
Référence fabricant5SY4102-7
MarqueSiemens
26,64 €
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1 2 A - Sentron 5SY4 Type C 230 V, 400 V - 10 kA - 89.8mm 17.6mm 76.4mm -
N° de stock RS 746-7699
Référence fabricantS202-C2
MarqueABB
58,52 €
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2 2 A - System M Pro S200 Type C 400 V - 6 kA - - 35mm 69mm -
N° de stock RS 825-5706
Référence fabricantP1MB2PC01
MarqueLovato
23,13 €
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2 1 A - ModuLo P1MB Type C 230 V, 400 V 80V 10 kA - 86.5mm 36mm 79.52mm -
N° de stock RS 847-3535
Référence fabricant102270 | FAZ-D16/3-NA
MarqueEaton
121,62 €
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Unité
3 16 A - xEffect FAZ Type D 240 → 415 V - 10 kA - 53.1mm 105mm 75.5mm -
N° de stock RS 776-2673
Référence fabricantA9N21577
88,50 €
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3 16 A - Acti 9 iDPN Type C 400 V - 10 kA - - - 80mm -
N° de stock RS 734-9248
Référence fabricantA9F74602
89,49 €
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1 + N 2 A - Acti 9 iC60N Type C 100 → 130 V, 12 → 60 V, 220 → 240 V, 230 V - 6 kA - - 36mm - -