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

...
อ่านเพิ่มเติม อ่านน้อยกว่า

คัดกรอง / Filters

กำลังดูสินค้า 1 - 20 รายการจาก 550 รายการ / Viewing 1 - 20 of 550 products
ผลการค้นหาต่อหน้า / Results Per Page
รายละเอียดสินค้า / Description ราคา / Price Number of Poles Current Rating Model Number Range Series Rated AC Voltage Tripping Characteristics Breaking Capacity Mounting Style Rated DC Voltage Length Width Depth Application
RS Stock No. 776-8968
หมายเลขชิ้นส่วนของผู้ผลิต / Mfr. Part No.A9F74106
THB232.96
Each
Units
1 6 A - Acti 9 iC60N 230 V, 400 V Type C 6 kA - 72V - 18mm - -
RS Stock No. 776-3373
หมายเลขชิ้นส่วนของผู้ผลิต / Mfr. Part No.A9F73202
THB4,027.25
Each
Units
2 2 A - Acti 9 iC60N 440 V Type B 6 kA - 125V 36mm - 85mm -
RS Stock No. 734-9141
หมายเลขชิ้นส่วนของผู้ผลิต / Mfr. Part No.A9F77310
THB3,975.98
Each
Units
3 10 A - Acti 9 iC60N 100 → 130 V, 12 → 60 V, 220 → 240 V, 380 → 415 V, 400 V, 440 V Type C 6 kA - 12 → 144V - - - -
RS Stock No. 776-8845
หมายเลขชิ้นส่วนของผู้ผลิต / Mfr. Part No.A9F84440
THB4,193.28
Each
Units
4 40 A - Acti 9 iC60H 440 V Type C 10 kA - 250V - 72mm - -
RS Stock No. 776-3436
หมายเลขชิ้นส่วนของผู้ผลิต / Mfr. Part No.A9F74102
THB1,836.82
Each
Units
1 2 A - Acti 9 iC60N 240 V Type C 10 kA - 72V 18mm 78.5mm 85mm -
RS Stock No. 772-1515
หมายเลขชิ้นส่วนของผู้ผลิต / Mfr. Part No.A9N61526
THB5,101.37
Each
Units
2 6 A - Acti 9 C60H-DC - Type C - - 500V - 36mm 73mm -
RS Stock No. 776-3449
หมายเลขชิ้นส่วนของผู้ผลิต / Mfr. Part No.A9F74104
THB1,806.93
Each
Units
1 4 A - Acti 9 iC60N 240 V Type C 10 kA - 72V 18mm - 85mm -
RS Stock No. 791-3467
หมายเลขชิ้นส่วนของผู้ผลิต / Mfr. Part No.A9F55104
THB1,020.63
Each
Units
1 4 A - Acti 9 iC60H 100 → 133 V, 12 → 60 V, 220 → 240 V Type D 10 kA DIN Rail 72 V, 12 → 48 V 85mm 18mm 78.5mm -
RS Stock No. 776-8860
หมายเลขชิ้นส่วนของผู้ผลิต / Mfr. Part No.A9K24320
THB1,149.50
Each
Units
3 20 A - Acti 9 iK60N 400 V Type C 6000 A - - - 54mm - -
RS Stock No. 772-1530
หมายเลขชิ้นส่วนของผู้ผลิต / Mfr. Part No.A9N61531
THB5,380.63
Each
Units
2 16 A - Acti 9 C60H-DC - Type C - - 500V - 36mm 73mm -
RS Stock No. 776-8863
หมายเลขชิ้นส่วนของผู้ผลิต / Mfr. Part No.A9K24325
THB1,149.50
Each
Units
3 25 A - Acti 9 iK60N 400 V Type C 6000 A - - - 54mm - -
RS Stock No. 776-3076
หมายเลขชิ้นส่วนของผู้ผลิต / Mfr. Part No.A9N18369
THB20,650.81
Each
Units
3 125 A - Acti 9 C120N 440 V Type C 10 kA, 20 kA - ≤375V - - 81mm -
RS Stock No. 776-3225
หมายเลขชิ้นส่วนของผู้ผลิต / Mfr. Part No.A9N61537
THB5,241.57
Each
Units
2 40 A - Acti 9 C60H-DC - Type C 20 kA - 500V - - 81mm -
RS Stock No. 791-3332
หมายเลขชิ้นส่วนของผู้ผลิต / Mfr. Part No.A9F54206
THB2,466.50
Each
Units
2 6 A - Acti 9 iC60H 440 V, 12 → 133 V, 220 → 240 V, 380 → 415 V Type C 10 kA DIN Rail 100 → 133V 85mm 36mm 78.5mm -
RS Stock No. 776-3064
หมายเลขชิ้นส่วนของผู้ผลิต / Mfr. Part No.A9N18365
THB14,930.87
Each
Units
3 80 A - Acti 9 C120N 440 V Type C 10 kA, 20 kA - ≤375V 81mm 73mm 81mm -
RS Stock No. 791-3199
หมายเลขชิ้นส่วนของผู้ผลิต / Mfr. Part No.A9F53210
THB2,164.17
Each
Units
2 10 A - Acti 9 iC60H 440 V, 12 → 133 V, 220 → 240 V, 380 → 415 V Type B 10 kA DIN Rail 100 → 133V 85mm 36mm 78.5mm -
RS Stock No. 776-8974
หมายเลขชิ้นส่วนของผู้ผลิต / Mfr. Part No.A9F74120
THB186.37
Each
Units
1 20 A - Acti 9 iC60N 230 V, 400 V Type C 6 kA - 72V - 18mm - -
RS Stock No. 818-8571
หมายเลขชิ้นส่วนของผู้ผลิต / Mfr. Part No.MG24114
THB3,156.52
Each
Units
1 6 A - Acti 9 C60 277 V Type B 5 kA - - 18mm 81mm 78.5mm -
RS Stock No. 734-9068
หมายเลขชิ้นส่วนของผู้ผลิต / Mfr. Part No.A9F77210
THB2,430.26
Each
Units
2 10 A - Acti 9 iC60N 400 V, 440 V, 100 → 130 V, 12 → 60 V, 220 → 240 V, 380 → 415 V Type C 6 kA - 12 → 144V - 36mm - -
RS Stock No. 734-9239
หมายเลขชิ้นส่วนของผู้ผลิต / Mfr. Part No.A9F77206
THB2,958.29
Each
Units
2 6 A - Acti 9 iC60N 100 → 130 V, 12 → 60 V, 220 → 240 V, 380 → 415 V, 400 V, 440 V Type C 6 kA - 12 → 144V - - - -