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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รายละเอียดสินค้า / Description ราคา / Price Number of Poles Current Rating Model Number Range Series Rated AC Voltage Tripping Characteristics Mounting Style Rated DC Voltage Breaking Capacity at Maximum Voltage Rating Length Width Depth Break Time
RS Stock No. 776-8863
หมายเลขชิ้นส่วนของผู้ผลิต / Mfr. Part No.A9K24325
THB1,149.50
Each
Units
3 25 A - Acti 9 iK60N 400V Type C - - 6000 A - 54mm - -
RS Stock No. 539-8201
หมายเลขชิ้นส่วนของผู้ผลิต / Mfr. Part No.2CDS211001R0064 SH201-C6
Brand :ABB
THB519.26
Each
Units
1 6 A - System M Pro S200 440V Type C - 60V 6 kA 85mm 17.5mm 69mm -
RS Stock No. 772-1530
หมายเลขชิ้นส่วนของผู้ผลิต / Mfr. Part No.A9N61531
THB4,559.66
Each
Units
2 16 A - Acti 9 C60H-DC - Type C - 500V - - 36mm 73mm -
RS Stock No. 489-6625
หมายเลขชิ้นส่วนของผู้ผลิต / Mfr. Part No.5SY6106-7
Brand :Siemens
THB1,176.80
Each
Units
1 6 A - Sentron 5SY6 230 V, 400V Type C - - 6 kA 89.8mm 17.6mm 76.4mm -
RS Stock No. 864-4352
หมายเลขชิ้นส่วนของผู้ผลิต / Mfr. Part No.242405 & PLSM-C16/2-MW
THB1,923.96
Each
Units
2 16 A - XPole PLSM - Type C - 48V 10 kA 35mm 80mm 75mm -
RS Stock No. 124-3156
หมายเลขชิ้นส่วนของผู้ผลิต / Mfr. Part No.5SY4150-7
Brand :Siemens
THB2,101.75
Each
Units
1 50 A - Sentron 5SY4 230 V, 400V Type C - - 10 kA 17.6mm 76.4mm 89.8mm -
RS Stock No. 791-3199
หมายเลขชิ้นส่วนของผู้ผลิต / Mfr. Part No.A9F53210
THB3,119.92
Each
Units
2 10 A - Acti 9 iC60H 12 → 133 V, 220 → 240 V, 380 → 415V, 440 V Type B DIN Rail 100 → 133V 10 kA 85mm 36mm 78.5mm -
RS Stock No. 791-3332
หมายเลขชิ้นส่วนของผู้ผลิต / Mfr. Part No.A9F54206
THB3,574.58
Each
Units
2 6 A - Acti 9 iC60H 12 → 133 V, 220 → 240 V, 380 → 415V, 440 V Type C DIN Rail 100 → 133V 10 kA 85mm 36mm 78.5mm -
RS Stock No. 622-0036
หมายเลขชิ้นส่วนของผู้ผลิต / Mfr. Part No.5SY4104-7
Brand :Siemens
THB1,207.20
Each
Units
1 4 A - Sentron 5SY4 230 V, 400V Type C - - 10 kA 89.8mm 17.6mm 76.4mm -
RS Stock No. 864-4403
หมายเลขชิ้นส่วนของผู้ผลิต / Mfr. Part No.242478 & PLSM-C40/3-MW
THB2,768.18
Each
Units
3 40 A - XPole PLSM - Type C - 48V 10 kA 52.5mm 80mm 75mm -
RS Stock No. 521-4951
หมายเลขชิ้นส่วนของผู้ผลิต / Mfr. Part No.5SY6104-7
Brand :Siemens
THB1,179.11
Each
Units
1 4 A - Sentron 5SY6 230 V, 400V Type C - - 6 kA 89.8mm 17.6mm 76.4mm -
RS Stock No. 776-3076
หมายเลขชิ้นส่วนของผู้ผลิต / Mfr. Part No.A9N18369
THB26,926.04
Each
Units
3 125 A - Acti 9 C120N 440V Type C - ≤375V 10 kA, 20 kA - - 81mm -
RS Stock No. 776-3064
หมายเลขชิ้นส่วนของผู้ผลิต / Mfr. Part No.A9N18365
THB15,888.96
Each
Units
3 80 A - Acti 9 C120N 440V Type C - ≤375V 10 kA, 20 kA 81mm 73mm 81mm -
RS Stock No. 776-3225
หมายเลขชิ้นส่วนของผู้ผลิต / Mfr. Part No.A9N61537
THB4,378.97
Each
Units
2 40 A - Acti 9 C60H-DC - Type C - 500V 20 kA - - 81mm -
RS Stock No. 734-9068
หมายเลขชิ้นส่วนของผู้ผลิต / Mfr. Part No.A9F77210
THB2,616.32
Each
Units
2 10 A - Acti 9 iC60N 12 → 60 V, 100 → 130 V, 220 → 240 V, 380 → 415V, 400 V, 440 V Type C - 12 → 144V 6 kA - 36mm - -
RS Stock No. 776-8829
หมายเลขชิ้นส่วนของผู้ผลิต / Mfr. Part No.A9F84316
THB1,688.96
Each
Units
3 16 A - Acti 9 iC60H 440V Type C - 144V 10 kA - 54mm - -
RS Stock No. 734-9239
หมายเลขชิ้นส่วนของผู้ผลิต / Mfr. Part No.A9F77206
THB2,908.07
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Units
2 6 A - Acti 9 iC60N 12 → 60 V, 100 → 130 V, 220 → 240 V, 380 → 415 V, 400 V, 440V Type C - 12 → 144V 6 kA - - - -
RS Stock No. 131-955
หมายเลขชิ้นส่วนของผู้ผลิต / Mfr. Part No.2CDS272001R0324 S202M-C32
Brand :ABB
THB2,009.55
Each
Units
2 32 A - System M Pro S200 440V Type C - 125V 10 kA 88mm 35mm 75.8mm -
RS Stock No. 489-6675
หมายเลขชิ้นส่วนของผู้ผลิต / Mfr. Part No.5SY6132-6
Brand :Siemens
THB624.55
Each
Units
1 32 A - Sentron 5SY6 230 V, 400V Type B - - 6 kA 89.8mm 17.6mm 76.4mm -
RS Stock No. 488-7457
หมายเลขชิ้นส่วนของผู้ผลิต / Mfr. Part No.2CDS251001R0065 - S201B6
Brand :ABB
THB611.13
Each
Units
1 6 A - System M Pro S200 253V Type B - 72V 6 kA 88mm 17.5mm 75.8mm -