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. 847-3487
หมายเลขชิ้นส่วนของผู้ผลิต / Mfr. Part No.102187 & FAZ-D10/2-NA
Brand :Eaton
THB3,220.69
Each
Units
2 10 A - XEffect FAZ 240 → 415V Type D - - 10 kA 35.4mm 105mm 75.5mm -
RS Stock No. 776-3171
หมายเลขชิ้นส่วนของผู้ผลิต / Mfr. Part No.A9N61513
THB2,111.84
Each
Units
1 25 A - Acti 9 C60H-DC - Type C - 250V 20 kA 18mm - 81mm -
RS Stock No. 489-6596
หมายเลขชิ้นส่วนของผู้ผลิต / Mfr. Part No.5SY6116-7
Brand :Siemens
THB965.91
Each
Units
1 16 A - Sentron 5SY6 230 V, 400V Type C - - 6 kA 89.8mm 17.6mm 76.4mm -
RS Stock No. 791-3152
หมายเลขชิ้นส่วนของผู้ผลิต / Mfr. Part No.A9F53106
THB1,162.86
Each
Units
1 6 A - Acti 9 iC60H 12 → 60 V, 100 → 133 V, 220 → 240V Type B DIN Rail 12 → 48V, 72 V 10 kA 85mm 18mm 78.5mm -
RS Stock No. 624-0434
หมายเลขชิ้นส่วนของผู้ผลิต / Mfr. Part No.278873 & FAZ-C16/3
Brand :Eaton
THB3,428.79
Each
Units
3 16 A - XEffect FAZ 400V Type C - - 10 kA 80mm 52.5mm 73.5mm -
RS Stock No. 772-1521
หมายเลขชิ้นส่วนของผู้ผลิต / Mfr. Part No.A9N61528
THB4,589.13
Each
Units
2 10 A - Acti 9 C60H-DC - Type C - 500V - - 36mm 73mm -
RS Stock No. 132-122
หมายเลขชิ้นส่วนของผู้ผลิต / Mfr. Part No.2CDS272001R0164 S202M-C16
Brand :ABB
THB1,905.41
Each
Units
2 16 A - System M Pro S200 440V Type C - 125V 10 kA 88mm 35mm 75.8mm -
RS Stock No. 622-0008
หมายเลขชิ้นส่วนของผู้ผลิต / Mfr. Part No.5SY4101-7
Brand :Siemens
THB1,209.57
Each
Units
1 1 A - Sentron 5SY4 230 V, 400V Type C - - 10 kA 89.8mm 17.6mm 76.4mm -
RS Stock No. 772-1518
หมายเลขชิ้นส่วนของผู้ผลิต / Mfr. Part No.A9N61511
THB2,111.84
Each
Units
1 16 A - Acti 9 C60H-DC - Type C - 250V - 81mm - 73mm -
RS Stock No. 539-8223
หมายเลขชิ้นส่วนของผู้ผลิต / Mfr. Part No.2CDS211001R0164 SH201-C16
Brand :ABB
THB491.34
Each
Units
1 16 A - System M Pro S200 440V Type C - 60V 6 kA 85mm 17.5mm 69mm -
RS Stock No. 776-9034
หมายเลขชิ้นส่วนของผู้ผลิต / Mfr. Part No.A9F74320
THB1,630.72
Each
Units
3 20 A - Acti 9 iC60N 440V Type C - 144V 6 kA - 54mm - -
RS Stock No. 776-3382
หมายเลขชิ้นส่วนของผู้ผลิต / Mfr. Part No.A9F73204
THB3,234.44
Each
Units
2 4 A - Acti 9 iC60N 440V Type B - 125V 6 kA - - 85mm -
RS Stock No. 489-6530
หมายเลขชิ้นส่วนของผู้ผลิต / Mfr. Part No.5SY6106-6
Brand :Siemens
THB622.19
Each
Units
1 6 A - Sentron 5SY6 230 V, 400V Type B - - 6 kA 89.8mm 17.6mm 76.4mm -
RS Stock No. 776-3433
หมายเลขชิ้นส่วนของผู้ผลิต / Mfr. Part No.A9F74101
THB1,703.26
Each
Units
1 1 A - Acti 9 iC60N 240V Type C - 72V 10 kA 18mm 78.5mm 85mm -
RS Stock No. 535-4318
หมายเลขชิ้นส่วนของผู้ผลิต / Mfr. Part No.2CDS273001R0324 S203M-C32
Brand :ABB
THB2,536.61
Each
Units
3 32 A - System M Pro S200 440V Type C - - 10 kA - - 75.8mm -
RS Stock No. 734-9295
หมายเลขชิ้นส่วนของผู้ผลิต / Mfr. Part No.A9F87216
THB4,537.97
Each
Units
2 16 A - Acti 9 iC60H 12 → 60 V, 100 → 130 V, 220 → 240 V, 380 → 415 V, 400 V, 440V Type C - 12 → 144V 10 kA - - - -
RS Stock No. 791-3192
หมายเลขชิ้นส่วนของผู้ผลิต / Mfr. Part No.A9F53216
THB3,298.59
Each
Units
2 16 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. 847-3245
หมายเลขชิ้นส่วนของผู้ผลิต / Mfr. Part No.102167 & FAZ-C10/2-NA
Brand :Eaton
THB3,140.33
Each
Units
2 10 A - XEffect FAZ 240 → 415V Type C - - 10 kA 35.4mm 105mm 75.5mm -
RS Stock No. 435-370
หมายเลขชิ้นส่วนของผู้ผลิต / Mfr. Part No.2CCS893001R0825 S803N-B100
Brand :ABB
THB7,889.73
Each
Units
3 100 A - High Performance S800 400 V, 690V Type B - - 36 kA - 79.5mm 88.5mm -
RS Stock No. 791-3423
หมายเลขชิ้นส่วนของผู้ผลิต / Mfr. Part No.A9F54406
THB5,433.14
Each
Units
4 6 A - Acti 9 iC60H 12 → 133 V, 220 → 240 V, 380 → 415V, 440 V Type C DIN Rail 220 → 250V 10 kA 85mm 72mm 78.5mm -