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

...
顯示內容 隱藏內容

篩選條件

正在檢視 1 - 20,共 4306 項產品
Results per page
Description 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庫存編號 791-3338
製造零件編號A9F54204
TWD4,243.00
單位
2 4 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庫存編號 791-3473
製造零件編號A9F55116
TWD725.00
單位
1 16 A - Acti 9 iC60H 12 → 60 V, 100 → 133 V, 220 → 240V Type D DIN Rail 12 → 48V, 72 V 10 kA 85mm 18mm 78.5mm -
RS庫存編號 772-1296
製造零件編號5SY4206-7
BrandSiemens
TWD2,512.00
單位
2 6 A - Sentron 5SY4 400V Type C - - 10 kA 90mm 36mm 76mm -
RS庫存編號 776-3216
製造零件編號A9N61534
TWD5,244.00
單位
2 30 A - Acti 9 C60H-DC - Type C - 500V 20 kA 36mm 73mm 81mm -
RS庫存編號 622-0014
製造零件編號5SY4102-7
BrandSiemens
TWD959.00
單位
1 2 A - Sentron 5SY4 230 V, 400V Type C - - 10 kA 89.8mm 17.6mm 76.4mm -
RS庫存編號 772-1319
製造零件編號5SY4216-7
BrandSiemens
TWD2,720.00
單位
2 16 A - Sentron 5SY4 400V Type C - - 10 kA 90mm 36mm 76mm -
RS庫存編號 131-955
製造零件編號2CDS272001R0324 S202M-C32
BrandABB
TWD2,009.00
單位
2 32 A - System M Pro S200 440V Type C - 125V 10 kA 88mm 35mm 75.8mm -
RS庫存編號 521-4951
製造零件編號5SY6104-7
BrandSiemens
TWD1,097.00
單位
1 4 A - Sentron 5SY6 230 V, 400V Type C - - 6 kA 89.8mm 17.6mm 76.4mm -
RS庫存編號 124-3156
製造零件編號5SY4150-7
BrandSiemens
TWD1,961.00
單位
1 50 A - Sentron 5SY4 230 V, 400V Type C - - 10 kA 17.6mm 76.4mm 89.8mm -
RS庫存編號 383-2024
製造零件編號5SY4110-7
BrandSiemens
TWD1,093.00
單位
1 10 A - Sentron 5SY4 400V Type C - - 10 kA 89.8mm 17.6mm 76.4mm -
RS庫存編號 776-3253
製造零件編號A9F87232
TWD4,774.00
單位
2 32 A - Acti 9 iC60H 440V Type C - 125V 10 kA - 78.5mm 85mm -
RS庫存編號 790-8863
製造零件編號A9F44132
TWD895.00
單位
1 32 A - Acti 9 iC60N 12 → 60 V, 100 → 133 V, 220 → 240V Type C - 12 → 48 V, 72V 6 kA 18mm 85mm 78.5mm -
RS庫存編號 776-3449
製造零件編號A9F74104
TWD2,360.00
單位
1 4 A - Acti 9 iC60N 240V Type C - 72V 10 kA 18mm - 85mm -
RS庫存編號 790-7361
製造零件編號A9C65340
TWD14,242.00
單位
3 40 A - Acti 9 iC60H 220 → 240 V, 380 → 415V Type C - 24V 10 kA - 84mm 77mm -
RS庫存編號 746-7986
製造零件編號2CDS252001R0377 S202-K6
BrandABB
TWD2,598.00
單位
2 6 A - System M Pro S200 400V Type K - - 6 kA 88mm 35mm 69mm -
RS庫存編號 772-1372
製造零件編號5SY4310-7
BrandSiemens
TWD3,815.00
單位
3 10 A - Sentron 5SY4 400V Type C - - 10 kA 89.8mm 52.8mm 76mm -
RS庫存編號 624-0399
製造零件編號278876 & FAZ-C32/3
BrandEaton
TWD2,694.00
單位
3 32 A - XEffect FAZ 400V Type C - - 10 kA 80mm 52.5mm 73.5mm -
RS庫存編號 772-1280
製造零件編號5SY4204-7
BrandSiemens
TWD3,180.00
單位
2 4 A - Sentron 5SY4 400V Type C - - 10 kA 90mm 36mm 76mm -
RS庫存編號 521-4939
製造零件編號5SY6102-7
BrandSiemens
TWD1,097.00
單位
1 2 A - Sentron 5SY6 230 V, 400V Type C - - 6 kA 89.8mm 17.6mm 76.4mm -
RS庫存編號 776-3433
製造零件編號A9F74101
TWD2,361.00
單位
1 1 A - Acti 9 iC60N 240V Type C - 72V 10 kA 18mm 78.5mm 85mm -