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 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
New
RS Stock No. 189-5640
Mfr. Part No.356181
BrandABB
PHP5,355.32
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1 3 A S201P-K3 - - 230 V Type K 25 kA DIN Rail Mount - 69mm 17.5mm 88mm Commercial, Industrial, Residential
New
RS Stock No. 189-5699
Mfr. Part No.352133
BrandABB
PHP2,275.22
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1 6 A S201-C6 - S 200 230 V, 400 V Type C 20 kA DIN Rail 72V 17.5mm 69mm 88mm Commercial, Industrial, Residential
New
RS Stock No. 189-5682
Mfr. Part No.352254
BrandABB
PHP6,484.11
Each
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2 2 A S202-D2 - S 200 230 V, 400 V Type D 20 kA DIN Rail 125V 35mm 69mm 88mm Commercial, Industrial, Residential
New
RS Stock No. 189-5646
Mfr. Part No.703005
BrandABB
PHP1,957.02
Each
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2 16 A E211-16-20 - - 250 / 415 V - - - - 93mm 9mm 85mm -
New
RS Stock No. 189-5695
Mfr. Part No.470238
BrandABB
PHP1,200.51
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1 + N 16 A SN201 L C16-L - SN201 230 V Type C 4.5 kA DIN Rail - 18mm 69mm 85mm Final Distribution and Protection of Long Cable Lenghts in TN and IT Systems
New
RS Stock No. 189-5701
Mfr. Part No.470229
BrandABB
PHP1,617.18
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1 + N 2 A SN201 L C2-L - SN201 230 V Type C 4.5 kA DIN Rail - 18mm 69mm 85mm Final Distribution and Protection of Long Cable Lenghts in TN and IT Systems
New
RS Stock No. 189-5684
Mfr. Part No.352258
BrandABB
PHP6,484.11
Each
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2 6 A S202-D6 - S 200 230 V, 400 V Type D 20 kA DIN Rail 125V 35mm 69mm 88mm Commercial, Industrial, Residential
New
RS Stock No. 189-5642
Mfr. Part No.442051
BrandABB
PHP11,131.31
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4 40 A F204 - - 230 / 400 V - - - - 60mm 70mm 80mm -
New
RS Stock No. 189-5697
Mfr. Part No.444051
BrandABB
PHP6,360.02
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2 40 A FH202 S AC-40/0,03 - FH 200 - Type AC - DIN Rail - 35mm 69mm 85mm Domestic Application
New
RS Stock No. 189-5703
Mfr. Part No.352140
BrandABB
PHP2,001.98
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1 25 A S201-C25 - S 200 230 V, 400 V Type C 20 kA DIN Rail 72V 17.5mm 69mm 88mm Commercial, Industrial, Residential
New
RS Stock No. 189-5639
Mfr. Part No.356183
BrandABB
PHP4,676.23
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1 6 A S201P-K6 - - 230 V Type K 25 kA DIN Rail Mount - 69mm 17.5mm 88mm Commercial, Industrial, Residential
New
RS Stock No. 189-5638
Mfr. Part No.472156
BrandABB
PHP17,720.15
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2 32 A DS202C - - 230 → 240 V Type C - - - 60mm 30mm 80mm -
New
RS Stock No. 189-5647
Mfr. Part No.471012
BrandABB
PHP10,075.95
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1 10 A DS201 - - 230 → 240 V Type C - - - 60mm 30mm 80mm -
New
RS Stock No. 189-5691
Mfr. Part No.362004
BrandABB
PHP2,330.43
Each
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2 40 A SD202/40 - SD 200 462 V - - DIN Rail 131V 35mm 69mm 88mm -
New
RS Stock No. 189-5693
Mfr. Part No.470227
BrandABB
PHP2,063.46
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1 + N 1 A SN201 L C1-L - SN201 230 V Type C 4.5 kA DIN Rail - 18mm 69mm 85mm Final Distribution and Protection of Long Cable Lenghts in TN and IT Systems