5sj43 Siemens Miniature Circuit Breaker

5sj43 Siemens Miniature Circuit Breaker is suitable for Reverse Feed Connections, miniature circuit breakers IEC feature touch protection to EN 50274, visible indicator for ON and OFF/trip, and DIN rail mounting (35 mm). Smaller Size than traditional MCCBs, breakers include providing identical wire screw connections on line and load sides. The product line is available with a range of busbar & busbar accessories (UL recognized to file E321559).

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  • Tripping Characteristic
    The expected tripping behavior, and in particular the expected break time of the desired MCB can be determined from its I-t tripping characteristic.
  • In line with the two existing tripping systems (overload release with bimetal, short circuit release with magnet coil), the path of the I-t tripping characteristic consists of two characteristic curve sections:
    • Overload section (thermal)
    • Short circuit release section (magnetic)
  • The overload section of the curve describes the tripping behavior of the bimetal, while the short circuit release section of the characteristic curve describes the release behavior of the short circuit coil.
  • Depending on the equipment used and the operational behavior of the connected loads the short
    circuit release of the MCB must trip to ensure safe and efficient short circuit protection. These are called the tripping characteristics. The following tripping characteristics for MCBs are standardized in accordance with IS/IEC 60898-1
    • Tripping Characteristic B: 3-5 x In
    • Tripping Characteristic C: 5-10 x In
  • ‘B’ Characteristic MCBs reacts quickly to short circuit, and are set to trip when the current passing through them is between 3 to 5 times of the normal full load current. They are suitable for protecting incandescent lighting and socket outlet circuits in domestic and commercial environments, where there is little risk of surges that could cause the MCB to trip.


Standards IS / IEC 60898-1 : 2015
Tripping characteristic B / C
Rated voltage Un V AC 240 / 415
Current Rating A 6 – 63
Operational voltage V AC





264 / 456

Rated breaking capacity Icn kA 4.5;6
Insulation coordination

•        Rated insulation voltage

•        Degree of pollution for overvoltage





250 / 440

2 / III

Handle end position, sealable Yes
Degree of protection IP20
CFC and silicone-free Yes
Conductor cross-sections mm2

•         Solid and standed

•         Finely stranded,

with end sleeve


0.75 … 25

0.75 … 25


•        Terminal tightening torque




2.5 … 3

Line load reversibility Any
Service life on average, with rated load 20 000 actuations
Ambient temperature °C -25 … +55, max. 95 % humidity,

storage temperature: -40 … +75