KFM3X Series Molded Case Circuit Breaker

Overview & scope

The KFM3X series molded case circuit breakers are suitable for AC 50/60 Hz circuits with rated operational voltage 690 V and below and rated current up to 800 A, generally for power distribution. Breakers rated 630 A and below can also be used for motor protection.

Distribution breakers protect lines and power supply equipment against overload, short circuit and undervoltage. Motor-protection breakers handle starting and running breaking of squirrel-cage motors with characteristics meeting GB/T 14048.4. The full series provides reliable contact indication and isolation per GB 50054.

MCCB

Design & features

Four breaking-capacity types: C (economy), S (standard), M (higher), H (high).
C / S / M types may be connected with incoming line at the bottom for AC 400 V distribution systems.
Fast closing and fast breaking operating mechanism; parallel-conductor contact system with repulsion-assisted H-type contacts for rapid interruption.
Zero or short arcing distance; compact construction.
Dedicated PV grid-connection version with undervoltage release module and electric mechanism (control voltage AC 230 V / 400 V, 50 Hz).
Tropical damp (TH) version tested to GB/T 2423.4 and GB/T 2423.18.
Draw-out device available for 400 / 800 frames only.

Key technical data

Key technical data	Value	Source
Series / Type	KFM3X Series Molded Case Circuit Breaker	P6
Frame sizes	100 / 160 / 250 / 400 / 630 / 800	P8
Rated operational voltage Ue	AC690V and below	P7
Rated current In	Up to 800A; 630A and below for motor protection	P7
Standards	IEC 60947-1/-2/-4-1, GB/T 14048.1/.2/.4	P7
Ambient temperature	-40 °C to +70 °C (derate above +40 °C) (℃)	P7
Installation altitude	up to 2000 m (m)	P7
Pollution degree	Degree 3 (级 / degree)	P7
Installation direction	Vertical, inclination to vertical ≤ ±22.5°	P7
Tropical damp type (TH)	Complies with GB/T 2423.4 and GB/T 2423.18	P7

The full Icu / Ics / Icm matrix per voltage level is available from the original catalog and on request. Values below are summary figures verified against the catalog.

Product gallery

Outline & installation

Dimension drawings for this series are being prepared from the original artwork. Contact us to request them.

Frame / model list

KFM3X-100 KFM3X-160 KFM3X-250 KFM3X-400 KFM3X-630 KFM3X-800

Frame sizes	Note	Source
KFM3X-100	—	P7–P9
KFM3X-160	—	P7–P9
KFM3X-250	—	P7–P9
KFM3X-400	Draw-out device available	P7–P9
KFM3X-630	—	P7–P9
KFM3X-800	Draw-out device available	P7–P9

Accessories

Undervoltage release (incl. PV module)

Includes the PV grid-connection module: undervoltage trip 70%–20% Un, loss-of-voltage trip below 20% Un, overvoltage protection above 135% Un, trip delay adjustable 0–10 s.

Source: P21 / P45 / P67

Shunt release

DC24V / DC110V / DC220V; reliable trip between 70%–110% rated control voltage; 50 cm lead as standard, 100/150 cm optional.

Source: P8 / P38 等

Auxiliary & alarm contacts

Up to 10 NO + 10 NC independent contacts on KFW3; three-position and ready-to-close contacts optional.

Source: P14–P17

Electric operating mechanism

New-generation DC3 mechanism; enables automatic closing with voltage check in PV grid-connection schemes.

Source: P23 / P47 / P69

Communication module

Status upload for thermo-magnetic breakers once the module is fitted.

Source: P25 / P73

Draw-out device

Available for 400 / 800 frames only. KFW3 offers a draw-out version natively (connected / test / disconnected).

Source: P24 / P48 / P71

Accessories →

Ordering information

Ordering codes are listed in the catalog (P38). Specify frame size, breaking type (C/S/M/H), poles, rated current, accessory codes and installation/wiring method.