The CW-421 is a measuring shunt for currents ± 30 A; it is designed for measurements in the automotive sector. The CW-421 is supplied with a rugged aluminium housing, which is equipped with a receptacle for blade-type fuses. The connection cable of the shunt is equipped with fuse contacts. That means the shunt can be inserted into the vehicle fuse box as a direct replacement for fuses. On the one hand, using the original fuses in the shunt means the circuit is protected by fuses specified for the vehicle in accordance with applicable regulations. And on the other, using the shunt directly in the circuit makes it possible to measure the current flowing in this circuit.

The measured value is issued by means of an analog output voltage from 0-10 VDC, which can, for example, be converted to a CAN signal by the CW-327 A/D converter from the CW-300 series. The accuracy of the shunt is 1%.

The small form factor and the range of the power supply from 9-15 VDC mean the CW-421 is extremely suitable to guarantee numerous current measurements in a vehicle fuse box. 


  • Measurement range: ± 30 A
  • Accuracy: 1% of measurement range
  • Temperature range: -40 °C to 85 °C
  • Rugged aluminium housing
  • Functions directly in the fuse box circuit 
  • Receptacle for original fuses on housing
  • Supports TEDS

Current measurement Channel

Number: 1
Measurement range: ± 30 A
Accuracy: 1 % of measurement range (at 25 °C)
Connector: Safety contacts for blade fuse socket, cable length 50 cm 

power supply

Supply voltage: 9 VDC to 15 VDC
Connector: Lemo FWG.1B.306 

Environmental conditions

Temperature range operation: -40 °C to 85 °C
Temperature range storage: -40 °C to +85 °C
Relative humidity: 35 % to 85 %, non-condensing

General information

Housing: Rugged aluminum case
Dimensions (LxWxH): 40 mm x 20 mm x 20 mm
Weigth: 65 g


Datasheet CW-421

Download (PDF)

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