Siemens SENTRON 4NC5923-5LT21 Through-hole Current Transformer 250/5 A, 5 VA, Class 1, 30x10 mm Busbar Opening

Electrical installers and panel builders use this Siemens SENTRON through-hole current transformer to measure AC currents up to 250 A in low-voltage distribution boards. The transformer converts the primary current into a standard 5 A secondary signal for connection to measuring instruments or energy meters.

Key specifications

• Primary rated current: 250 A
• Secondary rated current: 5 A
• Rated power: 5 VA
• Accuracy class: 1
• Busbar opening (W x H): 30 x 10 mm
• Max. cable diameter: 20 mm
• Frequency: 50/60 Hz
• Rated insulation voltage: 0.72 kV
• Rated impulse withstand voltage: 3 kV
• Rated short-time thermal current: 15 kA (1 s)
• Rated dynamic current: 37.5 kA
• Mounting: snap-on or screw
• Operating temperature: -5 to +50 °C

Why choose it

The transformer meets IEC 61869-2 and delivers reliable measurement with class 1 accuracy. Its compact design with snap-on mounting allows fast installation on busbars or cables without interrupting the circuit.

Ideal use cases

• Current monitoring in distribution panels
• Energy management systems
• Building automation
• Industrial control cabinets

Good to know

The transformer is part of the SENTRON series and is suitable for 50/60 Hz networks. It provides galvanic isolation between the primary circuit and the measuring circuit.