C2544B250

What is this trip unit used for?

It is an electronic trip unit (MicroLogic Vigi 4.2 AB) designed to provide basic overload and short-circuit protection plus integrated earth-leakage (residual current) protection when fitted to compatible ComPacT NSX250 new generation circuit breakers.

Which circuit breaker range is it compatible with?

It is compatible with ComPacT new generation NSX250 circuit breakers.

What protection functions are included?

The protection functions are LSoIR: Long-time overload (L), short-time short-circuit with fixed delay (So), instantaneous short-circuit (I), and earth-leakage protection (R).

What is the rated current of the trip unit?

The trip unit rating is 250 A at 40°C (In). In practice, the long-time pick-up Ir is adjustable below this rating.

What is the adjustable range for long-time overload pick-up (Ir)?

Ir is adjustable from 140 A to 240 A.

Are the long-time delay settings adjustable?

No. The long-time delay (tr) is fixed, with characteristic points of 0.35 s at 7.2 × Ir, 0.5 s at 6 × Ir, and 15 s at 1.5 × Ir.

How is short-time short-circuit protection set?

The short-time pick-up (Isd) is adjustable from 1.5 to 10 × Ir. The short-time delay (tsd) is fixed.

What is the instantaneous short-circuit pick-up level?

Instantaneous protection pick-up (Ii) is fixed at 2880 A.

Does it include earth-leakage protection, and what class is it?

Yes. It has integrated earth-leakage protection, Class A.

What earth-leakage sensitivity settings are available?

The earth-leakage sensitivity (IΔn) is adjustable to 0.03 A, 0.1 A, 0.3 A, 0.5 A, 1 A, 3 A, or 5 A.

Can earth-leakage protection be turned off?

Yes. A specific OFF mode is available using the IΔn rotary switch.

What earth-leakage time delays can be selected?

The earth-leakage time delay (Δt) is adjustable to 0 ms, 60 ms, 150 ms, 500 ms, or 1 s.

How many poles does it support, and how is the neutral handled?

It is for 4-pole (4P) applications. Protected pole configurations include 3D + N/2, 4D, or 3D, with the neutral position specified as left. Neutral protection settings depend on configuration: 0.5 × Ir (3D + N/2), 1 × Ir (4D), or no protection (3D).

What is the rated operational voltage and network type?

Rated operational voltage (Ue) is 440 V AC at 50/60 Hz, for AC networks.

Does it support zone selective interlocking (ZSI)?

No. Zone selective interlocking is specified as without ZSI.

What local indication is provided on the trip unit?

Local signalling includes a flashing green LED for ready-to-operate, a red LED at 105% Ir for overload, an orange LED at 90% Ir for overload, and a yellow colour indicator for residual current.

What mounting arrangement is it intended for?

It is specified for fixed mounting mode on the circuit breaker.

What are the environmental operating and storage temperature ranges?

Operating ambient air temperature is -25°C to 70°C. Storage temperature is -40°C to 85°C.

What ingress protection (IP) rating does it have?

The trip unit is rated IP40 (per IEC 60529).

Which standards and insulation class are specified?

It conforms to EN/IEC 60947-2. Electrical shock protection class is Class II, and pollution degree is 3 (per IEC 60947-1).

Does it include thermal memory?

Yes. It includes thermal memory for 20 minutes before and after tripping.