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NFIB

Product catalog summary

Overview: The document provides technical specifications and details for ISKRA NFIB Type B Residual Current Circuit Breakers (RCCBs). These breakers are designed to trip for type A conditions and additionally for smooth direct current (d.c.) residual currents, which may arise from rectifying circuits and high-frequency alternating current (a.c.) residual currents. They are suitable for applications involving frequency inverters, medical devices, UPS, mobile installations, and elevators.

Specifications:

Not intended for use in d.c. systems or networks with frequencies other than 50 or 60 Hz.
Tripping conditions defined for frequencies up to 1 kHz.
Detection and interruption functions for type A residual currents are independent of line voltage; however, smooth d.c. residual currents require a supply voltage greater than 50 V.
Available versions include NFIBK (short-time delay tripping) and NFIBS (selective type).
Surge current withstand capability is 3 kA with an 8/20 µs waveform.
Degree of protection is IP20, which increases to IP40 when installed in a distribution box.
Assembly is compatible with a 35 mm wide mounting rail as per EN 60715.

Types and Features:

Type AC and A: Instantaneous tripping for sinusoidal alternating currents and pulsating direct currents.
Type S: Delayed break for selectivity, high resistance to surge currents, rated currents from 25 to 100 A, and residual currents of 100, 300, and 500 mA.
Type G: Short-time delayed breaking, resistant to unwanted tripping, rated currents from 25 to 100 A, and residual currents of 30, 100, 300, and 500 mA.
All types are VDE approved.

Technical Data:

Standards: IEC/EN 61008, IEC/EN 62423.
Number of poles: 2 or 4.
Rated voltage: 230 V for 2 poles, 400 V for 4 poles.
Rated impulse voltage: 4 kV.
Rated frequency: 50 Hz (60 Hz available on request).
Rated current: 25, 40, 63, 80 A.
Rated residual operating current: NFIBK (30, 100, 300, 500 mA), NFIBS (100, 300, 500 mA).
Frequency response range: 0 - 1000 Hz.
Rated making and breaking capacity: 800 A.
Max. back-up fuse for short-circuit current: 10 kA.
Terminal capacity: 1 ... 35 mm².
Ambient temperature range: -25 to +55°C (80 A to +40°C).
Storage temperature range: -30 to +60°C.
Tightening torque: 2.0 Nm.

Installation and Ordering:

Mains connection can be either top or bottom.
Ordering data includes rated residual operating current and rated current for specific types (e.g., NFI2BK, NFI4BS).

Catalog excerpts

Features • ISKRA NFIB are type B residual current circuit breakers (RCCB) for which tripping is ensured as for type A and in addition for smooth d.c. residual currents, residual d.c. currents which may result from rectifying circuits and high frequency a.c. residual currents. • Intended for use in applications with frequency inverters, medical devices, UPS, mobile installations, elevators... • The type B residual current circuit breakers are not intended for use in d.c. systems and networks with operating frequencies other than 50 or 60 Hz. • For type B tripping conditions for frequencies up...

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Note: Rated frequency 60 Hz on request. Ordering data Rated residual operating current IDn (A) Rated current In (A) Type

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Residual Current Circuit Breakers Type B - NFIB Dimensional drawings • Published by Iskra, d. d. • Version 2.0 November 2015

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