Sigma F+E 3 2.0

Clear fault type indication

Sigma F+E 3 2.0 is a combined short-circuit and earth fault indicator. Due to the measuring principle the earth fault indication is suitable for low-impedance, solidly and isolated earthed neutral networks.

The current is measured via three single-phase current sensors. This allows phase-selective fault detection and indication.

There are two response criteria for short-circuit detection, fixed response values with response delay or auto-adjustment based on load current.

If the current for the selected response criterion – fixed value or self-adjustment – is exceeded, the fault-affected phase will be indicated by a bright flashing LED and remote contact will be activated. A double  flashing LED signals a second fault that has occurred within the reset time, e. g. by an automatic reclose attempt and the remote contact will be reactivated.

Two additional LEDs display the fault type. The red LED I>> signals a short-circuit, the yellow LED IE> signals an earth fault. The L1, L2 and L3 indication fields display the fault-affected phase. In addition, phase-selective (L1, L2, L3) or group-selective (I>>, IE>, I>> and IE>) remote signalling is possible.

For testing and commissioning purposes, the trip current values can be reduced to 10 A without changing the DIP switch settings.

Sigma F+E 3 2.0 AC/DC

This version can be connected to auxiliary supply. If the auxiliary power drops out in the event of a fault, the LED indicator can operate using a back-up capacitor for up to 8 hours.

Equipment set includes:

  • 1 display unit
  • 3 single-phase current sensors
  • Short-circuit and earth fault detection from 3 single-phase current sensors
  • Phase-selective fault indication
  • Trip current values: load-dependent self-adjustment or fixed values
  • Single and double flash mode for operation in radial and ring networks
  • With auxiliary supply and capacitor storage available in AC/DC version

Your advantages

  • No false trips due to harmonics
  • Highly visible LED fault indication
  • Detection of high-impedance earth faults
  • Clear fault type indication via LED
  • Retrofit ready for earth and short-circuit indicators with monitoring/control and fault direction function

Technical specifications

Earth fault detection methods

Earth short-circuit

Low-impedance/short-term low-impedance earthed ---
Isolated earthed ---
Resonant earthed -
Earth short-circuit trip current

20, 40, 60, 80, 100, 120 or 160 A

Response delay earth short-circuit

60, 80, 200, 300 ms

Trip current transient method -
Trip current active current cos ɸ -
Response delay active current cos ɸ -
Trip current reactive current sin ɸ -
Response delay reactive current sin ɸ -
Trip current permanent earth fault -
Response delay permanent earth fault -
Trip current pulse detection -
Short-circuit trip current

200, 300, 400, 600, 800, 1,000, 2,000 A, self-adjustment

Response delay short-circuit

40, 80, 200, 300 ms


Short-circuit: 3 red LEDs (L1, L2, L3), 1 red LED I>>; earth fault: 3 red LEDs (L1, L2, L3), 1 yellow LED IE>

Relay contacts 3
Remote contact

Potential-free permanent or momentary contact

Contact capacity: 230 V AC/1 A/62.5 VA max.

220 V DC/1 A/60 W max.

RS485/Modbus-RTU -
USB port -
Binary inputs -
Ethernet interface -
Manual reset ---
Remote reset ---
Automatic time reset ---
Reset via interface -
Reset on current restoration ---
Reset on voltage restoration -
Reset on restoration of auxiliary supply -
Reset via Explorer Software -
Internal power supply

Long-life lithium cell, active flashing time >900 h, shelf life ≥20 years

AC/DC version: back-up capacitor, max. 8 h

External auxiliary supply AC/DC version: 24 – 230 V AC/DC
CT powered ---

Polycarbonate, IP40

Temperature range -30 to +70 °C
Cable diameter -
  1. Highly visible, phase-selective LED fault indication
  2. Differentiation of short-circuit and earth fault
  3. Setting via DIP switch behind front panel
  4. Test/Reset button
  5. Three remote contacts
  6. Push‐in clamps for quick installation
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