On this page:

Electronic Circuit Breakers (ECBs)

A high switch-on capacity is combined with an electronic relay.
WAGO's space-saving ECBs come into play when the focus is on both safety and a superior price-performance ratio.

ECBs from the EPSITRON® family have a lot to offer:

  • They offer reliable protection against overload and short circuit.
  • They also enable activation of high-capacity loads of 50,000 microfarad and higher – without having to increase the nominal current setting.
  • One, two-, four- and eight-channel models with 0.5 to 12 A current ratings offer you the flexibility you need for setting the nominal current to suit your individual applications.
  • With a maximum width of 45 mm (1.772 inches), these ECBs feature high channel density to save space in the control cabinet.
  • Some devices are also available with active current limitation, preventing the power supply unit from overloading during a short circuit.


New Product

Single-Channel Electronic Circuit Breakers (ECBs)

The single-channel electronic circuit breakers provide reliable protection in a width of only 6 mm. Stefan Wagner presents the products in detail.

Protect Small Currents Easily

New WAGO 0.5 A Electronic Circuit Breaker

With WAGO’s single-channel electronic circuit breaker (787-2861/050-000), even small load currents of 0.5 A can now be easily protected in control circuits. Quick, reliable tripping after 4 ms is guaranteed with all seven available circuit breakers. In addition, the circuit breaker saves space in the control cabinet or system distribution box with its overall width of just 6 mm. Different control options for the integrated digital input allow channels to be set to a specific state, increasing usability. The digital output reports the current status. Since they have the same profile, direct commoning of the input and output voltages is possible across 857 and 2857 Series devices.

The Benefits for You:

  • Protection of load currents from 0.5 A to 8 A
  • Slim 6 mm (0.236 inch) housing saves space
  • Reliable tripping of the circuit breaker after just 4 ms

Discover More Electronic Circuit Breakers

Single-Channel ECBs

With a width of only 6 mm (0.236 inch), these new circuit breakers are the narrowest ECBs currently on the market. They are approximately 66% smaller than miniature circuit breakers to save even more space, particularly when used in control cabinets. These ECBs enable high-capacity loads greater than 50,000 microfarads to be switched on, without requiring further action or changing the nominal current, helping reduce false tripping due to inrush currents.

Your benefits:

  • 24 VDC / in six versions for rated currents of 1 to 8 A
  • With devices color coded according to nominal current
  • An extremely slimline version
  • Switch-on capacity: >50,000 µF
  • Wide operating temperature range: −25 … +70°C (−13 … +158°F)
  • Resetting, on/off switching directly on the module or remotely via digital input signal
  • Triggered signal output can also be combined as a group signal for up to 30 devices
  • Approvals: CE, UL 61010, UL 2367

2-, 4- and 8-Channel ECBs

WAGO's space-saving ECBs provide reliable protection with a superior price/performance ratio. They offer both outstanding features and reliable protection against overload and short circuits. With a maximum width of 45 mm (1.772 inches), these ECBs feature high channel density to save space in the control cabinet.

Your benefits:

  • Two-, four- and eight-channel protective switch with currents adjustable from 0.5 to 12 A
  • High switch-on capacity: >50,000 µF
  • Communication capability: remote monitoring and reset
  • Optional active current limitation
  • Approvals: CE, UL 60950, UL 2367, GL

The Benefits of WAGO’s ECBs for You

Compactness without Compromises

Width of just 6 mm (0.23 inch) maximizes panel space


Device identification via WMB Markers or TOPJOB® S Marking Strips


Intuitive status display

Each output channel has backlit buttons for operating status indication, on/off switching and acknowledgment

Trip Characteristics

Reliable, rapid, and precise disconnection in case of overcurrent or short circuit

Models Differentiated Visually

Devices color coded according to rated current

Simple Wiring

Bridgeable signal output and total reset for up to 30 devices


Many configuration options

Optional rated current setting from 1 to 8 A and seven different configuration options for the digital measurement output


Rotary switch

Rated current can be adjusted in six steps for each channel individually; transparent, sealable and markable cover



Fast and reliable communication via IO-Link protocol, signal contact, potential-free signal or Manchester protocol


Save Space in the Control Cabinet

Up to eight channels in just a 42 mm (1.653 inch) wide module

Why Secondary-Side Fuse Protection?

On the secondary side, switched-mode power supplies provide DC voltage to control circuit loads (e.g., controllers, operating panels, displays and auxiliary relays). These control circuits also call for wiring protection and if the load has no protective unit of its own, device protection as well. Furthermore, Machinery Directive EN 60204 requires the detection of hazardous ground faults in control circuits and switching off within five seconds.

The overcurrent protection in primary switched-mode power supplies reacts very quickly to overcurrents on the output side. Selective protection of individual current paths in the secondary circuit via fuses or conventional circuit breakers is often ineffective if the power supply cannot deliver a brief overcurrent.


What Types of Fuse Protection Are There?


Possible applications:

  • Low-voltage, high-power and DP fuses
  • High overcurrents required for fast tripping


  • In the example: ten-fold overcurrent (related to fuse nominal current): tripping within the range 30 ms (best case) or 200 ms (worst case)
  • Only two-fold overcurrent: tripping within the range 2 s (best case) or >100 s (worst case)

Thermal and Magnetic

Possible applications:

  • Found in circuit breakers or motor protection switches
  • High overcurrents required for fast tripping


  • In the example: three- to five-fold overcurrent for B-characteristic and AC operation, additional safety factor 1.2 or 1.5
  • Thus, in the worst case scenario, a tripping current of 7.5 times the nominal current is necessary.



Possible applications:

  • Ensure precision settings
  • Reaction within a short time – even at low overcurrents
  • Protection of long cable runs and small cross sections possible

ECBs ensure reliable protection, even at low overcurrents and with long cable lengths.


How Does an ECB Function?

The ECB verifies that the output current is greater than the nominal current. As soon as the output current exceeds the nominal current, the output is electronically switched off by a semiconductor switch. The trip time depends on the magnitude of the overcurrent. The measurement of the output current, processing and calculation of the tripping time, as well as actuation of the semiconductor switch are performed by a microprocessor that monitors one or more output channels. The corresponding tripping times can be taken from the graph on the right.


ECB Advantages:

  • Switch off secondary-side overcurrents and short circuits – even with long cable runs and small conductor cross-sections – precisely, quickly and repeatedly
  • Selectivity, especially with ECBs having active current limitation
  • Remote operation via digital input and output
  • Readout functions (communication) through serial data transfer via digital input and output
  • Advantageous installation size and width, for example, eight output channels in just 42 mm (1.653 inch) that saves more than 70% of installation space compared to miniature circuit breakers
  • Nominal current assignable for each channel
  • Satisfy EN 60204-1 requirements for dependably switching off ground faults after five seconds


Communication 1.0
Digital Signaling (S/P)

The electronic circuit breaker can be reset via digital control signal. The 787-2861 ECB can also be switched on and off with this control signal. A digital output signal indicates the status of the channel or the sum of the channels for 787-166x ECBs. For some devices, this signal is potential-free (P).


Communication 2.0
Manchester Protocol (M)

The PLC transmits a coded pulse pattern to control input S1. The ECB synchronizes itself automatically. The current status of all output channels is transmitted back simultaneously via signal output S2. The edge change is interpreted as “high” or “low.” For each channel, both status and voltage/current values can be transmitted individually.


Communication 3.0
IO-Link (I)

Via an IO-Link interface implemented in COM3, for each channel, both its status and its voltage and current values can be transmitted individually. The nominal output current can also be configured via this interface if the device's rotary switch is set accordingly. The IO-Link cyclic communication is much faster than the Manchester protocol.


S = Signal
P = Potential-free signal
I = IO-Link protocol
M = Manchester protocol

Get In Touch