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.

WAGO’s ECBs have a lot to offer:

  • They provide reliable protection against overload and short circuits.
  • They also allow switch-on of high-capacitance loads of 50,000 μF and more, without increasing the rated current setting.
  • One-, two-, four- and eight-channel models and current ratings from 0.5 to 12 A offer you the flexibility you need for setting the rated current to suit your specific application.
  • 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.


Electronic Circuit Breakers from WAGO

Precise Protection and Space Savings for DC Circuits

Discover the advantages of WAGO’s ECBs over conventional circuit breakers. If the power supply cannot temporarily provide high excess current, then fuses and conventional circuit breakers often prove ineffective for selective protection of individual current paths on the secondary side.

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.

New Product

Protecting Small Currents Easily

New WAGO 0.5 A Electronic Circuit Breaker

With WAGO’s single-channel 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 for more convenient use. The digital output reports the current status. The fact that they have the same profile allows direct commoning of the input and output voltages 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) design saves space
  • Reliable tripping of the circuit breaker after just 4 ms

Discover More Electronic Circuit Breakers

Single-Channel Electronic Circuit Breakers (ECBs)

The new modules are just 6 mm (0.236 inch) wide, making them the slimmest ECBs currently available on the market. They are approximately 66 % smaller than miniature circuit breakers, saving even more space, particularly when used in control cabinets. These ECBs allow high-capacitance loads greater than 50,000 μF to be switched on – helping you reduce false tripping due to inrush currents.

The Benefits for You:

  • 24 VDC; six versions available for rated currents from 1 to 8 A
  • Devices color coded according to rated current
  • An extremely slim design
  • Switch-on capacity: > 50,000 µF
  • Wide surrounding air temperature range: −25 … +70 °C (−13 … +158 °F)
  • Resetting and on/off switching directly on the module or remotely via digital input signal
  • Triggered signal output – can also be commoned 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 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.

The Benefits for You:

  • 2-, 4- and 8-channel circuit breaker 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, precise disconnection in the event of overcurrent or short circuit


Models differentiated visually

Devices color coded by rated current


Simple wiring

Signal output can be commoned 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, markable cover



Fast, 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 such as 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, the Machinery Directive EN 60204 requires detecting hazardous ground faults in control circuits and switching them 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:

  • Found in NH fuses, DP fuses
  • High overcurrents required for fast tripping


  • In the example: ten-fold overcurrent (with respect to the fuse’s nominal current): tripping within the range of 30 ms (best case) or 200 ms (worst case)
  • Only two-fold overcurrent: tripping within the range of 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:

  • Precision setting options
  • Reaction within a short time, even with 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 Work?

The ECB checks whether 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 tripping time depends on the magnitude of the overcurrent. The measurement of the output current, the processing and calculation of the tripping time and the actuation of the semiconductor switch are performed by a microprocessor that monitors one or more output channels. The corresponding tripping times can be found in the graph on the right.


Advantages of ECBs

  • Switch off secondary-side overcurrents and short circuits – even with long cable runs and small conductor cross-sections – with precision, speed and repeatability
  • Selectivity, especially with ECBs with active current limitation
  • Remote operation via digital input and output
  • Fast and reliable communication via IO-Link protocol, signal contact, potential-free signal or Manchester protocol
  • Advantageous installation size and width, for example, eight output channels in just 42 mm (1.653 inch) (which saves more than 70 % of installation space compared to miniature circuit breakers)
  • Nominal current can be set 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 a 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 its status and its voltage/current values can be transmitted individually.


Communication 3.0
IO-Link (I)

For each channel, both its status and its voltage/current values can be transmitted individually via an IO-Link COM3 interface. 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

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