The tripping frequency response for the DFS 2 B and DFS 4 B type SK circuit-breakers has a tripping threshold up to 2 A at high frequencies. If system-specific, high-frequency leakage currents are expected, the SK characteristic curve ensures the highest possible system availability. Devices with this curve provide fire protection at frequencies up to 1 kHz. Residual current circuitbreakers with this characteristic curve therefore combine safety and cost-efficiency while protecting installations where system availability is the top priority.

DFS 2/4 B — reliable protective separation for smooth DC residual currents
and AC residual currents up to 150 kHz
—————— maximum surge current strength for maximum system availability
—————— flexible system retrofitting thanks to varying dimensions
—————— two-terminal residual current circuit-breakers
in compact housing of just two module wid


Electronic consumers and frequency converters with operating frequencies into the kilohertz range are now standard in electrotechnical installations. The residual currents that can occur in these installations may vary: in addition to conventional AC residual currents, smooth DC residual currents and AC residual currents with frequencies not equal to 50 kHz are becoming increasingly common. In this case, type A residual current circuit-breakers are no longer sufficient because they cannot detect these dangerous residual currents precisely. The VDE regulations and the safety rules of the professional association stipulate the use of type B residual current devices here.

Doepke developed the AC-DC sensitive DFS 2 B and DFS 4 B devices for the reliable, standard-compliant protection of installations – and of course the people who operate them. They have offered reliable protection against residual currents of all types for years.

High expertise for AC-DC sensitive solutions

Consider photovoltaic systems, charging columns for electric vehicles or single-phase frequency converters, where smooth DC residual currents may occur: each of these installations and applications requires a different type of protection. That’s why with the AC-DC sensitive residual current circuit-breakers from Doepke you can choose between different versions to cover all of your protection requirements. Even the installation dimensions are flexible: the DFS is available in just four module widths and now even comes in a compact housing that requires a mere two module widths. This makes retrofitting really easy, even when space is at a premium. Plus it goes without saying that all Doepke residual current circuit-breakers meet the DIN VDE 61008 device standard requirements. DIN VDE 0100 Part 530 serves as a useful guide when choosing a circuit-breaker and Doepke’s team of experts are very happy to help you determine which circuit-breaker is the best choice for your needs.

With the AC-DC sensitive DFS 2 B or DFS 4 B from Doepke, you can be certain that your system is equipped for the future when it comes to residual current protection. While your project’s immediate needs are more than covered, the high-quality AC-DC sensitive circuit-breaker delivers optimal protection for your electrical installation for years, no matter what equipment or devices are used in future.

The best fire protection with the DFS 2/4 B NK or B+

Need AC-DC sensitive residual current circuit-breakers that also meet requirements for preventative fire protection? Look no further than the devices in the DFS 2/4 type B+ or NK series. With type B+ devices the characteristic curve for the tripping frequency response runs below a tripping threshold of 420 mA at frequencies up to 20 kHz. The even more sensitive devices with the NK tripping characteristic offer a lower tripping threshold – with their conventional top limit of 300 mA they can even work at up to 150 kHz.

High system availability with the DFS 2/4 B SK-

–––––––––––––––––– tripping frequency response DFS 4 B SK; IΔn = 30 mA
–––––––––––––––––– tripping frequency response DFS 4 B+; IΔn = 30 mA
–––––––––––––––––– tripping frequency response DFS 4 B NK; IΔn = 30 mA


The selective series for even more control

Doepke has thought of every application in the development of its residual current circuit-breakers. Device versions with the “S” designation provide the option of selectively protecting installations with main and sub-distribution boards. A targeted layout of instantaneous conventional or AC-DC sensitive circuitbreakers can be arranged, allowing your customers to benefit from tiered system protection where only the faulty part of the installation is switched off.

The heavy duty version for tough environments

With Doepke’s AC-DC sensitive residual current circuit-breakers you have the right tools, even in extreme situations. Our HD (heavy duty) version is designed for use in tough ambient conditions. HD versions are especially protected against corrosion and are always the right choice in applications involving dust, humidity, corrosive gases or high temperatures up to 60 degrees.

If You Require Any Further Details

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