Doepke Type B RCCB - DFS4B
Many electrical installations now contain products which incorporate power electronics, such as inverters for PV installations, speed control in HVAC, some running machines, UPS, medical equipment etc. This type of equipment can produce, in addition to standard 50Hz earth leakage currents, pure DC and high frequency AC leakage currents which would not be detected by a standard AC or A type RCD. 'B' type RCDs in addition to normal AC, can detect high frequency AC and pure DC earth leakage curents
A comparison of the AC-DC sensitive residual current ciruit-breaker
Many standards, regulations and directives demand the provision of a Type B AC-DC sensitive residual current circuit-breaker (RCCB).
Wherever three-phase electronic equipment is connected to mains without electrical isolation, AC-DC sensitive residual current circuit-breakers must be employed. There are, however, also cases in the 240 V mains network where they are applicable, e.g. photovoltaic (solar energy) installations with inverters lacking a transformer.
Pumping stations, air conditioning and ventilation facilities, escalators, welding equipment, medical-technical equipment, UPS and photovoltaic installations, agricultural and work premises with potential fire hazard, lecture rooms with experimentation facilities, exhibitors mobile displays. These are a few examples where - because mainly pulsed equipment is employed for the power control in such installations (e.g. frequency converters) - the use of residual current circuit-breakers is imperative.
To select the correct RCCB for each individual application, we offer you three different tripping characteristics within the area of AC-DC sensitive RCCBs.
In many electrical installations, such as e.g. in construction site power distributors, fire protection plays a secondary role. Here it is often the case that only fault protection and high availability of plant are demanded. Due to the lower response sensitivity at higher frequencies, there are few equipment-related unwanted tripping incidents. The devices in the SK model range conform to VOE Standard 0664-100 E.
The B+ model range is based on the new VDE Standard 0664-110. Compared to residual current circuit breakers of the SK model range, these devices will trip when residual currents up to max.20 kHz occur within an upper response limit of 420 mA and offer a higher preventative fire protection.
The NK model range guarantees classic fire protection from 300 mA at frequencies up to one megahertz (1 MHz) and thereby substantially exceeds the requirements of the Standard for Type B+ residual current circuit-breakers (RCCBs). It is thus the optimum protection for installations with residual currents at frequencies in excess of 20 kHz.