

The Cirprotec V-CHECK 2MP-D-25 + CS21 surge protector, reference 77706395C, is a protection assembly for single-phase electrical installations that combines protection against permanent overvoltages, a 25 A automatic main circuit breaker (IGA), and Type 2 transient overvoltage protection. Its 1P+N configuration is especially suitable for electrical panels in homes, commercial premises, and other 230 V single-phase installations.
The assembly consists of the V-CHECK 2MP-D-25 permanent overvoltage protector, with integrated 25 A C-curve MCB, and the CS21-15/230 transient protector. In this way, a single solution can act against sustained voltage increases and limit very short-duration transient spikes associated with electrical switching operations or indirect effects of lightning strikes.
The reference 77706395C combines two complementary types of protection:
This combination helps protect both the installation wiring and the electrical and electronic equipment connected downstream.
The V-CHECK 2MP-D-25 incorporates a 25 A thermal-magnetic circuit breaker with C curve. The unit is factory prewired to simplify installation and reduce additional connections inside the panel.
The C curve is common in distribution circuits with loads that may generate moderate inrush currents. The breaking capacity associated with this family is 6 kA according to UNE-EN 60898.
The V-CHECK module is designed to detect abnormal and sustained increases in mains voltage. This type of overvoltage can occur, among other causes, due to issues related to the neutral conductor and can subject electrical receivers to a voltage higher than expected for an extended period.
When a permanent overvoltage condition is detected in accordance with the curve established by the device, the system trips the integrated circuit breaker and disconnects the protected installation.
Cirprotec identifies the V-CHECK MP-D range as domestic protection against POP permanent overvoltages in accordance with UNE-EN 50550 and with built-in circuit breaker.
The solution is especially intended for protection panels in low-voltage installations where integrated permanent overvoltage monitoring and thermal-magnetic protection are required.
The 77706395C assembly adds a Cirprotec CS21-15/230 surge protector, classified as Type 2 according to EN 61643-11 and Class II according to IEC 61643-11.
The CS21 has a maximum discharge current Imax of 15 kA with an 8/20 µs waveform and is designed to limit transient overvoltages in low-voltage electrical panels.
The CS21 uses an internal 1+1 configuration with 2 poles, specifically designed for single-phase installations with phase, neutral, and protective conductor.
The protection modes are L-N and N-PE, providing coordinated protection between phase and neutral and between neutral and earth.
Cirprotec specifies the CS21-15/230 for TT and TNS network configurations. Installation must be carried out in accordance with the connection diagram indicated by the manufacturer, paying special attention to the neutral conductor and the PE protective connection.
The CS21 protector operates with a rated voltage of 230 V AC at 50-60 Hz. Its maximum continuous operating voltage is 275 V between phase and neutral.
These characteristics make it suitable for conventional low-voltage single-phase panels compatible with the indicated configuration.
For the transient protection module, Cirprotec specifies a protection level Up ≤1.2 kV between phase and neutral and ≤1.5 kV between neutral and earth.
The Up level represents the residual voltage that appears during protector operation under the specified test conditions and is an important parameter for coordinating protection with downstream equipment.
The CS21 transient protector has an Isccr short-circuit capacity of 10 kA and Cirprotec specifies a maximum upstream fuse of 63 A type gG for this module.
Final coordination with overcurrent protection devices must be carried out in accordance with the scheme and the actual characteristics of the installation.
The CS21 incorporates a dynamic thermal disconnection system that allows the protection element to be internally isolated when it reaches end-of-life or an abnormal operating condition.
This function helps maintain safe device performance throughout its service life.
The transient overvoltage module features visual indication via LED, making it easier to check its status during inspection and maintenance operations.
The standard CS21-15/230 reference used in this assembly does not include remote signaling contact.
The single-phase V-CHECK occupies 3 DIN modules and the compact CS21 only 1 additional module. The assembly therefore requires approximately 4 modules of space in the electrical panel.
Both components are ready for DIN rail mounting, making it easy to integrate them alongside the rest of the installation’s modular protection devices.
One of the standout features of the CS21 is its extremely compact monobloc format. It integrates its 2 protection poles into just 1 DIN module, allowing Type 2 protection to be added without taking up the usual space of a conventional bipolar surge arrester.
The CS21 accepts:
The conductor cross-section used must be determined according to the characteristics of the installation and Cirprotec’s instructions.
The transient module is designed to operate between -40 and +85 °C and with relative humidity between 5 and 95%.
Its enclosure is made of polycarbonate, has UL94 V-0 flammability classification, and features a RAL 7035 grey finish.
The Cirprotec 77706395C combines in a single assembly a 25 A C-curve MCB, protection against permanent overvoltages, and a Type 2 surge arrester with Imax of 15 kA. In this way, it covers different electrical risks with a modular solution especially suitable for single-phase panels.
The prewired V-CHECK simplifies installation of permanent overvoltage protection, while the compact CS21 adds transient protection while occupying only one DIN module. The result is a solution of approximately 4 modules for homes, premises, and other compatible installations.
Important: although the provided title only mentions protection against permanent overvoltages and the 25 A MCB, the full reference 77706395C is sold as an assembly with the 15 kA CS21 transient protector. Installation must be carried out following Cirprotec’s diagram and by qualified personnel.