The circuit breaker and the surge protector are often housed in the same distribution panel, yet they are designed to address different hazards. Neither automatically replaces the other, and the exact configuration of the necessary protection must always be determined based on the building, the electrical system, and the connected equipment.
What is the function of a circuit breaker?
The residual current device (RCD), commonly known as an RCD or "Fi" relay, is an important component of protection against electric shock. During operation, it compares the current entering the circuit with the current returning from it. If the difference between the two values exceeds the set threshold, it can trip the affected circuit.
The RCD does not handle every fault or every overcurrent condition. Together with miniature circuit breakers, grounding, equipotential bonding, and other protective elements of the electrical system, it forms a system.
What is the purpose of surge protection?
A surge protective device (SPD) limits the effects of short-term, high voltage spikes that occur on the power grid. Such events can occur, for example, as a secondary effect of lightning activity or as a result of switching operations on the power grid.
The purpose of this protection is to reduce the risk to sensitive electronic equipment, control systems, and other electrical loads. The selection of the appropriate SPD type, rating, and wiring configuration depends on the network design and the building’s characteristics.
How do the two devices differ?
They are observing a different phenomenon
The ÁVK responds to the difference between the incoming and returning currents. The SPD diverts or limits the energy of overvoltage pulses, depending on its design.
They serve different purposes
The ÁVK is part of the protection against electric shock. The SPD primarily mitigates the effects of overvoltage events that threaten electrical equipment and control systems.
They work in conjunction with other protective elements
No single device is a standalone solution sufficient for every situation. A complete protection system also requires appropriate overcurrent protection, grounding, wiring, connections, and a design tailored to the specific application.
When should you check your existing security measures?
- before a major renovation or network upgrade;
- when installing new, sensitive, or high-value electronic equipment;
- when preparing to install a heat pump, solar panel system, electric vehicle charger, or smart home system;
- in the case of an old distribution panel and an unknown protection configuration;
- if you experience repeated disengagement or other abnormal operation.
The cause of the disconnection cannot be determined with certainty based solely on a description of the symptoms. An on-site inspection and, if necessary, measurements are required.
What can a specialist examine?
The scope of the inspection may vary depending on the task. This may include the design of the distribution panel, the presence and operation of the RCD, grounding and other safety measures, the type and wiring of the SPD, and the network documentation.
Before the inspection, it is a good idea to specify what equipment is in use at the property, whether any renovations have been done in the past, and what issues have been observed.
Summary
The RCD and the SPD do not perform the same function. The RCD is part of the protection against electric shock, while the SPD mitigates the effects of overvoltage events. The necessary protective solution must be designed or verified based on a thorough understanding of the entire electrical system.
Schedule an appointment to have your existing electrical protection system inspected.
