Date: 2026-08-19
The electrical panel contains various protective devices, each of which has a specific function. The circuit breaker, the residual current device, the residual current device and the surge protector are not interchangeable.
To make the right choice, you must know the purpose of the individual devices, the characteristics of the electrical installation, and the loads that will be powered.
1. Circuit breaker – overload and short circuit protection
A circuit breaker, also known as an MCB, protects electrical circuits and wires from overload and short circuits. It shuts off the power when the current exceeds the permissible values for the circuit.
When selecting, the rated current, number of poles, tripping characteristics, breaking capacity and conductor cross-section are checked. A higher rated current does not automatically mean better protection.
The circuit breaker must be compatible with the permissible current load of the conductors and the characteristics of the load.
2. Residual current protection – leakage current protection
Residual current protection, also known as a residual current device or RCCB, monitors the difference between the currents in the active conductors. If a leakage current above a set value is detected, the device disconnects the power supply.
The main characteristics when choosing are the rated current, the rated differential current, the type of protection and the number of poles.
It is important to know that the standard RCCB does not provide protection against overload and short circuit on its own. Therefore, it must be properly coordinated with appropriate overcurrent protection.
3. Residual current circuit breaker – two functions in one device
A residual current device, referred to as an RCBO, combines the functions of a circuit breaker and a residual current device. It protects the corresponding circuit against overload, short circuit and leakage current.
RCBO allows individual electrical circuits to receive their own combined protection. When selecting, the rated current, tripping characteristic, residual current, type, number of poles and breaking capacity are again checked.
4. Impulse surge protection
A surge protection device, referred to as an SPD, has a different function. It is used to limit short-term surges that can occur due to atmospheric effects or switching processes in the electrical network.
An SPD does not replace a circuit breaker, residual current device or RCBO. Its selection and coordination depend on the electrical installation, the earthing system, the level of protection and the location of the device.
5. How to combine protective devices
Several types of protection can be used in one electrical panel because they react to different dangerous conditions:
- the circuit breaker protects against overload and short circuit;
- the residual current protection reacts to leakage current;
- An RCBO combines overcurrent and leakage current protection;
- SPD limits impulse surges.
The specific scheme depends on the number of circuits, the characteristics of the loads, the type of power supply network and the requirements for the installation.
6. What should we check before choosing?
- is the installation single-phase or three-phase;
- what loads will be powered;
- what is the cross-section of the wires;
- what nominal current is permissible for the respective circuit;
- is leakage current protection necessary;
- is surge protection necessary?
- what are the requirements for selectivity and coordination;
- what free modules are there in the electrical panel.
Summary
There is no single device that can replace all other types of electrical protection. The right solution usually involves a coordinated combination of devices, selected according to the specific installation and its consumers.
Browse the categories with circuit breakers , RCCB residual current devices and RCBO E.NEXT residual current devices .
Important: the design, selection, installation and inspection of protective devices must be carried out by a qualified electrician according to the characteristics of the installation and the current requirements.