RCB
RCDs: residual current protection for people, equipment and low-voltage installations.
- Protection: disconnects circuits in the event of residual current leakage.
- Classes: AC, A, B and super-immunised versions.
- Sensitivity: 30mA and 300mA options according to application.
- Formats: 2P and 4P devices for single- and three-phase boards.
Residual current devices: classes, sensitivity and selection criteria
Solera residual current devices (RCDs) detect residual currents and disconnect the circuit when their operating conditions are reached. For residential, office and commercial boards, selection depends on the residual-current waveform, sensitivity, rated current and network configuration. The S24 ranges include Type AC, A and B devices, high-immunity Type A devices and an automatic reconnection solution.
What distinguishes each S24 range
| Range | Distinctive function | What to check |
|---|---|---|
| Type AC | Sinusoidal AC residual current detection | Suitability for the circuit’s loads |
| Type A | Sinusoidal AC and pulsating DC | Possible DC components from the load |
| Type B | Includes smooth DC detection | Equipment and system requirements |
| High immunity | Type A with increased immunity to disturbances | Cause of tripping and residual-current type |
| Automatic reconnection | Adds resetting; S24DR2P4030 is Type AC | Operating mode and retry sequence |
How to compare references
Do not confuse rated current in A with rated residual operating current IΔn in mA. For example, 40 A and 30 mA describe different characteristics. Also check poles, voltage, modules, neutral position and coordination with overcurrent protection. An RCD without integral overcurrent protection does not replace an MCB.
For electronic loads, inverters or charging equipment, consult the equipment manufacturer’s required RCD type. The application alone does not establish compatibility. Individual specifications and instructions provide the mounting and maintenance conditions.
Frequently asked questions
Does a 40 A RCD trip in response to a 40 A overload?
Its rated current does not make it an overload protection device. These ranges provide residual current protection; overload and short-circuit protection must be provided and coordinated using appropriate devices.
Are 30 mA and 300 mA interchangeable?
No. They are different sensitivities: 30 mA responds to a lower residual current. Changing to 300 mA alters the protection and is not a remedy for unwanted tripping. Sensitivity must suit the design and applicable requirements.
Does high immunity mean Type B or automatic reconnection?
No. High immunity improves resistance to certain disturbances; Type B describes detection capability, and automatic reconnection adds a resetting function. Each characteristic must be specified for the selected reference.