High Immunity RCBO – 40A C Curve, Type A, 30mA (WER40C-030)
18th Ed. Compliant
2-Year Warranty
UK Stock
Free Delivery £80+
Secure Payments With
The WER40C-030 is a 40A C Curve Type A High Immunity RCBO designed for circuits with higher inrush characteristics, modern electronic loads and equipment where nuisance tripping may be more likely. It is commonly specified for suitable EV charger circuits, heat pumps, motors and inverter-fed equipment. This RCBO combines overload...
The WER40C-030 is a 40A C Curve Type A High Immunity RCBO designed for circuits with higher inrush characteristics, modern electronic loads and equipment where nuisance tripping may be more likely. It is commonly specified for suitable EV charger circuits, heat pumps, motors and inverter-fed equipment.
This RCBO combines overload protection, short-circuit protection and 30mA residual current protection in one device. With 10kA breaking capacity, double pole disconnection and bi-directional wiring, it gives installers a practical option for heavier-duty single-phase circuits requiring a 40A C Curve RCBO.
Installer note: Choose the C Curve version where the circuit has higher inrush demand. For lower inrush domestic circuits, the 40A B Curve RCBO may be more appropriate.
- 40A C Curve Type A RCBO – combined overload, short-circuit and earth leakage protection
- High immunity design – helps reduce unwanted tripping on modern electrical loads
- 30mA residual current sensitivity – suitable for final circuit protection where specified
- 10kA breaking capacity – suitable for more demanding installations
- Double pole disconnection – isolates live and neutral together
- Bi-directional wiring – allows flexible line and load connection
- Type A leakage detection – responds to AC and pulsating DC residual currents
- BS EN 61009 compliant – recognised standard for RCBO protection
When to Use a 40A C Curve RCBO
A C Curve RCBO is typically used where the connected equipment may draw a higher short-duration startup current. This makes it better suited than a B Curve RCBO for some motor-driven, inverter-fed or higher-demand circuits.
For installers, the key point is matching the curve, current rating and residual current type to the actual circuit design. The WER40C-030 is a strong choice where a 40A Type A RCBO is required and the load characteristics make C Curve protection more suitable.
B Curve vs C Curve RCBO
| RCBO Curve | Typical Use | Best Fit |
|---|---|---|
| B Curve | Lower inrush circuits | General domestic final circuits |
| C Curve | Higher inrush circuits | EV chargers, motors, heat pumps and inverter-fed equipment where specified |
Compare High Immunity RCBOs
| Model | Rating | Curve | Typical Use |
|---|---|---|---|
| WER06B-030 | 6A | B | Lighting and other low inrush final circuits |
| WER06C-030 | 6A | C | Low-rated circuits where higher inrush tolerance is preferred |
| WER16B-030 | 16A | B | General domestic final circuits with low inrush loads |
| WER16C-030 | 16A | C | Small motors and circuits with moderately higher inrush current |
| WER20B-030 | 20A | B | Domestic final circuits requiring a higher current rating |
| WER20C-030 | 20A | C | Circuits with moderately higher inrush current |
| WER32B-030 | 32A | B | Ring finals and other standard appliance circuits |
| WER32C-030 | 32A | C | Higher demand circuits and loads with greater inrush current |
| WER40B-030 | 40A | B | Higher load circuits with lower inrush characteristics |
| WER40C-030 (This Product) | 40A | C | Heavier-duty circuits with higher inrush conditions |
| WER63C-030 | 63A | C | Larger commercial or high-load applications |
When should I specify a 40A C Curve RCBO?
A 40A C Curve RCBO is typically used where the circuit has higher inrush characteristics, such as suitable EV charger circuits, motors, heat pumps and some inverter-fed loads.
What is the difference between B Curve and C Curve RCBOs?
B Curve RCBOs are generally used for lower inrush circuits. C Curve RCBOs tolerate higher short-duration startup currents, making them more suitable for some motor-driven or inverter-fed circuits.
Is this RCBO bi-directional?
Yes. The WER40C-030 has bi-directional wiring, allowing flexible line and load connection where installed correctly.
What does high immunity mean on an RCBO?
High immunity means the RCBO is designed to better resist unwanted tripping caused by transient conditions, harmonics and switching events on modern electrical loads.
Is this suitable for EV charge points?
Yes, where a 40A C Curve Type A RCBO matches the EV charger circuit design. Where PME protection is also required, see our PME fault detection range.
Does this RCBO isolate live and neutral?
Yes. It provides double pole disconnection, isolating live and neutral together.
- Model: WER40C-030
- Product Type: High Immunity Type A RCBO
- Current Rating: 40A
- Trip Curve: C Curve
- Residual Current Sensitivity: 30mA
- Breaking Capacity: 10kA
- Disconnection: Double pole
- Leakage Type: Type A – AC and pulsating DC residual current detection
- Wiring: Bi-directional
- Application: EV chargers, heat pumps, motors and inverter-fed circuits where specified
- Standards: BS EN 61009 / IEC 61009
This 40A C Curve high immunity RCBO should be selected where the circuit design, load current and inrush characteristics suit a 40A C Curve device. Final specification and installation must be carried out by a qualified electrician.
- DIN rail mounted
- Check that the 40A rating matches the circuit design and cable sizing
- C Curve format suits circuits with higher inrush characteristics
- Type A residual current detection covers AC and pulsating DC leakage
- Bi-directional wiring allows flexible line and load connection
- Double pole disconnection isolates live and neutral together
