High Immunity RCBO – 40A C Curve, Type A, 30mA (WER40C-030)

The WER40C-030 high immunity RCBO combines 40A C-curve overcurrent protection and 30mA Type A residual current protection in a two-module device. With 10kA breaking capacity, switched live and neutral and separate black and white operating handles, it provides circuit protection with a useful fault-finding indication for the electrician.

Choose this model when the circuit design specifies 40A, C curve and Type A protection. Check all three: C curve describes the overcurrent trip characteristic, while Type A describes the residual current waveforms detected. They are separate parts of the specification.

Practical benefits on site

• Twin handles help identify the fault type: Whitecliffe states that the black handle alone tripping indicates an overload or short circuit; both handles tripping indicates a residual current fault. This gives the electrician a useful starting point for diagnosis.
• Switched live and neutral: both conductors are disconnected when the device operates.
• Combined protection in one device: overload, short-circuit and residual current functions in the same RCBO.
• Two-module DIN-rail format: allow the required space and check the board and busbar compatibility before selecting it.

Check the curve and residual current type

C-curve devices can suit loads with higher starting currents when the circuit design permits them. A C curve is not an automatic upgrade from B curve or a cure for an unexplained trip: fault protection, cable sizing and the connected equipment must all be checked.

Type A detects AC and pulsating DC residual currents. It is not Type B protection and does not provide a separately specified 6mA smooth-DC detection function. For an EV charger, heat pump or other inverter-based load, confirm the equipment manufacturer's required protection before choosing this RCBO.

Gallery note: the images illustrate the WER range and include other ratings and curves. This listing is for WER40C-030, marked C40; the B40-marked device shown is a different variant.

Compare closely related WER RCBOs

These three variants share Type A, 30mA protection and the WER two-module format. Select the current rating and curve from the circuit design; do not substitute a variant solely because it is available.

Check availability or the correct variant

contact Power & Data UK quoting WER40C-030, the board model, required quantity and delivery date. If this item is shown as unavailable, ask for the current lead time. For technical details, view the Whitecliffe WER datasheet.

• Product code: WER40C-030
• Manufacturer / range: Whitecliffe / WCED WER high immunity RCBO
• Rated current / trip curve: 40A / C curve
• Residual current protection: Type A, 30mA; AC and pulsating DC detection
• Rated breaking capacity: 10kA
• Poles / disconnection: two-pole; switched live and neutral
• Width / dimensions: two-module format; manufacturer-listed 35 × 82 × 77mm (W × H × D)
• Rated voltage / frequency: 230/240V AC, 50/60Hz
• Operating principle: electromagnetic
• Fault indication: twin black MCB and white RCD handles
• Mounting: 35mm DIN rail, EN 60715
• Connection: top or bottom supply connection listed in the datasheet; follow the supplied instructions
• Terminal capacity: up to 25mm² cable / 10mm² busbar, per manufacturer data
• Terminal tightening torque: 2.5Nm, per manufacturer data
• Product standard: EN 61009-1 / IEC 61009-1
• Protection degree: IP20; requires a suitable assembly/enclosure for the installation

Download the Whitecliffe WER datasheet

Final device selection, installation and testing must be completed by a qualified electrician using the supplied WER instructions and the board manufacturer's requirements.

• Confirm the 40A rating and C-curve characteristic against the load, cable sizing and required fault disconnection performance.
• Check the prospective fault current against the device's 10kA breaking capacity and the complete assembly design.
• Confirm Type A, 30mA protection meets the equipment requirements; assess any separately required smooth-DC protection.
• Allow two-module space and confirm mechanical, busbar and electrical compatibility with the distribution board.
• Follow the supplied terminal markings and connection instructions. Manufacturer data lists top or bottom connection and 2.5Nm terminal torque.
• Complete the required commissioning tests; investigate a trip before resetting and returning the circuit to service.

What is the difference between C curve and Type A?

C curve is the overcurrent trip characteristic. Type A describes residual current detection for AC and pulsating DC waveforms. WER40C-030 combines both; C curve does not mean Type C residual current protection.

How do the black and white handles help with fault finding?

Whitecliffe identifies the black handle as the MCB function and the white handle as the RCD function. Black alone tripping indicates overload or short circuit; both tripping indicates a residual current fault. The cause should be investigated before the circuit is returned to service.

Is this a single-module RCBO?

No. WER40C-030 is a two-module device. Check available DIN-rail space and the board manufacturer's compatibility requirements before ordering.

Can it be supplied from the top or bottom?

The WER datasheet lists connection from the top or bottom. Follow the instructions and terminal markings for the supplied device, and confirm suitability where the application involves reverse power flow.

Can I use it for an EV charger or heat pump?

Only where the equipment instructions and electrical design specify this combination of 40A, C curve and Type A protection. This RCBO does not replace required Type B protection, separate DC detection or any other protection specified for the installation.

Will high immunity stop nuisance tripping?

It is the manufacturer's designation for this WER range, not a guarantee that a circuit will never trip. Existing faults, leakage and incorrect device selection still need investigation.

Why does the photograph show B40?

The gallery contains WER range images of other variants. The product supplied against this listing is WER40C-030, the 40A C-curve version. Check the product code and C40 marking when verifying the delivered device.