WSB132B-030 RCBO Residual Current Breaker

The WSB132B-030 is a single-phase RCBO (Residual Current operated circuit Breaker with Overcurrent protection) that protects branch circuits against earth leakage, overload and short-circuit faults. With a 30mA residual current sensitivity, it is primarily intended to prevent fatal electric shock from direct or indirect contact with live parts. It combines the functions of an RCD and an MCB into a single compact DIN-rail module for 230V household and commercial installations.

Line and neutral conductors both pass through a toroidal differential current transformer. Under normal conditions, the current going out on L equals the current returning on N, and their magnetic fluxes cancel — the core flux is zero. When a person touches a live part or insulation fails, some current leaks to earth through an unintended path, creating an imbalance. The transformer detects this imbalance, and once it reaches 30mA, an electronic or electromagnetic release triggers the trip, opening the contacts in milliseconds.

The WSB132B-030 is rated for AC 230V (±10%), 50/60Hz, with a rated residual operating current (IΔn) of 30mA. It is offered in several nominal current ratings (In), commonly 6A, 10A, 16A, 20A, 25A, 32A and 40A (up to 63A on selected models), with tripping curves B or C and a rated breaking capacity (Icn) of 6kA. The pole configuration is 1P+N, and the standard DIN-rail housing is typically 2 modules wide (some compact versions are 1 module).

A 30mA tripping level is internationally accepted (IEC 60755, IEC 61009) as the threshold that will trip fast enough (typically within 30ms at 150mA or less) to prevent ventricular fibrillation from a 50/60Hz current passing through the human body. Higher sensitivities (10mA) are used in special locations such as bathrooms or swimming pools, while lower sensitivities (100/300/500mA) are reserved for fire prevention and upstream selectivity rather than direct-contact personal protection.

The standard WSB132B-030 is typically Type AC, which trips on sinusoidal alternating residual currents. If the installation contains electronic equipment such as variable-speed drives, UPS systems, EV chargers, solar inverters or dimmer switches that can produce pulsating or smooth DC residual currents, a Type A (or Type F/Type B) variant should be selected — Type AC devices may fail to detect pulsating DC leakage and therefore not provide adequate protection. Confirm the exact trip type with the supplier datasheet.

Mount the unit on a 35mm DIN rail inside a weather-protected distribution box. Connect supply L to the marked "IN L" terminal, supply N to "IN N", and connect the branch circuit to the corresponding OUT terminals. Never pass the neutral conductor outside the sensing core, and never connect earth (PE) to any terminal on the RCBO. Ensure conductors are rated for the current rating and that terminations are properly torqued. After installation, press the T button to verify correct operation before loading the circuit.

Tripping can be caused by: (1) a genuine earth fault — an appliance or cable leaking current to earth; (2) overload — too much load on the circuit; (3) short circuit; (4) nuisance tripping from high-frequency leakage (LEDs, inverters, EV chargers) or surges; or (5) an aging / defective RCBO. Diagnosis steps: reset and see if it trips immediately (fault present), under load (overload), or randomly (nuisance). Disconnect loads to localize the fault, and use a RCD tester and residual-current clamp meter for quantitative measurement.

The WSB132B-030 is designed and tested to IEC 61009-1 (RCBO for household and similar purposes) and references IEC 60898-1 for overcurrent characteristics. It typically carries CE marking and may be certified under the CB scheme for international acceptance. For specific countries, supplementary marks such as UKCA, VDE, KEMA, or CCC may be available depending on production line — always request the relevant test certificate (CB report / certificate) before bulk installation.

This RCBO is suitable for final circuits in homes, apartments, villas, offices, retail stores, schools, hospitals and light industrial panels. Typical loads include socket outlets, fixed appliances, lighting, kitchen circuits, bathroom circuits, and outdoor equipment. It should not be used as the sole protection for three-phase equipment — use a 4-pole (3P+N) RCBO/RCCB for three-phase loads. For medical locations or wet areas, select higher-sensitivity (10mA) or Type A/F/B variants as required by local codes.

Press the T (test) button at least every six months (monthly in damp or coastal environments) — the RCBO must trip instantly. After resetting, listen for a firm mechanical click. Annually, check that all terminals are tight, the housing is not discolored or deformed, and the device is not running hot under load. Every 2–3 years, have a qualified electrician verify tripping characteristics with a RCD test instrument. If the unit fails the self-test, has visibly degraded contacts, or has interrupted a major fault, replace it — never attempt to repair or dismantle it.