WCQ2C Series 3P Automatic Transfer Switch

It is the three-pole member of Westhomes' WCQ2C ATS family, an electrically operated switch that automatically transfers a three-phase load between the utility mains and a standby generator (or second feed). The 3P version switches the three phase conductors while keeping the neutral continuous, making it suitable for three-phase systems with a shared neutral.

Choose 3P when the neutral is shared between the two sources — for example, two utility feeds, or a generator whose neutral is not separately bonded from the mains. Choose 4P instead when the standby generator has its own neutral-to-earth bond (separately derived system) and local rules require the neutral to be switched to prevent parallel earth paths.

It is widely used in factories, small commercial buildings, offices, retail stores, water treatment plants, telecom base stations, and healthcare facilities to back up three-phase loads such as HVAC, pumps, compressors, machine tools, lifts, and distribution boards. It is not meant to break short-circuit currents — upstream breakers provide fault protection.

The WCQ2C series covers common three-phase frame sizes, typically from 16A up to 100A in this compact class (with higher-frame ranges available in larger series). Select the rating to match the full load current with a safety margin, and account for motor inrush and transformer magnetising current during sizing.

The controller continuously monitors voltage, frequency, and phase balance on both sources. On a mains fault it waits for the transfer delay, energises the generator start contact, verifies the generator has reached rated voltage and frequency, then opens the mains contacts and closes the generator contacts. When mains returns and holds up for the re-transfer delay, the load is transferred back and the generator is stopped after a cool-down timer.

The mechanical transfer time is typically under 100 ms to a few hundred milliseconds (open transition). End-to-end interruption depends on generator start-up, usually 5–15 seconds. Adjustable on/off delays allow short sags to ride through without exercising the generator, which extends engine life.

Mount the ATS in or next to the main distribution board. Connect L1/L2/L3 from Source 1 and Source 2 to the inputs, and the same phases to the load output; neutral remains continuous on the 3P version. Run the generator control wires in separate conduit, verify phase rotation matches between sources, and earth the enclosure per local code. Commission with a full functional test under load.

Yes. The WCQ2C 3P supports automatic mode plus local pushbutton selection and a manual operating handle for service or emergency use. Auxiliary contacts are available to feed remote indication (source selected, fault, generator running) into a building management system or SCADA.

The series complies with IEC 60947-6-1, the IEC product standard for low-voltage transfer switching equipment up to 1000 V AC, covering construction, ratings, dielectric and short-time withstand, and making/breaking duty. CE marking is standard, with additional market-specific certifications available on request.

A manual 3P changeover is a simple lever-operated interlocked switch with no sensing or automation, so every transfer requires an operator and cannot start a generator. The WCQ2C 3P is a self-contained automatic system that detects faults, starts and stops the generator, and transfers the load unattended. It costs more but is essential for critical, unmanned, or emergency-backed three-phase loads.