WCQ2G-100 4P Dual Power Automatic Transfer Switch

The WCQ2G-100 4P is a four-pole automatic transfer switch that switches all three phases plus the neutral conductor between two three-phase power sources. It is used in installations where the standby generator is a separately derived system with its own neutral-to-earth bond, so the neutral must be isolated when switching to avoid parallel neutrals and earth-loop currents.

A 3P ATS keeps the neutral continuous, which is fine when both sources share a single neutral-earth reference. A 4P ATS opens and closes the neutral together with the phases, preventing the generator neutral and the mains neutral from being paralleled. This is required by many wiring rules when the standby generator has its own N-E bond, and it improves safety during fault conditions.

Common uses include standby generator backups for commercial buildings, small factories, clinics, offices, and any three-phase installation with a separately earthed generator. It is also used where two utility feeds (main and emergency) must be kept fully isolated on the neutral, or where local regulation mandates switched neutral for emergency supplies.

The "100" in the model name denotes a 100A frame size. Within that frame, Westhomes typically offers trip/setting ratings from 16A up to 100A (e.g., 16, 20, 25, 32, 40, 50, 63, 80, 100A). You select the rating that matches your load current with appropriate margin, especially for motor starting and transformer inrush.

The control unit continuously monitors voltage, frequency, and phase balance on both sources. On a fault it waits for the set transfer delay, closes the generator start contact, waits until generator voltage and frequency are stable, then breaks all four poles (L1/L2/L3/N) from the mains and makes them to the generator. When mains returns and stays stable for the re-transfer delay, the load moves back and the generator is stopped after a cool-down period.

The actual switching contact time on this class of ATS is typically under 100 ms to a few hundred milliseconds (open transition). The perceived outage length is mostly determined by the generator start-and-stabilise time, commonly 5–15 seconds. Delays are adjustable so you can ignore very short sags rather than cycling the generator.

A qualified electrician mounts it in a distribution panel, runs L1/L2/L3 and N from both sources to the input terminals, and connects the same four conductors to the load output. The enclosure is earthed separately, and the neutral must not be re-bonded on the load side in a way that bypasses the switched neutral. The generator control wires are run in separate conduit from power cables.

Yes. The WCQ2G-100 4P combines automatic operation with local pushbutton control and a manual handle. Maintenance staff can force a source selection, test the switching mechanism, or lock the switch in a position for safe service. Automatic mode is re-engaged once testing is complete.

The product is designed to IEC 60947-6-1, the IEC standard for transfer switching equipment up to 1000 V AC, covering ratings, impulse withstand, short-time current, and making/breaking duty. It is normally CE-marked, and type-test reports can be supplied for project certification. Installation must still comply with local wiring regulations (e.g., IET / NEC equivalents).

A manual 4P changeover is a low-cost lever device that needs an operator to move the handle between positions and cannot start a generator. The WCQ2G-100 4P adds sensing electronics, an electric actuator, and a controller that runs the whole transfer sequence unattended. It is the right choice for critical or unmanned loads; the manual version is only suitable for attended sites where someone can respond immediately to an outage.