Tigo EI Automatic Transfer Switch TSS-200-US-G (200A with Generator Support)

The Tigo EI Automatic Transfer Switch (ATS) 801-200200-0301 is a required component for any Tigo EI grid-tied energy storage solution, combining a 200A main circuit breaker panelboard, built-in transformer, energy meter, and generator support in a single weatherproof enclosure. It continuously monitors grid power and automatically switches the home to solar, battery, or generator power within 500 milliseconds of a grid outage — then restores normal grid-tied operation when utility power returns. Designed for both outdoor and indoor wall-mount installation, this unit eliminates the need for a separate main panel upgrade by integrating the service disconnect directly into the ATS enclosure.

What's included

• 200A Main Circuit Breaker (MCB) Panelboard — integrated service disconnect eliminates the need for a separate main panel upgrade or derating
• Built-in Transformer — provides 120 VAC and 240 VAC split-phase output to support whole-home or essential-load backup
• Energy Meter — measures grid import and export with ±1% accuracy; data accessible via the Tigo EI mobile app and portal
• RS-485 Communications Module — enables monitoring and control integration with the Tigo EI system
• Manual Bypass Switch — allows manual control of transfer switching for maintenance or testing
• Generator Support (2-wire start) — controls a pure sine wave generator up to 24 kW via dry contact relay; switchover in under 500 msec.
• Not included: Tigo EI inverter and battery (sold separately), conduit and weatherproof fittings for cable entry, mounting hardware, generator (sold separately)

System specifications

• Grid input: 240 V nominal, 180–270 V operating range (L-L), up to 200 A maximum input current, 48,000 VA maximum power
• Backup output: 120/240 VAC split-phase, 11,400 W rated AC power, 48 A continuous current from backup
• Switchover time: grid to inverter in under 500 msec.; off-grid to generator in under 500 msec.
• Generator support: pure sine wave, up to 24,000 W, 100 A maximum continuous input, 2-wire start, 240 V / 60 Hz nominal
• Environmental rating: NEMA 4X / IP65 (dust and watertight); operating temperature -25°C to 50°C (-13°F to 122°F); operating humidity up to 100%
• Physical: 17.9 × 21.6 × 9.6 in. (455 × 550 × 245 mm); 65 lbs. (29.5 kg); wall mount; natural convection cooling
• Certifications: UL 1741, UL 869A, CSA 22.2 No. 107.1, CSA 22.2 No. 0.19
• Warranty: 11 years

Eliminate the need for a separate main panel upgrade

On-grid storage installations typically require derating or upgrading the home's main electrical panel to accommodate the additional load — a costly and time-consuming permitting process. The TSS-200-US-G integrates the 200A main circuit breaker and service disconnect directly into the ATS enclosure, removing that requirement entirely. Installers connect the utility feed, the Tigo inverter output, and the generator directly to the ATS — one enclosure handles grid monitoring, automatic transfer switching, generator control, and energy metering without additional hardware.

Who this unit is built for

• Tigo EI residential energy storage systems — required component for any Tigo EI grid-tied ESS; provides the automatic grid isolation and transfer switching that makes battery backup legally and functionally possible.
• Whole-home or essential-load backup installations — the 200A service capacity and split-phase output support either full-home coverage or a dedicated essential-load subpanel, depending on system design.
• Sites with generator backup requirements — the generator support model adds automatic generator start/stop control and seamless switching between battery-only and generator-assisted backup modes.
• Outdoor and exposed electrical installations — the NEMA 4X / IP65 enclosure is rated for direct weather exposure, humidity up to 100%, and elevations up to 9,842 ft. (3,000 m).
• Installations where panel upgrades are impractical — the integrated 200A MCB and service disconnect allow the ATS to replace the main panel function, avoiding costly utility coordination and permitting delays.

How the components connect

The utility feed connects to the ATS grid input, where the integrated 200A main circuit breaker serves as the service entrance disconnect. The Tigo EI inverter output connects to the inverter input port; the ATS continuously monitors grid voltage and frequency, and switches the output bus to inverter power within 500 milliseconds when a grid outage is detected. When a generator is connected, the ATS sends a 2-wire start signal via the dry contact relay, then switches from battery-only to generator-assisted backup in under 500 milliseconds once the generator reaches stable output. The built-in energy meter tracks import and export across all sources with ±1% accuracy, and the RS-485 communications module passes this data to the Tigo EI platform for real-time and historical monitoring through the Tigo EI mobile app and portal. Installers will also need conduit and weatherproof fittings for cable entry, a compatible Tigo EI inverter and battery, and an active Tigo Energy Intelligence account for cloud monitoring access.

Why choose the Tigo EI ATS 200A with Generator Support (TSS-200-US-G)?

The TSS-200-US-G is the only model in Tigo's ATS lineup that combines a 200A main circuit breaker, generator control, built-in transformer, and energy metering in a single NEMA 4X enclosure — the correct configuration when a site needs full-service-entrance capability, generator integration, and automatic transfer switching without a separate panel. Where the standard 200A model (TSS-200-US) omits generator support, and the 50A model (TSS-50-US) lacks the MCB and metering, this unit is purpose-built for installations that demand maximum backup flexibility and code-compliant service disconnection in one weatherproof assembly.