Dependable Automatic Backup Power for 120/240V Three-Phase Systems
The RTSN800J3 is a high-capacity 800 Amp Automatic Transfer Switch (ATS) engineered to provide seamless power source switching between utility and generator feeds. Specifically configured for 120/240 Volt, 3-Phase (3P) applications, this unit is ideal for facilities requiring stable backup power for mixed single-phase and three-phase loads, including lighting, HVAC, and light industrial equipment.
Key Specifications:
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Amperage: 800 Amps
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Voltage: 120/240 Volts, 3-Phase (3P), 3-Wire + Neutral + Ground (Delta configuration typical for 120/240 3P)
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Enclosure Type: NEMA 3R (Rainproof, sleet-resistant – suitable for outdoor installation)
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Rating: Non-Service Rated (Requires upstream overcurrent protection; no built-in main breaker)
Core Features:
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Automatic Source Monitoring: The microprocessor controller continuously monitors utility source voltage and frequency. Upon utility failure, it signals the generator to start, transfers the load to emergency power, and automatically retransfers back to utility when normal power is restored, followed by an engine cooldown cycle.
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120/240V 3-Phase Configuration: Specifically designed for less common 240V delta three-phase systems (often a "high leg" or "wild leg" delta). Supports both three-phase motor loads and single-phase 120V lighting/receptacle loads from the same transfer switch.
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NEMA 3R Outdoor Enclosure: Constructed from heavy-gauge galvanized steel with a corrosion-resistant finish. Protects against rain, snow, and sleet, allowing for safe outdoor pad or wall mounting without requiring a separate building.
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Non-Service Rated Design: Offers a compact footprint and lower cost compared to service-rated versions. Must be installed downstream of a fused disconnect or circuit breaker that provides overcurrent and short-circuit protection.
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High Withstand & Close-On Ratings: Engineered to coordinate with upstream protective devices, allowing the switch to withstand fault currents without damage when properly protected.
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Electrically Operated / Mechanically Held: Eliminates coil heating and ensures positive contact retention with low power consumption.
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User-Friendly Controller: Provides LED status indicators, push-button testing, programmable generator exercise timer, and event history logs.
Typical Applications:
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Small commercial buildings with 120/240V 3-phase delta service
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Rural industrial shops and farm operations
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RV parks and marinas with mixed 120V single-phase and 240V 3-phase equipment
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Telecommunications shelters
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Small water treatment facilities
