100A 4-Pole Automatic Transfer Switch (ATS) with Switched Neutral

Modern critical facilities—from surgical centers and data halls to precision manufacturing plants—increasingly depend on sophisticated 3-phase power systems where the neutral conductor is not merely a return path but an active circuit carrying imbalance currents and serving sensitive single-phase electronics. Our 100A 4-Pole Automatic Transfer Switch is engineered specifically for these demanding applications. It provides complete, automatic source transfer for all three phase conductors plus the neutral, ensuring that when switching between utility and generator power, no part of the electrical system remains interconnected. This eliminates dangerous neutral-to-ground potential differences that can damage sensitive equipment and is the definitive solution for protecting today’s mixed 3-phase and single-phase critical loads.

Core Engineering Advantages

1. True 4-Pole Isolation for System Integrity
Feature: An advanced switching mechanism independently controls L1, L2, L3, and the neutral conductor via a single, microprocessor-driven actuator. The neutral is switched with the same timing and reliability as the phase conductors.
Benefit: Guarantees complete galvanic isolation between power sources. This prevents neutral current summation from creating hazardous voltage differentials between system grounds—a critical protection for medical IT systems, server farms, and laboratories where even minor ground loops can cause data corruption or equipment failure.

2. Intelligent Neutral Management
Feature: Sophisticated control logic provides configurable neutral switching options, including “solid neutral” (for separately derived systems) or “switched neutral” configurations, with full monitoring of neutral conductor status.
Benefit: Ensures proper grounding and bonding per NEC Article 250 and IEC 60364 requirements. Protects against neutral conductor faults and provides compatibility with both separately derived and non-separately derived backup power systems.

3. Advanced Power Quality Monitoring
Feature: The digital controller performs continuous vector analysis on all three phases plus neutral-to-ground voltages, detecting faults including phase loss, severe imbalance, harmonics distortion (>10% THD), and neutral degradation.
Benefit: Prevents transfer onto unstable or distorted power, protecting both the ATS and downstream equipment from power quality issues that can be as damaging as complete outages.

4. Professional-Grade Switching Mechanism
Feature: Utilizes a heavy-duty, four-pole contactor or molded case circuit breaker with motorized operator, specifically designed for the higher electrical stress of switching neutral under load imbalance conditions.
Benefit: Provides reliable performance even when transferring systems with significant single-phase load imbalance. The mechanism is rated for 100,000 mechanical operations with maintenance intervals exceeding 5 years under normal use.

Technical Specifications

Parameter	Specification
Type	Automatic Transfer Switch (Open Transition)
Poles	4 (3 Phase + Switched Neutral)
Rated Current	100A per Pole Continuous
Voltage Rating	480Y/277V or 208Y/120V AC, 3-Phase, 4-Wire
Short-Time Withstand	35kA RMS Symmetrical for 3 Cycles
Transfer Time	< 100ms (After Source Stable)
Neutral Rating	100% Rated (Equal to Phase Conductors)
Controller	Programmable Microprocessor with Touch Interface
Communication	Dual RS485 Ports (Modbus RTU & BACnet MS/TP)
Enclosure	NEMA 3R (Stainless Steel Hardware)
Standards	UL 1008, IEC 60947-6-1, IEEE 446

Application Scenarios

• Healthcare Critical Areas: Operating rooms, ICU power panels, medical imaging suites (CT/MRI)
• Tier III/IV Data Centers: 3-phase rack PDUs, cooling system controls, server room lighting
• Broadcast & Media Facilities: Production control rooms, transmitter sites, editing suites
• Pharmaceutical Manufacturing: Cleanroom environmental controls, filling line equipment
• Financial Trading Floors: Server cabinets, display systems, communications infrastructure

Value Proposition

1. Eliminate Single Points of Failure
By managing the neutral as critically as the phase conductors, our 4-pole ATS removes the most common design oversight in 3-phase backup systems—neutral interconnection—which can create hidden failure modes even during successful phase transfer.

2. Future-Proof Infrastructure Design
Supports the growing prevalence of non-linear single-phase loads (LED drivers, server power supplies, medical devices) in 3-phase systems without compromising safety or performance.

3. Simplified Regulatory Compliance
Pre-engineered to meet the most stringent requirements of NEC Articles 517 (Healthcare Facilities), 645 (Data Centers), and 708 (Critical Operations Power Systems).

Installation & Service Notes

Professional Installation Required: This device must be installed by qualified personnel familiar with 3-phase, 4-wire system design and local grounding requirements. Neutral grounding configuration must be verified before energization.

Maintenance Protocol: Includes self-diagnostic routines with predictive maintenance alerts. Recommended annual operational testing under simulated outage conditions.

Warranty & Support: Backed by a 5-year comprehensive warranty with optional 24/7 technical support and next-business-day component replacement service.