Honeywell SZR-LY2-N1 110VAC Safety-Enhanced DPDT Relay: Reliable Control for Harsh Industrial Sites
The Honeywell SZR-LY2-N1 110VAC is a ruggedized double-pole double-throw (DPDT) general-purpose relay engineered for demanding industrial control environments where signal integrity, coil stability, and contact reliability are non-negotiable. Designed as part of Honeywell’s proven SZR Series, this relay delivers consistent switching performance across high-load, high-interference, and continuous-duty production scenarios — making it a trusted component in safety-critical control cabinets, interlock circuits, and field automation panels worldwide.
In industrial facilities where control interruptions carry real operational and safety consequences — petrochemical processing units, power generation switchgear, mining extraction systems, water treatment SCADA panels, metallurgical furnace controls, and port logistics automation — the SZR-LY2-N1 provides the switching backbone that keeps relay logic stable under voltage fluctuations, electromagnetic interference, and thermal stress. Its 8-pin octal base format ensures straightforward field replacement without rewiring, minimizing downtime during maintenance windows.
Safety Reliability Table
| Parameter | Specification |
|---|---|
| Model / Full SKU | SZR-LY2-N1 110VAC |
| Brand / Series | Honeywell / SZR Series |
| Contact Configuration | DPDT (Double Pole Double Throw) — 2NO + 2NC |
| Coil Voltage | 110V AC (50/60 Hz) |
| Contact Rated Current | 10A (resistive load) |
| Contact Rated Voltage | 250V AC / 28V DC |
| Mounting Base | 8-Pin Octal Socket (PTF08A compatible) |
| Coil Power Consumption | Approx. 1.6VA (AC) |
| Insulation Resistance | ≥100 MΩ (500V DC) |
| Dielectric Strength | 2,000V AC (coil to contact) |
| Mechanical Life | ≥10,000,000 operations |
| Electrical Life | ≥100,000 operations (rated load) |
| Operating Temperature | -40°C to +70°C |
| Surge / Transient Protection | Coil suppression diode / varistor compatible |
| Vibration Resistance | 10–55 Hz, 1.5mm amplitude |
| Enclosure / Protection | Dust-cover or sealed options available |
| Country of Origin | China (CN) |
| Compliance | CE, RoHS |
| Warranty | 12 Months — Full replacement or refund on verified defects |
| Outgoing Inspection | 100% coil energization and contact continuity tested before shipment |
Control Cabinet Protection Strategy
In a well-engineered industrial control cabinet, the Honeywell SZR-LY2-N1 110VAC relay rarely operates in isolation. It functions as a critical switching node within a layered protection architecture. When mounted on a PTF08A octal relay socket with integrated LED indicator and test button, field technicians can verify relay status without interrupting the control circuit — a key advantage during live-panel diagnostics in continuous production environments.
For coil voltage stability, the SZR-LY2-N1 is typically powered through a Honeywell or equivalent 110VAC control power transformer or a dedicated DIN-rail mounted AC/DC power supply module with surge suppression output. Pairing the relay with a RC snubber circuit or MOV varistor suppressor across the coil terminals significantly reduces inductive kickback, protecting adjacent PLCs, safety controllers, and I/O modules from transient voltage spikes that can cause spurious trips or input card damage.
In interlock and safety relay circuits, the SZR-LY2-N1 is frequently used alongside Honeywell safety relay modules (such as the FF-SRS5924A or equivalent SIL-rated safety relay) to form a redundant switching layer. The DPDT contact configuration allows simultaneous control of two independent circuits — for example, cutting power to a motor drive while simultaneously signaling a Siemens S7-300 or S7-1500 PLC digital input card of the trip event. This dual-channel feedback architecture is essential in SIL 2 interlock loops for emergency shutdown (ESD) systems.
To protect against electromagnetic interference in high-noise environments — such as near variable frequency drives (VFDs), large contactors, or welding equipment — the relay panel should incorporate shielded control cable, proper grounding bars, and DIN-rail mounted EMI filters. When the SZR-LY2-N1 is used in proximity to Schneider Electric Modicon M340 or M580 remote I/O racks, proper cable segregation between power and signal wiring prevents signal drift and false triggering on relay coil inputs.
For applications requiring time-delayed switching — such as motor star-delta transition control or pump sequencing — the SZR-LY2-N1 can be paired with a DIN-rail timer relay module (on-delay or off-delay type) to create a low-cost, reliable timing circuit without requiring PLC programming changes. In power distribution panels, upstream miniature circuit breakers (MCBs) and surge protective devices (SPDs) safeguard the relay coil circuit from line transients and short-circuit faults, ensuring the SZR-LY2-N1 operates within its rated electrical envelope throughout its service life.
Critical Industrial Safety Applications
Petrochemical & Refinery Plants: In hazardous area control panels and ESD systems, the SZR-LY2-N1 serves as an isolation relay between field instruments and safety PLCs. Its robust contact ratings handle the switching of solenoid valve coils and alarm annunciator circuits in Zone 2 classified areas (when installed in appropriate Ex-rated enclosures), ensuring process shutdown commands are executed reliably even under high ambient temperature and corrosive atmosphere conditions.
Power Generation & Substation Automation: In generator protection relay panels and substation SCADA systems, the SZR-LY2-N1 provides auxiliary contact multiplication for protection relay outputs. It interfaces between numerical protection relays and circuit breaker trip coils, ensuring that trip signals are faithfully transmitted without contact bounce or signal degradation — critical for grid stability and equipment protection.
Mining & Mineral Processing: Underground and surface mining operations subject control equipment to extreme vibration, dust ingress, and wide temperature swings. The SZR-LY2-N1’s mechanical robustness and sealed contact chamber make it suitable for conveyor belt interlock panels, crusher motor control centers, and ventilation fan safety circuits where relay failure could result in personnel hazard or production loss.
Water & Wastewater Treatment: In pump station control panels and SCADA-linked RTU cabinets, the SZR-LY2-N1 switches pump motor contactors, valve actuators, and alarm outputs. Its resistance to humidity and condensation — when properly enclosed — ensures reliable operation in wet utility environments where control panel integrity directly affects public water supply safety.
Metallurgy & Steel Manufacturing: Continuous casting lines, rolling mill drives, and furnace temperature control systems demand relays that maintain contact integrity under high-frequency switching cycles and elevated ambient temperatures. The SZR-LY2-N1’s rated electrical life of 100,000 operations at full load supports long maintenance intervals in these high-cycle applications.
Port & Logistics Automation: Container crane control systems, automated guided vehicle (AGV) charging panels, and conveyor interlock circuits in port terminals rely on general-purpose relays for signal routing and safety interlock functions. The SZR-LY2-N1’s compact DIN-rail-compatible footprint (via octal socket) and standard 8-pin pinout simplify panel layout and spare parts management across large fleets of control cabinets.
Safety and Quality FAQ
Q1: What warranty coverage is provided for the Honeywell SZR-LY2-N1 110VAC?
All units are covered by a 12-month warranty from the date of shipment. If a unit fails under normal operating conditions within the warranty period, we provide a full replacement or refund upon verification. Warranty claims are processed promptly with no unnecessary delays.
Q2: How is each unit tested before shipment?
Every SZR-LY2-N1 undergoes 100% outgoing inspection prior to dispatch. Testing includes coil energization at rated voltage (110VAC), contact continuity verification across all NO and NC contacts, and insulation resistance spot-check. Units that do not meet specification are quarantined and not shipped.
Q3: Is the SZR-LY2-N1 compatible with standard octal relay sockets and existing Honeywell SZR-series installations?
Yes. The SZR-LY2-N1 uses the industry-standard 8-pin octal base, compatible with PTF08A and equivalent sockets from multiple manufacturers. It is a direct form-fit-function replacement for existing SZR-series DPDT relays in Honeywell and third-party control panels, requiring no wiring modifications.
Q4: Can long-term supply be guaranteed for ongoing maintenance and spare parts programs?
We maintain dedicated stock of the SZR-LY2-N1 110VAC to support ongoing MRO (maintenance, repair, and operations) programs. Customers with recurring demand can arrange scheduled delivery agreements to ensure uninterrupted spare parts availability. Contact our sales team to discuss volume pricing and supply continuity arrangements.
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