Schneider Electric LV431540 – Compact NSX Undervoltage Release (MN) for Safe, Remote Tripping

The Schneider Electric LV431540 is an internal MN undervoltage release for Compact NSX molded case circuit breakers, typically used on NSX100/160/250 frames. From my experience, teams use it to force an automatic, fail-safe trip when the control supply drops or is intentionally removed—ideal for emergency-stop chains, interlocks, and remote shutdowns. You might notice that it installs inside the breaker, so there’s no extra panel footprint, and wiring is straightforward on the A1–A2 terminals.

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Key Features

• Fail-safe tripping – When the control voltage falls below a threshold, the MN release trips the breaker automatically, protecting equipment and personnel.
• Internal, panel-neutral installation – Mounts inside the Compact NSX breaker; no additional door cut-outs or external space required.
• Direct A1–A2 wiring – Simple 2-wire coil control; suits interlocks, safety relays, PLC interposed outputs, and building management signals.
• Compatible with Compact NSX – Designed for NSX100/160/250 frames in most cases, keeping your accessory strategy consistent across panel designs.
• Reliable operation – Built to IEC 60947-2 accessory standards; typically stable under industrial vibration and temperature ranges.
• Maintenance-friendly – Easy to test by removing the control supply; no complex calibration required.

Technical Specifications

Application Fields

Typical applications include MCC panels, motor feeders, UPS input/output breakers, genset changeover boards, data center distribution, and building safety systems. A common setup is wiring the MN release through an E‑stop loop or fire alarm interface; when the loop drops out, the breaker trips immediately. One maintenance manager told us they adopted it on chiller feeders so loss of chilled water alarm cuts power safely before equipment damage occurs.

Advantages & Value

• Reliability – Factory‑matched to Compact NSX; fewer surprises during commissioning and audits.
• Safety compliance – Supports interlocking requirements for machinery and building systems that demand undervoltage trip behavior.
• Compatibility – Works with widely used NSX frames, helping standardize spare parts across sites.
• Cost control – Internal mounting cuts panel hardware and door cut‑out time; in many cases, no extra din accessories are needed.
• Technical support – Clear wiring, testable behavior, and broad field familiarity reduce troubleshooting time.

Installation & Maintenance

• Panel environment – Install in a closed, ventilated switchboard per IEC standards; maintain adequate spacing for breaker heat dissipation.
• Wiring – Connect the control supply to A1–A2. Use ferrules and tighten to the torque specified for the accessory terminals. Keep control wiring segregated from power conductors.
• Protection and testing – Provide upstream protection for the control circuit. Verify trip function by removing the MN control voltage during FAT/SAT.
• Safety – De‑energize and lock out the breaker before installing the module. Only certified personnel should access internal accessories.
• Routine checks – Periodically test the undervoltage trip in line with site procedures. Inspect terminals for loosening and dust; re‑torque if required.

Quality & Certifications

• CE marking; RoHS compliant
• Designed to operate within IEC 60947-2 frameworks when installed in Compact NSX
• Manufacturer warranty aligns with Schneider Electric’s policy; our supply warranty: 365 days