Description
1. Unboxing & Physical Snapshot
- Model & Brand: Siemens WL Series Electronic Trip Unit (ETU) Power Circuit Breaker Accessory (Part No. WLETU776)
- Physical Dimensions (Approximate W x H x): 140.0 mm x 165.0 mm x 90.0 mm (5.51 in x 6.50 in x 3.54 in).
- Estimated Shipping Weight: 1.80 kg (3.97 lbs).
- What’s in the Box: Microprocessor-based electronic trip unit module, digital display/keypad interface faceplate, pluggable rear wiring harness connectors, calibration seal, and manufacturer compliance documentation.
2. Product Introduction
Heavy industrial switchgear and high-capacity electrical distribution centers rely on precision electronic trip units to protect expensive busbars, transformers, and feeder circuits from destructive fault currents. This Siemens WL-series trip unit integrates directly into the face of low-voltage power circuit breakers—which is vital for providing accurate time-current trip curves and real-time electrical metering.
The ruggedized composite enclosure shields sensitive internal microprocessors from heavy electromagnetic interference generated within switchgear compartments. Translating current transformer (CT) secondary signals into intelligent tripping commands, this hardware maintains strict circuit protection parameters under heavy operational electrical stress.
3. Core Technical Specifications
| Parameter | Value |
| Device Type | Electronic Trip Unit (ETU) for Power Circuit Breakers |
| Compatible Breaker Frames | Siemens WL Series (WLS / WLH / WLL / WLC frames) |
| Current Rating Compatibility | 200 A to 5000 A adjustable operational ranges |
| Trip Curve Characteristics | Electronic LSI (Long-time, Short-time, Instantaneous protection) |
| Display & Interface | Integrated LCD screen with local keypad navigation |
| Operating Temperature Range | -20 °C to +70 °C (-4 °F to +158 °F ambient threshold) |
| Enclosure Protection Class | IP20 front-panel classification when installed in breaker |
| Auxiliary Communication | Optional metering and communication bus integration capabilities |
4. Global Compliance & Industry Certifications
- Expected Regulatory Approvals: UL 489, UL 1066, CSA C22.2, CE Mark, and ANSI C37.13 switchgear standards.
- Safety & Compliance Impact: Compliance with stringent UL and ANSI standards guarantees that internal isolation barriers and protective logic correctly interrupt high-fault energy paths, protecting switchgear operators and downstream assets from catastrophic arc flash events.
- Verify specific lot certifications with OEM.
5. Long-Term Storage & Asset Preservation Guide
Keep this electronic trip unit sealed inside its original anti-static (ESD) shielding bag to protect sensitive internal microprocessors from electrostatic discharge events. Maintain warehouse storage conditions at a relative humidity level strictly below 60% to prevent micro-oxidation on the rear plug-in terminal pins over extended holding cycles. Store the unit flat on shelving racks, avoiding heavy stacking weights that could crack or warp the polymer display housing.
6. Physical Installation Prerequisites
- Inspect the breaker trip unit compartment to ensure guide rails and secondary disconnect pins are clean and free of particulate debris before module insertion.
- Align the rear multi-pin connectors carefully and push the module home to guarantee positive, low-resistance seating into the breaker internal harness.
- Secure any retaining screws or mechanical locking latches per manufacturer specifications to prevent loosening under high electrodynamic forces during fault interruption.
7. Buyer’s FAQ (Logistics & Compliance Focus)
- Q: What Harmonized System (HS) code applies for international customs clearance on this breaker trip unit?
- A: Industrial circuit breaker parts, electronic trip devices, and switchgear accessories typically classify under HS code 8538.90 or 8536.20. Confirm exact local code accuracy with your trade compliance broker.
- Q: Does this hardware ship pre-programmed with specific ampere pickup settings?
- A: Units typically ship with standard factory default dial settings. Authorized electrical engineers must adjust the long-time, short-time, and instantaneous parameters to match coordination study requirements during commissioning.
- Q: How does the Country of Origin (COO) documentation affect our import compliance audit?
- A: Manufacturing origin records correspond to authorized North American or European production facilities for this heavy distribution series. Check commercial invoice documentation for precise country details.
- Q: Is specialized transit insurance recommended during shipment?
- A: Yes. Because precision electronic trip units contain delicate display screens and microprocessors vulnerable to mechanical shock, comprehensive transit cargo insurance is strongly advised.
- A: Yes. Because precision electronic trip units contain delicate display screens and microprocessors vulnerable to mechanical shock, comprehensive transit cargo insurance is strongly advised.
