Overview
The String-level Rapid Shutdown (RSD) unit is a hardware safety component integrated directly into solar PV strings. On a trigger signal from the ground initiator or a grid power loss, the device quickly disconnects DC power at the string level within milliseconds.
Technical Specifications
|
Item |
Specification |
|
Maximum System Voltage |
Up to 1500V DC |
|
Continuous Current |
Up to 30A per string |
|
Protection Rating |
IP68 / NEMA 4X |
|
Inverter Compatibility |
SMA / Fronius / Sungrow / Growatt tested |
|
DC Connectors |
Stäubli MC4 / MC4-Evo 2 (pre-installed) |
|
Power Consumption |
< 1.5W per unit |
Key Benefits
Active Thermal Shutdown
Internal sensor triggers automatic shutdown if the enclosure temperature exceeds 85°C, preventing localized thermal runaway.
PLC Signaling Resilience
Integrated hardware filtering mitigates crosstalk and eliminates nuisance tripping on large-scale C&I rooftops with parallel strings, preventing localized communication failures and associated string downtime.
Zero-Volt Default State
Engineered with a normally-open hardware configuration; any loss of control signal or auxiliary power automatically forces an immediate safe shutdown state.
Low-Loss Conduction
Internal contact resistance is limited to <0.5mΩ, limiting maximum string power loss to ≤0.02%.
Microprocessor Switch Control
Sub-10ms response time from signal reception to contact separation under full load, extinguishing DC arcs to protect physical rooftop assets.
Magnetic Latching Relay Architecture
Utilizes bi-stable relays designed for a mechanical and electrical lifespan that matches standard 25-year PV module warranties.
Application Scenarios
Commercial & Industrial (C&I) Rooftops: Installed directly beneath array frames to meet local fire codes and NEC rapid shutdown mandates.
Harsh Environments (Floating & Agriculture): IP68-rated ingress protection and corrosion-resistant enclosures, reducing maintenance overhead in coastal, floating solar, and agricultural installations.
Retrofit & Utility Asset Upgrades: Compatible with legacy 1000V DC and modern 1500V DC systems, eliminating the capital expense of replacing functional legacy inverters during safety code upgrades.
Manufacturing Capacities
Automated OQC Pass Rates: Factory utilizes 100% automated optical inspection (AOI) and full-load function testing, achieving an Outgoing Quality Control pass rate of ≥99.98%.
Capacity & MOQ: Annual manufacturing capacity of 1.1 million units across 4 automated ISO 9001/14001/45001 certified SMT lines. Commercial MOQ starts at 200 units.
Payment Terms: Standard terms at 30% deposit with 70% balance payable against Bill of Lading (L/C and T/T options available, subject to credit approval).
Component Sourcing & OEM: Private labeling, custom lead lengths, and bracket configurations available for orders exceeding 5,000 units. Semiconductors are sourced from STMicroelectronics, Infineon, and Texas Instruments.
15-Year Product Warranty: Backed by international reinsurance structures to guarantee component replacement across the 15-year project lifecycle.
Logistics & Packaging
ISTA-3A Certified Packaging: Units are individually packed in moisture-sealed anti-static bags and shipped in double-wall corrugated export master cartons.
Palletization Specifications: Standardized 1200mm x 800mm Euro-pallets or 48" x 40" US pallets, stacked max 3 layers with plastic corner protectors and heavy stretch wrap.
Commercial Lead Times: Ex-factory dispatch within 14 days for standard inventory; global port delivery (FOB Shanghai/Ningbo, DDP Rotterdam/LA) within 35-45 days.
Customs & HS Coding: Classified under HS Code 8536.50 (Electrical Switches for Voltages ≤ 1000V/1500V) for streamlined customs clearance.
Consolidated Documentation Kits: Every shipment includes packing lists, Certificates of Origin, and component serialization tracking sheets to ensure a clear chain of custody.
Compliance & Certifications
NEC 2020/2023 Article 690.12 Compliance: Discharges controlled conductors to safely under 30 Volts within 30 seconds of initiation inside the 1-foot array boundary.
UL 1741 & CSA C22.2 Certification: Intertek/TÜV SÜD listed for safety compliance regarding distributed energy resource addressable nodes.
SunSpec Protocol Authentication: Fully compliant with SunSpec PLC communication standards, ensuring plug-and-play interoperability with multi-brand commercial inverters.
IEC 60947-3 Low-Voltage Switchgear Standards: Rated for operational safety and isolation performance under continuous DC thermal loads.
CE & UKCA Marking: Certified for immediate deployment across European Union and United Kingdom commercial solar assets.
Third-Party Test Reports: Complete TÜV and UL test sheets available for download to streamline local commercial permitting.
FAQ
Q: Can it retrofit onto existing 1000V systems without inverter replacement?
A: Yes. It supports both 1000V and 1500V DC systems and has been tested with SMA, Fronius, Sungrow, and Growatt inverters, making legacy upgrades cost-effective.
Q: What happens if the PLC signal is lost or the power goes out?
A: The unit defaults to a normally-open (safe) state, meaning it automatically shuts down without any active command. There is no scenario where a signal failure leaves DC voltage live on the string.
Q: Can this retrofit onto our existing 1000V legacy system?
A: Yes. The device supports both 1000V and 1500V DC systems, so you can upgrade to code compliance without replacing functional inverters or rewiring your array.
Q: Has this RSD been deployed in real commercial projects?
A: Yes. Units are installed on C&I rooftops across Europe, Southeast Asia, and North America. Reference project documentation is available upon request under NDA.
Q: What is the real-world power loss per string?
A: Contact resistance is under 0.5mΩ, capping energy loss at ≤0.02% per string - negligible across a 25-year project lifecycle.
Q: How quickly can samples be arranged for evaluation?
A: Engineering samples (5–10 units) ship within 7 days with full test reports included. Contact us with your inverter model and string configuration for a pre-matched sample kit.
Q: Is installation support available for first-time buyers?
A: Yes. We provide wiring diagrams, torque specs, and a commissioning checklist. Video walkthroughs and remote technical support are available for orders over 500 units.
Q: What documentation is included for local permitting?
A: Every shipment includes TÜV and UL test reports, Certificates of Origin, and component serialization sheets - sufficient for NEC 2023 Article 690.12 permit submissions in most jurisdictions.
Q: What is the warranty claim process if a unit fails in the field?
A: Submit a serial number and failure report; replacement units are dispatched within 5 business days. The 15-year warranty is backed by international reinsurance, not just manufacturer commitment.
Q: What's your defect rate, and how is quality controlled?
A: Every unit passes 100% AOI optical inspection and full-load function testing before shipment, with an outgoing quality pass rate of ≥99.98% across ISO 9001-certified production lines.
