FZN21-40.5 Indoor Load Break Switch | 33kV Medium Voltage Switch

🔹 Product Overview

The FZN21-40.5 indoor load break switch is engineered for 33kV medium-voltage distribution systems, delivering secure load switching, isolation, and grounding. With a rated voltage of 40.5kV, it is perfectly suited for use in switchgear cabinets and RMUs (Ring Main Units) across substations, industrial plants, and utility grids.

Thanks to its compact gas-insulated design and three-position operation (ON / OFF / EARTH), the FZN21 ensures arc safety, low maintenance, and long-term operational reliability.

⚙️ Key Features

• Rated for 33kV distribution systems (40.5kV insulation class)

• SF6 gas-insulated for stable arc interruption

• Manual or motorized spring mechanism

• 3-position: ON / OFF / EARTH

• Factory-filled SF6 gas, sealed enclosure

• Maintenance-free operation for up to 10 years

• Suitable for indoor switchgear cabinets (KYN61, XGN15)

📐 Technical Specifications

✅ Compliance & Certifications

• GB3804 – High-voltage AC load break switch

• IEC 60265-1 – AC switches for rated voltages above 1kV

• IEC 62271-103 – High-voltage switching devices

• ISO 9001 / ISO 14001 / ISO 45001 certified

• CE conformity & factory test reports available

🔌 Application Scenarios

• 33kV indoor switchgear cabinets in distribution networks

• Utility substations and smart grid feeders

• Medium-voltage RMUs (Ring Main Units)

• Industrial plant supply panels

• Compact transformer protection units with fuse combinations

🌍 Case Study: 33kV Grid Upgrade in Muscat, Oman

In 2022, Oman Electricity Transmission Company deployed 42 FZN21-40.5 load break switches in a 33kV substation expansion across Muscat’s industrial zone. The project aimed to stabilize feeder performance and reduce fault repair time.

✅ Result:

• 100% SF6 gas sealing success in the first year

• 10,000+ operations without mechanical failure

• Integrated into Siemens 8DJH RMUs

(Source: OEM Technical Report, 2023 – Muscat Grid Modernization Plan)

❓ Frequently Asked Questions (FAQ)

1. What’s the rated voltage vs. system voltage?
FZN21-40.5 is rated for 40.5kV but is commonly applied in 33kV networks for insulation margin.

2. Does it support automatic motor operation?
Yes. It can be equipped with a motorized spring mechanism for remote control.

3. Can it be combined with a fuse unit?
Yes. For transformer protection, we offer the FZRN21 variant with HRC fuse integration.

4. Is SF6 gas pre-filled?
Yes. Every unit is factory-sealed and tested before shipping.

5. What’s the delivery time for bulk orders?
Typically 15–25 working days, depending on quantity and customization.

📞 Contact Us for Technical Support or Quotation

Need help selecting the right load break switch for your 33kV system? Our engineers are ready to assist you with drawings, specifications, or project matching.

• Thor, Electrical Engineer

• Wei Shoe Elec Co., Ltd

• 📞 Tel: +86-0577-62788197

• 📱 WhatsApp: +86 159 5777 0984

• 📧 Email: thor@weishoelec.com