Among all switching devices, the disconnect switch is a special case — it cannot break load current, let alone short-circuit current. It sounds like it "can't do anything," yet it is an indispensable maintenance safety device in distribution systems.
Dongfa Intelligent supplies global power engineering buyers with factory-direct disconnect switches. Its core mission is to provide a visible, reliable disconnection point during maintenance, completely isolating the line from the power source and protecting maintenance personnel.
Because its function is so simple, the most common procurement mistake is also more subtle: looking only at rated current while ignoring mounting dimensions; looking only at price while ignoring insulation distance. This article covers selection logic, company capabilities, and real data to help buyers avoid these hidden traps.
We recommend confirming in this order — voltage first, then dimensions, then earthing requirements.
12kV, 24kV, or 40.5kV? Voltage class determines insulation level.
12kV: 42kV / 48kV power-frequency withstand · 24kV: 65kV / 79kV · 40.5kV: 95kV / 115kVThis is the most easily overlooked step. Indoor disconnect switches commonly have phase spacings of 210mm, 230mm, 250mm, 275mm, and also nine specifications from 150mm to 275mm.
Replacement projects especially need attention: existing cabinet mounting hole distances are often non-standard.Disconnect switches with earthing switch (model suffix D) integrate isolation and earthing functions on one base, saving cabinet space and simplifying interlocking design.
If reliable earthing is needed during maintenance, choose the earthing switch version.Dongfa Intelligent's technical team reviews these parameters with you before production. We have handled many replacement projects and understand the importance of dimensional matching — especially when the original cabinet's mounting hole distances are non-standard.
Disconnect switches serve different roles across indoor substations, outdoor distribution lines, retrofit projects, and industrial cabinets.
GN19 and GN30 series mounted in switchgear cabinets, providing visible isolation between the busbar and incoming feeder for safe maintenance.
GN30 series rated up to 3150A with main-circuit resistance as low as 12μΩ, suitable for high-current main transformer incoming cabinets.
GW9 series engineered for wind, sand, salt spray, and high-humidity environments, covering 12kV, 17.5kV, and 24kV outdoor lines.
Non-standard phase spacing and mounting hole distances reworked from customer installation drawings or measurement data, fitting the existing cabinet.
Four representative models across indoor and outdoor applications, from 12kV to 40.5kV.
| Model | GN19-12/630 | GN30-12(D)/3150-50 | GN27-40.5/1250-31.5 | GW9-12/630 |
|---|---|---|---|---|
| Rated Voltage | 12kV | 12kV | 40.5kV | 12kV |
| Rated Current | 630A | 3150A | 1250A | 630A |
| 4s Short-Time Withstand | — | 50kA | 31.5kA | 20kA |
| Main-Circuit Resistance | — | 12μΩ | — | — |
| Phase Spacing | 210 / 230 / 250 / 275mm | 250 / 275mm | — | — |
| Earthing Switch | Optional | Integrated | Optional | — |
| Installation | Indoor | Indoor | Indoor | Outdoor |
Dongfa Intelligent (Zhejiang Dongfa Intelligent Electric Technology Co., Ltd.) was founded in 2012 in Yueqing Economic Development Zone, Wenzhou, Zhejiang — China's high-voltage electrical industrial hub. The factory covers over 2,000㎡, with 17 employees, 4 technical engineers, 2 production lines, and 1 set of testing equipment. Monthly capacity: 600–700 units. Annual capacity: 7,000–8,000 units. Products have been exported to Southeast Asia and parts of Europe.
Disconnect switches are standard products, but those in replacement projects are often "non-standard." Many customers come to us with mounting dimensions from old cabinets, and the original models are long discontinued — standard products won't fit. Our core capability is flexible customization: customizing phase spacing and mounting dimensions based on customer-provided installation drawings or measurement data, ensuring the new disconnect switch fits the existing cabinet. From drawing confirmation to production delivery, our technical team follows up throughout, responding to dimension matching questions within 1 working day and initiating after-sales within 24 hours.
“We had an old substation retrofit project in the Philippines. The existing disconnect switch had a 230mm phase spacing and non-standard mounting hole distance. Several suppliers said they couldn't do it. Dongfa Intelligent's technical team redrew the drawings based on our measurements and delivered in three weeks. It fit perfectly.” — Project Manager, Southeast Asian Power Engineering Company
Please provide: Voltage Class + Rated Current + Mounting Dimensions / Phase Spacing + Earthing Switch (Yes/No) + Quantity. If you have the original disconnect switch model or installation drawings, please include them. Our technical team will confirm compatibility and quote within 24 hours.
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