Overview
The GN22-12 is an indoor high voltage AC disconnector for three-phase 50 Hz switchgear rated 12 kV. It is offered in two high-current groups — 1600 to 2000 A and 2500 to 3150 A — with 4 s short-time withstand up to 50 kA and peak withstand up to 125 kA, and a wall-through (type C) version for panel-wall isolation.
Under voltage but without load it connects, interrupts or transfers circuits and gives a clearly visible insulating break for safe maintenance; it does not break load or short-circuit current, which is cleared by the interlocked circuit breaker. Driven by a manual three-pole mechanism, it suits generator leads, bus sections and large feeders in fixed indoor cubicles.
Model Designation
The type is designated G N 22 -12 C / □ □ and decoded as follows:
- G — disconnector
- N — place of use: indoor
- 22 — design sequence number
- 12 — rated voltage in kV
- C — wall-through type
- □ — rated current in A
- □ — rated short-circuit withstand current in kA
Construction and Operation
- High-current poles. Each pole uses support post insulators and heavy copper knife / contact systems sized for 1600 to 3150 A, mounted on a common steel frame.
- Wall-through option. The C version brings the current conductors through the panel wall so the disconnector can isolate a section on each side of the cubicle.
- Manual operation. The three poles are coupled by a linkage shaft and driven by a manual operating mechanism with open / closed position indication.
- Visible break. Opening the knives gives a clearly visible insulating gap for safe maintenance; it is interlocked with the associated circuit breaker.
Technical Parameters
Rated Parameters
| Item | Unit | 1600 – 2000 A | 2500 – 3150 A |
|---|---|---|---|
| Rated voltage | kV | 12 | 12 |
| Rated frequency | Hz | 50 | 50 |
| Rated current | A | 1600 – 2000 | 2500 – 3150 |
| Rated short-time withstand current | kA | 40 | 50 |
| Rated peak withstand current | kA | 100 | 125 |
| Rated short-circuit duration | s | 4 | 4 |
Rated Insulation Level
| Item | Unit | Between poles / pole-to-earth | Across the break |
|---|---|---|---|
| 1 min power-frequency withstand voltage | kV | 42 | 49 |
| Lightning impulse withstand voltage (peak) | kV | 75 | 85 |
Normal Service Conditions
- Altitude: up to 1000 m
- Ambient temperature: not above +40℃ and not below −25℃
- Relative humidity: daily average not above 95%, monthly average not above 90%
- Water-vapour pressure: daily average not above 2.2 × 10⁻³ MPa, monthly average not above 1.8 × 10⁻³ MPa
- Site: free from fire, explosion, corrosion of metals, harmful gases that damage insulation and conductive dust
Installation & Wiring
Installation and Mounting
Mount the poles on the common steel frame inside the cubicle at the specified phase spacing, fix the frame through the 4 × 18 × 28 mm mounting holes, and for the C version pass the wall-through bushings through the panel opening. Couple the poles to the operating mechanism, then verify free travel, correct contact seating and the full visible break before energising, and bond the frame to the earth network.
Outline & Mounting Dimensions
| Type designation | A | B | C | D | E |
|---|---|---|---|---|---|
| GN22-12/1600-2000 | 255 | 305 | 527 | 490 | 50 |
| GN22-12/2500-3150 | 262 | 325 | 538 | 494 | 60 |
| GN22-12C/1600-2000 | 537 | 255 | 305 | 807 | 580 |
| GN22-12C/2500-3150 | 539 | 267.5 | 330 | 880 | 630 |
All dimensions in mm and correspond to the outline drawing; mounting holes 4 × 18 × 28 mm.
Selection & FAQs
Selection Guide
- Choose the rated-current group (1600–2000 A or 2500–3150 A) to match the feeder or generator lead; short-time and peak withstand rise with current.
- Select the standard indoor type or the wall-through C type according to the cubicle layout.
- Confirm the mechanism position and interlock against the associated circuit breaker.
Frequently Asked Questions
Q1: What does the type designation GN22-12C mean?
G is the disconnector, N the indoor place of use and 22 the design sequence number; 12 is the rated voltage in kV and C denotes the wall-through type. The trailing figures give the rated current in A and the rated short-circuit withstand current in kA.
Q2: Can the GN22-12 break load or short-circuit current?
No. It connects, interrupts or transfers circuits under voltage but without load and provides a visible isolating gap; load and fault currents are handled by the associated circuit breaker.
Q3: What current ratings are covered?
Two groups: 1600 to 2000 A (40 kA short-time / 100 kA peak) and 2500 to 3150 A (50 kA short-time / 125 kA peak), for 4 s short-circuit duration.
Q4: What is the insulation level?
1 min power-frequency withstand 42 kV between poles and pole-to-earth and 49 kV across the break; lightning impulse withstand 75 kV and 85 kV across the break (peak).
Q5: What is the wall-through (C) version?
The C type brings the conductors through the panel wall so the disconnector can isolate a section on each side of the cubicle; its frame is deeper (dimensions A / D / E are larger) than the standard type.
Q6: What are the service conditions?
Altitude up to 1000 m, ambient −25℃ to +40℃, relative humidity daily up to 95% and monthly up to 90%, and a site free from fire, explosion, corrosive or conductive contamination. See the disconnector range for related models.