The GN19-12 is an indoor high-voltage disconnector for three-phase AC 50 Hz power systems of 12 kV and below. Supplied with a CS6-1 manual operating mechanism, it is used to make and break circuits under voltage but without load, and to provide a visible break for the safe isolation of the equipment under inspection or maintenance.
The switch is built as a three-pole assembly on a common frame: porcelain support insulators carry the knife blades and the static contacts with their copper terminals above and below the frame, and the three poles are coupled to one operating shaft so that the complete set is installed, operated and maintained as a single unit. Derived versions of the series cover pollution-proof and high-altitude service and the disconnector can be supplied with a live-display device; the C version is arranged for mounting through the panel wall.
Model Designation
The type is designated G N19-12 C/□□ and decoded as follows:
- G — isolating switch (disconnector)
- N — indoor
- 19 — design sequence number
- 12 — rated voltage, kV
- C — wall-mounted type (omitted for the standard type)
- □ — rated current, A
- □ — rated thermal stable current, kA
Construction and Operation
- Three-pole assembly. The three poles are mounted on one common steel frame with 250 mm phase spacing (250 + 250 mm) and a 700 mm mounting span, giving an overall width of 948 mm for the complete set.
- Live parts and insulation. Each pole carries the knife blade and the static contact on porcelain support insulators, and copper terminals at the top and bottom of the frame take the busbar or cable connections.
- Manual operation. A CS6-1 manual operating mechanism drives the operating shaft across the frame; the side handle gives a positive make and break action, and the blades are clearly visible in the open position.
- Operating clearance. The outline drawing calls for an operating space of not less than 150 mm so that the handle can travel through its full stroke.
- Wall-mounted version. The C type is arranged for mounting through the wall of the cubicle so that the circuits can be brought out on both sides of the panel.
- Four current ratings. Ratings from 400 A to 1250 A provide 4 s thermal stable currents of 12.5 kA to 40 kA and dynamic stability currents of 31.5 kA to 100 kA at 12 kV.
- Derived versions. Pollution-proof and high-altitude versions are available for severe site conditions, and a live-display device can be added to indicate the presence of voltage on the line side.
Technical Parameters
Rated Parameters
Reproduced from the catalogue table of the series.
| Model | Rated
voltage (KV) |
Rated
current (V) |
4 s thermal
stable current (KV) |
Dynamic
stability current (KA) |
|---|---|---|---|---|
| GN19-10C/400-12.5 | 12 | 400 | 12.5 | 31.5 |
| GN19-10C/630-20 | 12 | 630 | 20 | 50 |
| GN19-10C/1000-31.5 | 12 | 1000 | 31.5 | 80 |
| GN19-10C/1250-40 | 12 | 1250 | 40 | 100 |
Normal Service Conditions
- Altitude: not exceeding 1000 m
- Ambient air temperature: −25℃ to +40℃
- Relative humidity of the surrounding environment: daily average value not more than 95%, daily average value not more than 90%
- Seismic intensity: not above intensity 8
- Installation site: free from fire hazard, flammable or explosive substances, severe pollution, chemical corrosion and violent vibration
Installation & Wiring
Installation and Mounting
Fix the complete three-pole set to the switchgear frame through the holes dimensioned C, bolt the busbar or cable conductors to the copper terminals, and couple the CS6-1 manual operating mechanism to the operating shaft. Leave at least 150 mm clear for handle travel, then check that the blades seat fully home and open to the full visible gap before the assembly is energised.
Outline and Installation Dimensions
Fixed dimensions of the three-pole set (mm): overall width 948, phase spacing 250 + 250, mounting span 700, frame height 240 and side depth 196, with an operating space of not less than 150 mm.
The catalogue tabulates two dimension sets for each current rating without indicating which arrangement each set applies to; confirm the applicable set with the ordering technical conditions.
| Model | Set 1 | Set 2 | ||||
|---|---|---|---|---|---|---|
| A (mm) | B (mm) | C (mm) | A (mm) | B (mm) | C (mm) | |
| GN19-12/400 | 450 | 436 | 4 × 14 × 24 | 420 | 625 | 4 × 18 × 24 |
| GN19-12/630 | 490 | 436 | 4 × 14 × 24 | 4460 | 625 | 4 × 18 × 24 |
| GN19-12/1000 | 510 | 530 | 4 × 18 × 28 | 505 | 745 | 4 × 18 × 28 |
| GN19-12/1250 | 510 | 530 | 4 × 18 × 28 | 505 | 745 | 4 × 18 × 28 |
Applications
- Isolation of indoor switchgear of 12 kV and below during inspection and maintenance
- No-load switching of feeders and busbar sections in distribution and industrial substations
- Isolating switch associated with circuit breakers, contactors and transformers in metal-enclosed cubicles
- Wall-mounted C version for installation through the panel or cubicle wall
- Pollution-proof and high-altitude versions for severe site conditions
Selection & FAQs
Selection Guide
- Match the rated voltage of 12 kV and the frequency of the network to the installation.
- Select the rated current from the four tabulated steps and verify the thermal and dynamic stability values.
- Choose the standard three-pole set or the wall-mounted C version for the cubicle arrangement.
- Order the pollution-proof or high-altitude version where the service conditions are outside the standard range.
- Specify the live-display device and the CS6-1 mechanism position at the time of enquiry.
Frequently Asked Questions
Q1: What does the type designation GN19-12 C/□□ mean?
G is the isolating switch and N the indoor place of use; 19 is the design sequence number and 12 the rated voltage in kV. C marks the wall-mounted type, and the two following fields give the rated current in A and the rated thermal stable current in kA.
Q2: Can this disconnector interrupt load or short-circuit current?
No. It makes and breaks circuits under voltage but without load, and provides a visible break for isolation. Load and short-circuit currents are interrupted by the associated circuit breaker, with which the disconnector must be interlocked so that it cannot be operated under load.
Q3: Which ratings are available in the series?
Four ratings at 12 kV cover 400, 630, 1000 and 1250 A. The 4 s thermal stable current ranges from 12.5 kA to 40 kA and the dynamic stability current from 31.5 kA to 100 kA, as tabulated for each type designation.
Q4: What is the wall-mounted C version used for?
It is the same three-pole disconnector arranged for mounting through the wall of the cubicle, so that the circuits can be brought out on both sides of the panel. For the panel-mounted type with its own bushing arrangement, see our GN19-12 panel disconnector.
Q5: What are the service conditions?
Altitude not exceeding 1000 m, ambient air temperature from −25℃ to +40℃, relative humidity with a daily average value not more than 95% and not more than 90%, seismic intensity not above 8, and a site free from fire hazard, explosive or corrosive substances and violent vibration.
Q6: Which derived versions and accessories can be ordered?
The series is also made in pollution-proof and high-altitude specification, and a live-display device can be added to indicate the presence of voltage. When ordering, state the type designation, the rated current, the thermal stable current, the standard or wall-mounted C version and the mechanism arrangement; see the whole disconnector range for outdoor types.