GN24-12 Indoor Earthing Switch HV | High-Voltage Switchgear Equipment for Power Systems | IEC Certified

Product Overview

The GN24-12D is an indoor high-voltage disconnector for three-phase AC 50 Hz switchgear in which the main blades and the earthing knife share one common frame, so a single cubicle unit isolates and earths a de-energised circuit. Q full-service types earth the moving or the stationary contact side, with type 1 left-hand and type 2 right-hand operation and an optional live-voltage indicator; SD types earth both sides through two earthing sets worked separately or by one mechanism. Either contact side, or both, may be changed to wall bushings in the C version, for penetration of the cubicle wall.

Product Display

GN24-12D Series Indoor High-Voltage Disconnector with Earthing Switch - display

GN24-12D Series Indoor High-Voltage Disconnector with Earthing Switch - poster_display

Model Designation

GN24-12D Series Indoor High-Voltage Disconnector with Earthing Switch - model

Model format: GN24-12(D)/□□

G – isolating switch (disconnector)
N – indoor
24 – design sequence number
12 – rated voltage, kV
(D) – with earthing switch
First □ – rated current, A
Second □ – rated short-time withstand current, kA
C – wall-bushing version; Q – full-service version; S in GN24-12SD – two earthing sets; type 1 left / type 2 right operation

Service Conditions

Altitude: 1000 m
Ambient air temperature: the catalogue lists this condition without a limiting value; the range follows the ordering technical conditions
Relative humidity: daily average not more than 95%, monthly average not more than 90%
Seismic intensity: not above intensity 8
Installation site free from fire and explosion hazard, severe pollution, chemical corrosion and violent vibration

Construction

The main disconnector and the earthing knife are assembled on one common frame, so a single cubicle assembly provides isolation and then earthing of a de-energised circuit. Type 1 is operated from the left and type 2 from the right; the Q types earth the moving or the stationary contact side, while the SD types earth both sides through two earthing sets worked separately or together by one mechanism.

Either contact side, or both, may be changed to wall bushings to give the C version for penetration through the cubicle wall, and a voltage-presence indicator is available on the Q full-service types. As a disconnector it makes and breaks circuits under voltage but without load and provides the visible break; it has no load or short-circuit breaking capability.

Technical Data

Item	Unit	Value
Rated voltage (type designation)	kV	12
Rated voltage (catalogue description, as printed)	kV	10
Rated current	A	per type designation and ordering technical agreement; frames tabulated for 400 / 630 / 1000 / 1250 A
Rated short-time withstand current	kA	per type designation / technical agreement / nameplate
Rated peak withstand current	kA	per type designation / technical agreement / nameplate
Earthing arrangement	—	D: one earthed contact side; SD: both sides, two earthing sets

Selection note: Choose the earthing arrangement first – one earthed contact side on the standard frame, or both sides on the SD types – then select type 1 or type 2 according to the side from which the mechanism can be operated in the cubicle. Pick the frame tabulated for the current rating of the circuit among the 400 A, 630 A, 1000 A and 1250 A dimensions, order the C wall-bushing version where circuits pass through the panel wall, and specify the Q full-service version with voltage-presence indicator for severe or compact cubicles. The catalogue prints no rated-parameter table, so confirm the rated current and withstand values from the order code and nameplate.

Standards

The catalogue page quotes no specific product standard and carries no rated-parameter table for the series: the rated current, the short-time withstand current and the peak withstand current are fixed by the type designation and the ordering technical agreement, and are given on the nameplate of the delivered switch.

Technical note: The catalogue describes the series as a device of rated voltage 10 kV while the type designation carries the figure 12; both are reproduced as printed and the rating of the delivered switch is the one stated on its nameplate. In the outline-dimension table the model column repeats GN24-12D type I for three rows with different values without stating the difference; the rows are reproduced as printed and the applicable frame must be confirmed from the order code.

Installation & Dimensions

Installation Diagram

GN24-12D Series Indoor High-Voltage Disconnector with Earthing Switch - installation

Bolt the complete frame to the cubicle structure on the 700 mm mounting span through the 700 × 300 mm hole pattern, connect the conductors to the terminals, and couple the mechanism to the main blade shaft and the earthing shaft on the side given by type 1 (left) or type 2 (right). Check the full travel of both knives before energising. Fixed dimensions in mm: mounting span 700, phase spacing 250 + 250, frame dimension 300 and mounting holes 700 × 300; four arrangements are drawn – GN24-12D type I and type II and the corresponding C versions.

Model	A (400/630 A)	B (400/630 A)	C (400/630 A)	D (400/630 A)	A (1000 A)	B (1000 A)	C (1000 A)	D (1000 A)	A (1250 A)	B (1250 A)	C (1250 A)	D (1250 A)	Mounting holes (mm)
GN24-12D I	890	660	450	125	890	690	480	125	890	700	500	125	700 × 300
GN24-12D II	890	660	450	125	890	690	480	125	890	700	500	125
GN24-12D I	890	660	450	240	890	690	480	350	890	700	500	350
GN24-12D II C	890	660	450	240	890	690	480	350	890	700	500	350
GN24-12D I	920	780	450	125	920	790	480	125	920	790	500	125
GN24-12D II C	920	780	450	240	920	790	480	350	920	790	500	350

Safety notice: A disconnector has no load or short-circuit breaking capability: open the circuit breaker before operating the disconnector off, and close the circuit breaker only after the disconnector is closed. The disconnector and the earthing switch must be interlocked, and the earthing knife may be closed only after the circuit has been isolated and proved de-energised.

FAQs

G is the isolating switch and N the indoor place of use; 24 is the design sequence number and 12 the rated voltage in kV, while D indicates that the switch is supplied with an earthing knife. The two fields after the slash give the rated current in A and the rated short-time withstand current in kA.

The D version carries one earthing knife on the moving or the stationary contact side. The SD version carries two earthing sets on the same frame so that both contact sides can be earthed; one set can be operated on its own or both through a single mechanism.

No. It makes and breaks circuits under voltage but without load and provides the visible break for isolation; load and short-circuit currents are interrupted by the associated circuit breaker. The earthing knife may only be closed after the circuit has been isolated and proved de-energised.

Type 1 is operated from the left side of the frame and type 2 from the right side. C marks the wall-bushing version for penetration through the cubicle wall, and Q the full-service version, to which a voltage-presence indicator can be attached on request.

Altitude of 1000 m, relative humidity with a daily average not more than 95% and a monthly average not more than 90%, seismic intensity not above 8, and a site free from fire and explosion hazard, severe pollution, chemical corrosion and violent vibration. The catalogue lists the ambient temperature without a value, so it is fixed by the ordering conditions.

This catalogue page gives no rated-parameter table, so the electrical data are taken from the type designation and the ordering technical agreement and are stated on the nameplate of the delivered switch. The outline dimensions of the frames tabulated for 400 A, 630 A, 1000 A and 1250 A are printed on the page.

GN24-12D Series Indoor High-Voltage Disconnector with Earthing Switch