GND5-12 Indoor Disconnector 12kV 25kA | High-Voltage Switchgear Equipment for Power Systems | IEC Certified

Product Overview

The GND5-12 is an indoor rotary-type high-voltage AC disconnector with single-sided earthing for three-phase 50 Hz systems rated 12 kV. Under voltage but without load it isolates lines, prevents mal-operation and earths the de-energised circuit, giving reliable separation from the main bus when a circuit breaker or other component is serviced. The rotating knife and the built-in earth contacts combine isolation and protective earthing in one compact frame for metal-enclosed switchgear, offered in 630 A and 1250 A grades with 210 mm rated phase spacing.

Product Display

GND5-12 Indoor Single-Sided Earthing Rotary High-Voltage Disconnector - display

GND5-12 Indoor Single-Sided Earthing Rotary High-Voltage Disconnector - poster_display

Model Designation

GND5-12 Indoor Single-Sided Earthing Rotary High-Voltage Disconnector - model

Model format: G N D 5 – 12 / □

G – disconnector
N – place of use: indoor
D – single-sided earthing
5 – design sequence number
12 – rated voltage, kV
□ – rated current, A (630 / 1250)

Service Conditions

Ambient temperature: upper limit +40 °C, lower limit -15 °C
Altitude: not above 1000 m; for higher altitude the rated insulation level is raised accordingly
Seismic intensity: not above 8 degrees
Relative humidity: daily average not above 95%, monthly average not above 90%
Site free from fire, explosion hazard, severe pollution, chemical corrosion and severe vibration

Construction

Each pole uses a rotating contact system on support and live-part insulators, so the knives make a clear visible break within a compact indoor envelope. Built-in single-sided earth contacts, the D feature, allow the isolated side to be earthed for maintenance safety.

Operation is by a manual mechanism interlocked with the associated circuit breaker; the switch cannot break load or short-circuit current. It provides reliable separation from the main circuit when a circuit breaker or other component is serviced, protecting operating personnel.

Technical Data

Item	Unit	GND5-12/630	GND5-12/1250
Rated voltage	kV	12	12
Rated frequency	Hz	50	50
Rated current	A	630	1250
Rated phase spacing	mm	210	210
4 s rated short-time withstand current	kA	25	31.5
Rated peak withstand current	kA	63	80

Selection note: Choose the rated current first, 630 A or 1250 A; the 4 s short-time and peak withstand currents rise with the current grade (25 kA / 63 kA and 31.5 kA / 80 kA). The D single-sided earthing feature provides maintenance earthing of the isolated side, and the mechanism position and interlock must be confirmed against the associated circuit breaker.

Standards

The source datasheet quotes no specific product standard for the GND5-12; the rated electrical data are taken from the type datasheet. The disconnector is supplied to the manufacturer’s works specification and the agreed technical requirements, with the single-sided earthing contacts and interlock checked before commissioning.

Technical note: Confirm the certified values for the ordered current grade before use, and the certified dimensional drawing for the ordered GND5-12/630 or GND5-12/1250 arrangement before installation. For altitudes above 1000 m the rated insulation level is raised accordingly by agreement.

Installation & Dimensions

Installation Diagram

GND5-12 Indoor Single-Sided Earthing Rotary High-Voltage Disconnector - installation

Fix the disconnector frame to the cubicle mounting plane at the 210 mm rated phase spacing through the four Ø 13 mounting holes, keeping the rotating knives and the single-sided earth contacts clear of obstructions. Couple the poles to the manual operating mechanism, then verify free travel and full seating of the main and earth contacts, the complete visible break, and bonding of the frame to the earth network before energising.

Dimension	Value (mm)
Rated phase spacing	210
Overall width	730
Overall height	490
Frame height	465
Base section (end / pole / end)	80 – 210 – 210 – 210 – 80
Side view (width x height)	440 x 160
Top view depth	250
Mounting holes	4 x Ø 13
Min. cable bend radius	> R150

Safety notice: The GND5-12 has no load or short-circuit breaking capability: the associated circuit breaker must be open before the knives are operated, the interlock must never be bypassed, and the single-sided earth contacts may be closed only after the circuit has been isolated and proved de-energised. Work must be carried out by qualified personnel with the frame bonded to the earth network.

FAQs

G is the disconnector, N the indoor place of use and D the single-sided earthing; 5 is the design sequence number and 12 the rated voltage in kV. The figure after the slash gives the rated current in amperes, 630 A or 1250 A.

Under voltage but without load it isolates lines, prevents mal-operation and earths the de-energised circuit. This gives reliable separation from the main circuit while a circuit breaker or other component is being serviced.

Two grades are offered: 630 A with 25 kA short-time withstand for 4 s and 63 kA peak withstand, and 1250 A with 31.5 kA and 80 kA respectively.

No. It switches circuits under voltage but without load and provides a visible isolating gap; load and fault currents are handled by the associated circuit breaker.

The 1 min power-frequency withstand voltage is 42 kV between poles and pole-to-earth and 48 kV across the break; the lightning impulse withstand voltage (peak) is 75 kV and 85 kV across the break.

In 12 kV three-phase 50 Hz indoor systems, as part of metal-enclosed switchgear or as an isolating and earthing section. Above 1000 m altitude the rated insulation level is raised accordingly.

GND5-12 Indoor Single-Sided Earthing Rotary High-Voltage Disconnector