GW4 Outdoor Disconnector 40.5kV 1250A | Double-Post Horizontal Rotation High-Voltage Isolator, IEC 129 GB 1985-89

Product Overview

The GW4 is a double-post, horizontal-rotation outdoor AC high-voltage disconnector for three-phase 50 Hz networks rated 12, 17.5 and 40.5 kV. It opens and closes lines under voltage but without load, giving a clearly visible insulating break; it cannot break load or short-circuit current. Two support-post insulators per pole rotate the knife contacts through about 90°. Versions come without earthing, with single-side or double-side earthing (D), and a pollution-proof grade II insulator type suits contaminated sites. The series meets GB 1985-89 and IEC 129 / IEC 694.

Product Display

GW4 Outdoor Double-Post Horizontal-Rotation High-Voltage Disconnector - display

GW4 Outdoor Double-Post Horizontal-Rotation High-Voltage Disconnector - poster_display

Model Designation

GW4 Outdoor Double-Post Horizontal-Rotation High-Voltage Disconnector - model

Model format: G W 4-12/□□

G – disconnector
W – place of use: outdoor
4 – design sequence number
12 – rated voltage, kV
□ – rated current, A
□ – rated short-circuit withstand current, kA

Service Conditions

Altitude: 1000 to 3000 m
Ambient temperature: not above +40 °C and not below -30 °C (-40 °C for cold areas)
Wind pressure: not above 700 Pa (wind speed about 34 m/s)
Seismic intensity: not above intensity 8
Ice thickness: not above 10 mm
Site free from flammable or explosive hazards, chemical corrosion and violent vibration
Insulator pollution level: general type grade 0, pollution-proof type grade II

Construction

Each pole carries two support-post insulators that rotate in opposite directions to open or close the knife contacts through about 90°, giving a wide, clearly visible break. The base frame, support insulators, outgoing terminals and self-cleaning finger contacts form the main conducting circuit.

The disconnector is driven by a manual operating mechanism through the three-phase linkage shaft. It is supplied without earthing, with single-side earthing or as the D type with double-side earthing – where fitted the earthing switch is interlocked against the main contacts – and a pollution-proof insulator option (grade II) is available for heavily polluted areas.

Technical Data

Rated voltage (kV)	Rated current (A)	Rated peak withstand current (kA)	Rated short-time withstand current, 4 s (kA)
12	600 – 630	80	31.5
17.5	400 – 1000	50	20
40.5	400 – 1250	80	31.5
Earthing switch (where fitted)	–	50 / 80	20 / 31.5

Selection note: Choose the rated voltage – 12, 17.5 or 40.5 kV – and the rated current to match the feeder, then select the earthing arrangement: without earthing, single-side earthing or double-side earthing (D). For heavily polluted sites order the pollution-proof type with insulator pollution grade II, and confirm the mechanism position against the gantry layout.

Standards

The GW4 is designed and tested to GB 1985-89 AC High-Voltage Disconnectors, IEC 129 (1984) AC Disconnectors and Earthing Switches and IEC 694 (1980) Common Specifications for High-Voltage Switchgear and Controlgear.

Technical note: The catalogue ratings summarise the series; the applicable values are fixed by the ordered type designation – rated current and rated short-circuit withstand current – and follow the nameplate and the documents shipped with the switchgear. Dimensions are taken from the catalogue outline drawing and are for foundation preparation only; confirm the certified dimensional drawing with the ordered voltage, current and earthing arrangement.

Installation & Dimensions

Installation Diagram

GW4 Outdoor Double-Post Horizontal-Rotation High-Voltage Disconnector - installation

Assemble the double-post poles on the common base frame at the specified phase spacing and fix the frame to the gantry or foundation through the mounting holes – 2 × Φ18 on the GW4-17.5 base at a 283 mm hole pitch. Couple the poles to the manual operating mechanism with the three-phase linkage shaft, verify free travel through about 90°, correct contact seating and the full visible break before energising, and bond the base frame to the earth grid.

Dimension	Value
Mounting holes (GW4-17.5 base)	2 × Φ18
Mounting hole pitch	283 mm
Knife contact rotation	approx. 90°

Safety notice: The GW4 has no load or short-circuit breaking capability: open the associated circuit breaker before operating the disconnector off, and close the circuit breaker only after the disconnector is closed. Keep the earthing-switch interlock against the main contacts operative so the unit cannot be operated under load, and apply earthing only after the isolated section has been proved dead.

FAQs

G is the disconnector, W the outdoor place of use and 4 the design sequence number; 12 is the rated voltage in kV. The final two fields give the rated current in amperes and the rated short-circuit withstand current in kA.

No. It only opens and closes no-load lines under voltage and, with the associated circuit breaker, provides a clearly visible insulating break for safe isolation. Load and fault currents are cleared by the circuit breaker.

The GW4 is supplied without earthing, with single-side earthing, or as the D type with double-side earthing. Where fitted, the earthing switch is interlocked against the main contacts to prevent misoperation.

Rated voltage is 12 / 17.5 / 40.5 kV with rated currents of 600-630 / 400-1000 / 400-1250 A respectively. Peak withstand is 80 / 50 / 80 kA and 4 s short-time withstand 31.5 / 20 / 31.5 kA; the earthing switch, where fitted, rates 50 / 80 kA peak and 20 / 31.5 kA for 4 s.

Altitude 1000 to 3000 m, ambient temperature from -30 °C (-40 °C for cold areas) up to +40 °C, wind pressure up to 700 Pa (about 34 m/s), seismic intensity up to 8 and ice thickness up to 10 mm. Insulator pollution level is grade 0 for the general type and grade II for the pollution-proof type.

GB 1985-89 for AC high-voltage disconnectors, IEC 129 (1984) for AC disconnectors and earthing switches, and IEC 694 (1980), the common specifications for high-voltage switchgear and controlgear.

GW4 Outdoor Double-Post Horizontal-Rotation High-Voltage Disconnector