JN22-40.5 Indoor Earthing Switch for KYN61-40.5 | 40.5kV 31.5kA HV Grounding Switch

Product Overview

The JN22-40.5/31.5 is an indoor high-voltage earthing switch for 40.5 kV, 50 Hz three-phase systems, matched with KYN61-405 and other metal-enclosed switchgear as the protective earthing element during inspection and maintenance. Once the feeder is isolated and proved dead, its three earth knives bond the circuit to earth, and the mechanism interlocks with the switchgear or cubicle door so the knives cannot close onto a live circuit. The compact assembly carries 31.5 kA for 4 s, makes 80 kA peak short-circuit current, and offers five phase-centre distances from 280 to 400 mm.

Product Display

JN22-40.5 Indoor High-Voltage Earthing Switch for KYN61-40.5 - display

JN22-40.5 Indoor High-Voltage Earthing Switch for KYN61-40.5 - poster_display

Model Designation

JN22-40.5 Indoor High-Voltage Earthing Switch for KYN61-40.5 - model

Model format: JN 22 – 40.5 / 31.5 – □

JN – indoor earthing switch
22 – design number
40.5 – maximum voltage, kV
31.5 – 4 s thermal-stability (short-time withstand) current, kA
□ – phase-center distance, mm
Example: JN22-40.5/31.5-300 is the 31.5 kA type with 300 mm phase centres

Service Conditions

Altitude: not above 1000 m
Ambient temperature: upper limit +40 °C, lower limit -25 °C
Seismic intensity: not above 8 degrees
Installed in locations free from fire, explosion hazard, severe dust, chemical corrosion and violent vibration

Construction

The three earth knives are carried on support insulators above a common frame and are driven through a transmission shaft by the operating mechanism, so all three poles make or break the earth connection together. The knives engage static contacts sized to close reliably onto a short-circuit current, and the compact three-pole assembly mounts inside 40.5 kV metal-enclosed switchgear.

The mechanism can be interlocked with the associated switchgear or cubicle door to prevent mal-operation, so the earth connection is made only on an isolated, dead circuit. Where the phase-centre distance is below 360 mm an insulation board is added between the phases, and the frame is bonded to the earth network to complete the protective path.

Technical Data

Item	Unit	Data
Rated voltage	kV	40.5
Rated frequency	Hz	50
Rated short-time withstand current	kA	31.5
Rated short-circuit duration	s	4
Rated peak withstand current	kA	80
Rated short-circuit making current	kA	80
Phase-center distance	mm	280 / 300 / 350 / 360 / 400
1 min power-frequency withstand voltage (phase to earth and phase to phase)	kV	95
Lightning impulse withstand voltage (phase to earth and phase to phase)	kV	185

Selection note: Verify first that the prospective fault current at the installation point stays within the 31.5 kA 4 s short-time and 80 kA peak ratings, then select the phase-centre distance, 280, 300, 350, 360 or 400 mm, to match the cubicle busbar layout; below 360 mm an inter-phase insulation board is fitted. State the full model, rated voltage, short-time withstand current, phase-centre distance and any accessory or interlock requirement when ordering; special requirements are settled between user and manufacturer.

Standards

The source datasheet for the JN22-40.5 names no specific product standard; the rated values are taken from the type datasheet, and ratings and any special service condition follow the order technical agreement and the nameplate of the delivered switch. The switch is supplied as an integral three-pole assembly matched with KYN61-405 and comparable 40.5 kV metal-enclosed switchgear.

Technical note: Values are taken from the type datasheet and the catalogue outline drawing; the certified dimensional drawing for the ordered phase-centre distance governs installation, and where a value is fixed by the order the technical agreement and the nameplate of the delivered switch prevail.

Installation & Dimensions

Installation Diagram

JN22-40.5 Indoor High-Voltage Earthing Switch for KYN61-40.5 - installation

Fix the earthing-switch frame to the cubicle mounting plane through the mounting holes at the selected phase-centre distance, keeping the earth knives and static contacts clear of obstructions. Couple the three poles to the operating mechanism through the transmission shaft, then verify simultaneous and full contact seating of all three poles, correct interlock action and bonding of the frame to the earth network before energising. The catalogue dimensions are for cubicle preparation only; confirm the certified dimensional drawing for the ordered phase-centre distance before installation.

Model	E (mm)	G (mm)	L (mm)	D (mm)
JN22-40.5/31.5-280	280	290	1010	656
JN22-40.5/31.5-300	300	340	1100	696
JN22-40.5/31.5-350	350	340	1200	796
JN22-40.5/31.5-360	360	320	1200	816
JN22-40.5/31.5-400	400	340	1300	896

Safety notice: The JN22-40.5 may only be closed onto a circuit that has been isolated and proved de-energised; it is interlocked with the associated disconnector and circuit breaker so that it cannot be closed onto a live circuit nor opened while the circuit is earthed. It carries short-time fault current and makes short-circuit current, but it breaks no load current, and only qualified personnel may install or operate it.

FAQs

JN identifies an indoor earthing switch and 22 is the design number; 40.5 gives the maximum voltage in kV and 31.5 the 4 s short-time withstand current in kA. The trailing figure after the second dash states the phase-centre distance in millimetres.

It provides protective earthing during equipment inspection and maintenance in 40.5 kV, 50 Hz indoor systems, matched with KYN61-405 and other high-voltage metal-enclosed switchgear. After isolation it bonds the de-energised circuit to earth for personnel safety.

Rated voltage 40.5 kV at 50 Hz, rated short-time withstand current 31.5 kA for 4 s, and both rated peak withstand and short-circuit making current of 80 kA. The switch carries fault current but breaks no load current.

The 1 min power-frequency withstand voltage is 95 kV and the lightning impulse withstand voltage is 185 kV, both phase to earth and phase to phase. Where the phase-centre distance is below 360 mm, an insulation board is added between the phases to keep the clearance.

The two types share the 31.5 kA 4 s and 80 kA ratings and the same five phase-centre distances and outline dimensions. The JN22B-40.5 is the variant developed from the JN15 type; it states 35 kV rated voltage with 40.5 kV maximum and quotes IEC 129 and IEC 62271-102.

Five variants at 280, 300, 350, 360 and 400 mm, with overall lengths L of 1010, 1100, 1200, 1200 and 1300 mm respectively. Select the distance that matches the cubicle busbar layout; below 360 mm an inter-phase insulation board is fitted.

JN22-40.5/31.5 Indoor High-Voltage Earthing Switch for KYN61-405