JN22B-40.5 Indoor Earthing Switch 35/40.5kV | 31.5kA HV Grounding Switch | IEC 62271-102

Product Overview

The JN22B-40.5/31.5 is an indoor high-voltage earthing switch developed from the JN15 type for 40.5 kV maximum voltage (35 kV rated), 50 Hz systems, compliant with IEC 129 and IEC 62271-102. It matches KYN□-40.5 and other metal-enclosed switchgear as the earthing-protection element: once the feeder is isolated and proved dead, its three earth knives bond the circuit to earth, interlocked with the switchgear or door against mal-operation. Silver-plated contacts make short-circuit current; the switch carries 31.5 kA for 4 s with 80 kA peak; five phase-centre distances of 280-400 mm are offered.

Product Display

JN22B-40.5 Indoor High-Voltage Earthing Switch - display

JN22B-40.5 Indoor High-Voltage Earthing Switch - poster_display

Model Designation

JN22B-40.5 Indoor High-Voltage Earthing Switch - model

Model format: JN 22B – 40.5 / 31.5 – □

JN – indoor earthing switch
22B – design number
40.5 – maximum (rated) voltage, kV
31.5 – 4 s thermal-stability (short-time withstand) current, kA
□ – central distance between poles, mm
Example: JN22B-40.5/31.5-360 is the 31.5 kA type with 360 mm pole centres

Service Conditions

Ambient temperature: -10 °C to +40 °C
Altitude: not above 1000 m
Relative humidity: daily average not above 95%, monthly average not above 90%
Seismic intensity: not above 8 degrees
Site free from corrosive or flammable gas and without frequently intense vibration

Construction

The three earth knives are carried on support insulators above a common frame and are driven through a transmission shaft by a manual operating mechanism, so all three poles make or break the earth connection together with fast opening and closing. The knives engage silver-plated 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, ensuring the knives close only on an isolated, de-energised 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; the simple structure eases installation, commissioning and adjustment.

Technical Data

Item	Unit	Data
Rated voltage	kV	35
Maximum (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 (between-pole) distance	mm	280 / 300 / 350 / 360 / 400
1 min power-frequency withstand voltage (phase to earth)	kV	95
Lightning impulse withstand voltage (phase to earth)	kV	185
Standard	—	IEC 129; IEC 62271-102

Selection note: Confirm that the system voltage (35 kV rated, 40.5 kV maximum) and the prospective fault current fall within the 31.5 kA 4 s short-time and 80 kA peak ratings, then choose the phase-centre distance, 280, 300, 350, 360 or 400 mm, to suit the cubicle busbar layout; below 360 mm an inter-phase insulation board is fitted. The manual three-pole mechanism is interlockable with the switchgear or cubicle door; state the full model, ratings, pole distance and any accessory requirement when ordering.

Standards

Performance of the JN22B-40.5 complies with IEC 129 and IEC 62271-102 for high-voltage earthing switches. The rated parameter table of the type datasheet lists the switch at 35 kV rated voltage with 40.5 kV maximum voltage, the 95 kV power-frequency and 185 kV impulse withstand levels being stated phase to earth.

Technical note: Values are taken from the type datasheet; any special service condition and the delivered ratings follow the order technical agreement and the nameplate, and the certified dimensional drawing for the ordered phase-centre distance governs installation.

Installation & Dimensions

Installation Diagram

JN22B-40.5 Indoor High-Voltage Earthing Switch - installation

Fix the earthing-switch frame to the cubicle mounting plane through the 20 x 9 x 19 oval holes at the selected phase-centre distance, keeping the earth knives and silver-plated static contacts clear of obstructions. Couple the three poles to the manual 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. Catalogue dimensions are for cubicle preparation only; confirm the certified dimensional drawing for the ordered phase-centre distance.

Model	E (mm)	G (mm)	L (mm)	D (mm)
JN22B-40.5/31.5-280	280	290	1010	656
JN22B-40.5/31.5-300	300	340	1100	696
JN22B-40.5/31.5-350	350	340	1200	796
JN22B-40.5/31.5-360	360	320	1200	816
JN22B-40.5/31.5-400	400	340	1300	896

Safety notice: The JN22B-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 withstands and makes short-circuit current but breaks no load current, and installation and operation must be carried out by qualified personnel with the frame bonded to the earth network.

FAQs

JN identifies an indoor earthing switch and 22B the design number; 40.5 is the maximum voltage in kV and 31.5 the 4 s short-time withstand current in kA. The trailing figure gives the central distance between poles in millimetres.

It is an indoor medium-voltage earthing switch developed from the JN15 type, matching KYN□-40.5 and other metal-enclosed switchgear as the earthing-protection element in 40.5 kV, 50 Hz systems. It bonds the isolated, de-energised circuit to earth during inspection and maintenance.

Rated voltage 35 kV with a maximum voltage of 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. It carries fault current but breaks no load current.

Its performance complies with IEC 129 and IEC 62271-102 for earthing switches. The 1 min power-frequency withstand voltage is 95 kV and the lightning impulse withstand voltage 185 kV, both phase to earth.

Both share the 31.5 kA 4 s and 80 kA ratings, the five phase-centre distances of 280-400 mm and identical outline dimensions. The JN22B is the variant developed from the JN15 type with silver-plated static contacts, a manual mechanism and stated 35 kV rated / 40.5 kV maximum voltage, while the KYN61-matched JN22-40.5 lists 40.5 kV as its rated voltage.

Five variants at 280, 300, 350, 360 and 400 mm, with overall lengths L of 1010, 1100, 1200, 1200 and 1300 mm respectively. Where the phase-centre distance is below 360 mm an insulation board is added between the phases.

JN22B-40.5 Indoor High-Voltage Earthing Switch HV Grounding Switch