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JN22B-40.5 Indoor Earthing Switch
JN22B-40.5 indoor earthing switch is a three-phase high-voltage grounding device rated at 40.5kV, designed for installation in medium voltage switchgear operating at 35kV and 40.5kV systems. Built to IEC 62271-102, this earthing switch features upgraded 40.5kV epoxy resin insulators with exceptional dielectric strength and arc resistance, a spring-loaded rapid closing mechanism for fault-making earthing applications, and a central drive shaft for synchronized three-phase operation. This high-speed earthing switch serves utility transmission-class substations, heavy industrial power systems, and large-scale renewable energy plants where higher voltage grounding is required.
- Overview
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- Technical Data
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- Quality Control
- Recommended Products
JN22B-40.5 High-Speed Vacuum Earthing Switch - 35kV / 40.5kV
JN22B-40.5 is a three-pole high-speed earthing switch for 35kV and 40.5kV systems, using vacuum interrupters as the making elements. It is installed in KYN61-40.5 metal-clad switchgear and equivalent 40.5kV panels, providing fault-making earthing capability at the highest distribution voltage class in our range.
WHY 35kV NEEDS A DIFFERENT APPROACH
At 12kV and 24kV, a conventional blade-type earthing switch can be built with sufficient making capacity using open-air contacts. At 40.5kV the required clearances and the energy released during a fault-close make an open-air design large, slow and difficult to contain. JN22B uses sealed vacuum interrupters as the making elements: the arc is confined inside the vacuum chamber, so the fault-close event is contained rather than being released into the compartment as an open arc.
HIGH-SPEED MAKING
The mechanism is spring-driven and independent of operator speed. Once the operating handle passes its trip point, the spring drives the contacts closed at a fixed high velocity regardless of how slowly or hesitantly the operator moves the lever. This matters because a slow close onto a live circuit produces prolonged pre-arcing, contact erosion and potentially welded contacts. Independent high-speed operation removes operator technique from the safety equation entirely.
WHERE 35kV EARTHING IS REQUIRED
The 40.5kV class serves 35kV networks, which are a mainstream distribution and sub-transmission voltage across Russia and the CIS, and appear in industrial and utility applications in Eastern Europe. In Middle East and African networks, 33kV distribution also falls into this equipment class. These are high-energy circuits where an unintended fault-close carries far greater consequences than at 11kV, which is why fault-making capability is specified rather than optional.
THREE-POLE OPERATION AND INTERLOCKING
All three phases earth simultaneously from a single shaft. Mechanical interlocking with the circuit breaker and cable compartment door enforces the correct sequence: breaker open and withdrawn before earthing, earth applied before compartment access, no rack-in while earthed. Auxiliary switch blocks provide earth-applied status to protection relays and SCADA.
MARKET FIT
Serves 35kV networks in Russia, CIS and Eastern Europe, and 33kV networks in the Middle East and Africa. GOST 15150 climatic versions with low-temperature grease are available for CIS supply, where 35kV rural sub-transmission is extensive and winter access is difficult. ASTA type-test certification available for utility and EPC procurement.
PRIMARY APPLICATIONS
- Cable and busbar earthing in KYN61-40.5 metal-clad switchgear.
- 35kV distribution and sub-transmission substations across Russia and the CIS, where 35kV is a mainstream network voltage.
- 33kV distribution substations in the Middle East and Africa, including Saudi Arabian SEC networks and Nigerian and Kenyan 33kV distribution.
- Industrial plant 35kV incoming substations: mining, metallurgy, cement, petrochemical.
- Renewable generation collection substations stepping up to 33kV or 35kV.
- Utility substations where prospective fault current and system energy demand fault-making earthing rather than simple isolation earthing.
- Bus-section and bus-coupler earthing in 40.5kV switchgear lineups.
- Transformer primary circuit earthing before maintenance on 35kV units.
WHY FAULT-MAKING CAPABILITY IS SPECIFIED AT THIS VOLTAGE
At 35kV the stored energy in a fault is far greater than at 11kV, and the consequences of a hesitant or failed earthing operation are correspondingly more severe. Utility specifications at this voltage class routinely require an earthing switch capable of closing onto a live circuit and holding the fault current until upstream protection operates. A switch rated only for isolation earthing is not compliant with these specifications.
REGIONAL FIT
- Russia and CIS: 35kV is a core distribution and sub-transmission voltage with extensive rural networks. GOST R certification, GOST 15150 climatic versions for low-temperature service.
- Eastern Europe: 35kV industrial and utility applications to EN 62271-102.
- Middle East: 33kV distribution, notably Saudi Arabian SEC networks, subject to utility material approval and often witnessed type testing.
- Africa: 33kV distribution across Nigeria, Kenya, Ghana, Tanzania and South Africa.
NOT SUITABLE FOR
Systems at 12kV and 24kV - specify JN15A-12 or JN17, which are correct and considerably more economical. Outdoor installation without an enclosure. Applications where only isolation earthing without fault-making duty is required and the lower voltage classes apply.
TECHNICAL DATA - JN22B-40.5 High-Speed Vacuum Earthing Switch
| Item | Specification |
| Compliance | IEC 62271‑102, GB 1985 |
| ELECTRICAL RATINGS | |
| Rated voltage | 40.5 kV |
| Rated frequency | 50 Hz / 60 Hz |
| Rated power‑frequency withstand voltage (1 min) | 95 kV to earth / 118 kV across isolating distance |
| Rated lightning impulse withstand voltage (BIL) | 185 kV peak / 215 kV across isolating distance |
| Rated short‑circuit making current | 63 kA / 80 kA peak |
| Rated short‑time withstand current | 25 kA / 31.5 kA for 4 s |
| Rated peak withstand current | 63 kA / 80 kA |
| Number of poles | 3, simultaneous operation from a single shaft |
| MAKING ELEMENT | |
| Type | sealed vacuum interrupter, one per pole |
| Arc containment | fully contained within the vacuum chamber during fault‑close |
| Mechanism | spring‑driven, high‑speed closing independent of operator speed |
| Closing velocity | fixed by spring energy, not operator technique |
| OPERATION | |
| Manual | lever operation with spring‑assisted high‑speed closing |
| Motorised (optional) | AC/DC 110 V or 220 V motor operator with local manual override |
| Position indication | mechanical indicator, direct‑driven from the main shaft |
| Auxiliary switch | up to 6NO6NC |
| Interlocking | mechanical interlock with circuit breaker and cable compartment door |
| Padlocking | provision in both open and earthed positions |
| ENDURANCE | |
| Mechanical life | 2,000 operations minimum |
| Making operations at rated making current | 2 operations minimum |
| CONSTRUCTION | |
| Vacuum interrupter | sealed ceramic envelope, one per phase |
| Support insulators | cycloaliphatic epoxy resin, 185 kV BIL rated |
| Frame | hot‑dip galvanised or powder‑coated steel |
| Earthing terminal | M12 / M16 bolt for main earth conductor |
| Mounting | KYN61‑40.5 and equivalent 40.5 kV metal‑clad panels |
| Weight | approximately 60‑90 kg |
| SERVICE CONDITIONS | |
| Ambient temperature | ‑25 ℃ to +55 ℃ |
| Altitude | up to 1000 m standard; up to 2000 m on request |
| Relative humidity | daily average not exceeding 95% |
| Installation | indoor, within metal‑enclosed switchgear |
| CERTIFICATION | |
| Certification | Type tested to IEC 62271‑102; ASTA type‑test certificate available on request |
OPTIONS
Motorised operator AC/DC 110 V or 220 V | additional auxiliary contacts | position sensor for SCADA signalling | padlocking kit | extended operating shaft | low-temperature grease for GOST 15150 climatic versions | ASTA type-test certification | custom mounting to suit non-standard 40.5 kV panels
PRE-SALES SELECTION
- Application review against your duty: rated current, breaking capacity, operating sequence, and expected switching frequency.
- Retrofit and replacement sizing. Send us the existing unit's model, pole-centre distance and mounting dimensions and we will confirm interchangeability before you order.
- Grid verification: 12kV class for 10kV (Russia/CIS) and 11kV (Middle East/Africa) networks; 24kV for 20kV and 22kV; 40.5kV for 35kV. Saudi Arabian supply verified at 60Hz.
- Coil, motor and auxiliary-contact configuration specified to your control voltage (AC/DC 110V or 220V) and SCADA interface requirement.
- Low-temperature variants with cold-rated grease and anti-condensation heating for CIS winter service.
MARKET ACCESS AND DOCUMENTATION
- Type-test reports to IEC 62271-100 / IEC 62271-102 / IEC 62271-103 as applicable, issued with the shipment.
- Third-party certification (KEMA, ASTA, CESI, TUV) available where tender documents require witnessed evidence rather than a manufacturer's report.
- Certification support for SASO SABER, SONCAP, KEBS PVoC, ICIGI and GOST R submissions, including HS-code classification (Nigeria has required 10-digit HS codes since March 2025).
TESTING AND DELIVERY
- 100% routine testing before dispatch: power-frequency withstand, contact resistance, mechanical characteristic curve, timing test, and auxiliary circuit verification.
- Individual test report supplied per serial number.
- Export packing with desiccant and moisture barrier; palletised for consolidated shipment.
- Documentation: routine test report, type-test certificate, dimensional drawing, wiring schematic, O&M manual, spare parts list.
AFTER-SALES
- Installation and commissioning guidance, remote support or engineer dispatch.
- Maintenance training covering mechanism inspection, contact wear measurement and vacuum interrupter integrity testing.
- Wear parts (coils, contacts, mechanism components) held in stock for rapid replacement.
- Technical response within 24 hours; multilingual manuals in English, Russian, French and Arabic.
- Warranty: 18 months from delivery or 12 months from commissioning, whichever expires first.
TYPE TESTING
- Type tested to the applicable IEC standard - IEC 62271-100 for circuit breakers, IEC 62271-102 for earthing switches and disconnectors, IEC 62271-103 for load break switches.
- Verified for rated short-circuit breaking and making capacity, short-time withstand current, power-frequency and lightning impulse withstand, temperature rise, and mechanical endurance across the full rated operating sequence.
- Third-party certification from KEMA, ASTA, CESI or TUV available where the tender requires witnessed evidence.
VACUUM INTERRUPTER CONTROL (where applicable)
- Every interrupter is vacuum-integrity tested before assembly; vacuum degradation is the dominant failure mode in a VCB and is not visible externally once installed.
- Contact stroke, over-travel and contact wear allowance measured and recorded per pole.
- Interrupters sourced only from qualified manufacturers with batch traceability.
IN-PROCESS INSPECTION
- Insulating components partial-discharge tested before assembly.
- Mechanism spring force and charging characteristic verified against specification.
- Pole-centre distance and mounting interface dimensions checked against drawing - critical for retrofit interchangeability.
- Plating thickness on current-carrying contacts verified per batch.
ROUTINE TESTING - 100%, NO SAMPLING
- Power-frequency withstand voltage across the open contacts and to earth.
- Main circuit contact resistance measurement.
- Mechanical characteristic curve: closing time, opening time, contact bounce, and three-phase simultaneity.
- Operating mechanism function at minimum, rated and maximum control voltage - a unit that only operates at nominal voltage will fail during a real disturbance when station battery voltage sags.
- Auxiliary switch continuity and position signalling verification.
- Serialised routine test report issued with every unit.
TRACEABILITY AND SYSTEM
- ISO 9001 quality management system.
- Serial number traceability to vacuum interrupter batch, mechanism batch and insulation component batch.
- Test records retained for the warranty period and available on request.
ENVIRONMENTAL QUALIFICATION
Where the destination environment exceeds IEC reference conditions we qualify against it: elevated-ambient temperature-rise verification for Gulf service, salt-spray testing for coastal sites, and low-temperature operation verification with cold-rated lubricant for GOST 15150 climatic versions.
