EN
JN17-12 Motorized Earthing Switch
JN17-12 motorized earthing switch is a three-phase automated grounding device rated at 12kV, designed for remote operation in medium voltage switchgear. Built to IEC 62271-102, this motorized earthing switch features an integrated motor drive for remote closing and opening, a spring-loaded rapid closing mechanism, and epoxy resin insulators for high dielectric strength. The epoxy-encapsulated position sensor provides open/close status feedback to protection relay panels. Rated for 80kA peak making current and 31.5kA short-time withstand, this indoor earthing switch supports SCADA-controlled substations, utility distribution networks, and industrial facilities requiring automated grounding operations.
- Overview
- Applications
- Technical Data
- Services
- Quality Control
- Recommended Products
JN17 Series Earthing Switch - 12kV / 24kV, Manual or Motorised
JN17 series is a three-pole indoor earthing switch available in 12kV (JN17-12) and 24kV (JN17-24) ratings, with manual or motorised operation. It is the higher-duty alternative to the JN15A-12, offering 80kA peak short-circuit making capacity, 31.5kA short-time withstand, an integral auxiliary switch and the option of remote motorised earthing.
HIGHER MAKING CAPACITY - WHY IT MATTERS
An earthing switch may be closed onto a circuit that is still live. At 80kA peak making current, JN17 handles a fault-close on networks with high upstream fault levels - typically utility substations close to the source transformer, industrial plants with large in-plant generation, and any network where the prospective short-circuit current exceeds what a 50kA-rated switch can safely make onto. Specifying making capacity below the site prospective fault current is a common and dangerous procurement error.
MOTORISED OPERATION AND THE UNMANNED SUBSTATION
The motorised variant (AC/DC 110V or 220V) allows the earthing switch to be operated remotely from a control room or SCADA system. This matters increasingly across Gulf utility networks and CIS distribution, where substations are unmanned and the alternative is dispatching a crew simply to apply an earth before maintenance can start. Remote earthing removes travel time from the outage window and keeps operators out of the switchroom during the switching sequence.
POSITION FEEDBACK
JN17-12/50 variant includes an epoxy-encapsulated position sensor providing reliable open and earthed signalling to protection relays and SCADA. Encapsulation matters: a conventional microswitch in a dusty, humid switchgear compartment is a known long-term reliability weak point, and a false "earth applied" indication is a serious safety issue. An integral auxiliary switch block up to 4NO4NC is standard across the series.
THREE-POLE SIMULTANEOUS OPERATION AND INTERLOCKING
All three phases earth simultaneously from a single shaft. Mechanical interlocking with the circuit breaker and cable compartment door enforces the safe sequence in hardware: breaker open and withdrawn before earthing, earth applied before compartment access, and no breaker rack-in while earthed.
MARKET FIT
JN17-12 serves 11kV Middle East and African networks and 10kV Russian, CIS and Eastern European networks. JN17-24 serves 22kV Gulf networks and 20kV Eastern European and CIS networks. ASTA type-test certification available for utility and EPC procurement. GOST 15150 climatic versions with low-temperature grease available for CIS supply.
PRIMARY APPLICATIONS
- Cable compartment earthing in KYN28-12 and KYN28-24 metal-clad switchgear.
- Utility substations with high prospective fault current, where 50kA making capacity is insufficient.
- Unmanned and remotely operated substations requiring motorised earthing from a control room or SCADA system.
- Busbar earthing in bus-section and bus-riser panels.
- Industrial plants with in-plant generation, where fault levels are elevated by local synchronous machines.
- 22kV and 20kV distribution panels requiring the 24kV rated JN17-24.
- Substations under SCADA automation programmes, where every switching operation including earthing is remotely controlled.
- Transformer and feeder circuit earthing before maintenance.
- Retrofit upgrade where an existing 50kA earthing switch is inadequate for an increased network fault level - a common situation as networks are reinforced.
SELECTING BETWEEN JN15A AND JN17
Specify JN15A-12 where the network fault level is within 50kA peak making, operation is manual and local, and cost governs. Specify JN17 where the prospective fault current exceeds 50kA peak, remote motorised earthing is required, integral position feedback to SCADA is needed, or the system voltage is 24kV.
REGIONAL FIT
- Middle East: 11kV and 22kV networks. Motorised earthing aligns with Gulf utility SCADA automation programmes; ASTA certification frequently required by SEC, DEWA and KAHRAMAA procurement.
- Africa: 11kV networks, particularly utility substations near source transformers where fault levels are high.
- Russia and CIS: 10kV and 20kV networks, GOST R certified. Motorised operation is especially valuable where winter access to remote substations is difficult.
- Eastern Europe: 10kV and 20kV networks to EN 62271-102.
NOT SUITABLE FOR
Outdoor installation without an enclosure. Systems at 35kV and 40.5kV requiring high-speed fault-making earthing - specify JN22. Applications where the simpler JN15A-12 is adequate and cost governs.
TECHNICAL DATA - JN17-12 / JN17-24 Earthing Switch
| Item | Specification |
| Compliance | IEC 62271‑102, GB 1985 |
| ELECTRICAL RATINGS‑JN17‑12 | |
| Rated voltage | 12 kV |
| Rated power‑frequency withstand voltage (1 min) | 42 kV to earth / 48 kV across isolating distance |
| Rated lightning impulse withstand voltage (BIL) | 75 kV peak / 85 kV across isolating distance |
| Rated short‑circuit making current | 80 kA peak |
| Rated short‑time withstand current | 31.5 kA for 4 s |
| Rated peak withstand current | 80 kA |
| ELECTRICAL RATINGS‑JN17‑24 | |
| Rated voltage | 24 kV |
| Rated power‑frequency withstand voltage (1 min) | 50 kV to earth / 60 kV across isolating distance |
| Rated lightning impulse withstand voltage (BIL) | 125 kV peak / 145 kV across isolating distance |
| Rated short‑circuit making current | 63 kA peak |
| Rated short‑time withstand current | 25 kA for 4 s |
| COMMON | |
| Rated frequency | 50 Hz / 60 Hz |
| Number of poles | 3, simultaneous operation from a single shaft |
| OPERATION | |
| Manual | Lever operation, 90 degree operating angle |
| Motorised (optional) | AC/DC 110 V or 220 V motor operator with local manual override |
| Motor operating time | 3‑5 s typical |
| Position indication | Mechanical indicator, direct‑driven from the main shaft |
| Auxiliary switch | Integral, up to 4NO4NC |
| Position sensor (JN17‑12/50) | Epoxy‑encapsulated, providing open and earthed status to relays and SCADA |
| 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 | |
| Contact blade material | Copper alloy, silver plated |
| Support insulators | Cycloaliphatic epoxy resin |
| Frame | Hot‑dip galvanised or powder‑coated steel |
| Earthing terminal | M12 bolt for main earth conductor |
| Mounting | Cable compartment of KYN28‑12 / KYN28‑24 and equivalent panels |
| Weight | Approximately 25‑45 kg depending on rating and motor option |
| 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 | epoxy-encapsulated position sensor | additional auxiliary contacts | padlocking kit | extended operating shaft | low-temperature grease for GOST 15150 climatic versions | ASTA type-test certification | custom mounting to suit non-standard 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.
