3EK / 3EJ / 3EH4 / 3EP-G — medium-voltage surge arresters up to 72.5 kV
3EK, 3EJ, 3EH4 and 3EP-G are medium-voltage surge arresters for distribution networks and equipment of classes up to 72.5 kV. They protect transformers, circuit breakers, switchgear cubicles, lines, generators and motors, arc furnaces and capacitor banks. Applications cover 6–35 kV distribution networks, power plants, industry, cable networks and medium-voltage GIS.
- Network class
- up to 72.5 kV
- 3EK7 / 3EK8
- distribution arresters: Cage Design™ / glass fabric wrap, silicone
- 3EJ2/3EJ3/3EJ4
- increased energy capability, Ur up to 54 kV (3EJ4 also for indoor installation)
- 3EJ0/3EJ9
- very low protection level, Ur up to 15 kV (cable networks, power plants)
Price, availability and lead time on request. We help with analogue selection, customs clearance and delivery.
Description
The list of protected equipment is wider than usual. It includes furnace and dry-type transformers, airfield lighting systems, cable sheaths and drive converters. All arresters are built on metal-oxide varistors of the company's own production without spark gaps and tested to IEC 60099-4. They can also be ordered through the manufacturer's online store.
The 3EK family consists of distribution arresters. 3EK7 has Cage Design™ construction. A frame of fiberglass rods provides mechanical strength, and silicone is molded directly onto the varistors, so moisture and partial discharges are excluded. In 3EK8 the varistors are wrapped in glass fabric, onto which silicone is also molded directly. In an overload the arc exits without mechanical destruction. A non-explosive disconnector is provided, and there are versions for outdoor and indoor installation with a smooth housing. For networks passing through fire-prone vegetation, variants based on 3EK7 are offered that reduce sparking and ignition if an arrester fails. They are 3EK7 with an arc-preventing disconnector, 3EK4 with an arc protection system and 3EK7 with a spark-reducing terminal. Some arresters are fitted with a visible failure indicator, so the crew quickly finds the failed device.
The 3EJ family also has Cage Design™ and stands out with increased energy capability at a low protection level. It is used on generators, motors, arc furnaces, dry-type transformers, cable sheaths, capacitors and converters. Types 3EJ2, 3EJ3 and 3EJ4 have a rated voltage up to 54 kV and medium, high and very high energy capability respectively; 3EJ4 is also available in an indoor version. 3EJ0 and 3EJ9 with a rated voltage up to 15 kV give a very low residual voltage. They are recommended for cable networks and power plants.
Plug-in arresters 3EH4 for voltages up to 52.5 kV have connectors under EN 50180/EN 50181 with an inner cone of sizes 2 and 3, class DH. They are connected directly to GIS and transformers, and the protection level is matched to the impulse strength of that equipment.
Porcelain 3EP-G have a directional pressure relief system and withstand a short-circuit current up to 300 kA. They are intended for generators and large motors.
Technical specifications
| Network class | up to 72.5 kV |
|---|---|
| 3EK7 / 3EK8 | distribution arresters: Cage Design™ / glass fabric wrap, silicone |
| 3EJ2/3EJ3/3EJ4 | increased energy capability, Ur up to 54 kV (3EJ4 also for indoor installation) |
| 3EJ0/3EJ9 | very low protection level, Ur up to 15 kV (cable networks, power plants) |
| 3EH4 | plug-in arresters up to 52.5 kV, connectors under EN 50180/50181 (inner cone, sizes 2 and 3) |
| 3EP-G | porcelain, for generators and motors, short-circuit withstand up to 300 kA |
| Standard | IEC 60099-4 |
Request a price and lead time
3EK / 3EJ / 3EH4 / 3EP-G — medium-voltage surge arresters up to 72.5 kV. We reply within one business day.
Or email sales@usk.ua or call 044 339-50-20.
Customs codes
| UKTZED (Ukraine) | 8535 40 00 00 |
|---|---|
| HS, 6 digits | 8535 40 |
| CN (EU) | 8535 40 00 |
| HTSUS (USA) | 8535 40 00 00 |
| China customs tariff | 8535 40 00 00 |
Codes are for reference: the final code is determined at declaration for the specific model.
Questions and answers
Which arrester should be chosen to protect a generator?
The porcelain 3EP-G, which withstands a short-circuit current up to 300 kA, is intended for generators and large motors. 3EJ with increased energy capability and a rated voltage up to 54 kV is also suitable.
Can an arrester be connected directly to medium-voltage GIS?
Yes, plug-in 3EH4 for voltages up to 52.5 kV with connectors under EN 50180/EN 50181 are made for this. They have an inner cone of sizes 2 and 3.
Which arrester gives the lowest residual voltage for a cable network?
3EJ0 and 3EJ9 with a rated voltage up to 15 kV have a very low residual voltage. They are recommended for cable networks and power plants.
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