3EK7
MV Surge Arrester 3EK7, Silicone rubber, cage design, 10 kA, Ur ≤60 kV
3EK7
- Metal-oxide surge arrester in silicone-rubber cage design for medium-voltage distribution networks, rated voltages 3–60 kV
- Silicone rubber direct-molded onto MOVs and FRP cage rods — void-free sealing against moisture, no sealed shell so overload arcs escape without pressure build-up or ejection of internal parts
- In 10 kA, rated short-circuit current Is 20 kA, high-current impulse 100 kA; very high mechanical performance (SSL up to 2,940 N)
- IEC 60099-4 versions with DH (Qrs 0.5 C) or SL (Qrs 1.2 C) designation, plus IEEE C62.11 energy class B; indoor shedless variants available
- Hydrophobic, self-extinguishing housing for maintenance-free service; protects transformers, circuit breakers, MV switchgear and distribution lines
Transformer protectionMV switchgear and panel protectionCircuit breaker protectionOverhead distribution line protection
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3EK7 covers up to 72.5 kV of the mv distribution arresters range (≤ 72.5 kV across the category, √ scale).
Specifications
Main
| Product family | 3EK7 |
| Product type | Metal-oxide surge arrester |
| Application | Medium-voltage distribution networks |
| Protected equipment | Transformers, circuit breakers, MV switchgear/panels, distribution lines |
Electrical
| Max. system voltage Us | 72.5 kV |
| Max. rated voltage Ur | 60 kV |
| Min. system voltage | 3.6 kV |
| Continuous operating voltage Uc | 2.4–48 kV (0.8 × Ur) |
| Nominal discharge current In | 10 kA |
| Short-circuit rating Isc | 20 kA |
| High-current impulse | 100 kA |
| Line discharge class | 2 |
Energy handling (IEC 60099-4 / IEEE C62.11)
| DH designation (order code 4) | Charge transfer rating Qrs 0.5 C, thermal charge transfer rating Qth 1.1 C |
| SL designation (order code 5) | Charge transfer rating Qrs 1.2 C, thermal energy rating Wth 4.5 kJ/kVr |
| IEEE C62.11 energy class | B — classifying current 10 kA, single-impulse withstand 0.6 C (outdoor), switching-surge energy rating 4.5 kJ/kVMCOV |
Protection levels (residual voltage, 8/20 µs 10 kA)
| 3EK7 120-4CC4 (Ur 12 kV) | 31.8 kV (20 kA: 36.6 kV; 30/60 µs 500 A: 24.5 kV) |
| 3EK7 360-4CH4 (Ur 36 kV) | 95.4 kV (20 kA: 110 kV; 30/60 µs 500 A: 73.5 kV) |
| 3EK7 600-4CJ4 (Ur 60 kV) | 159 kV (20 kA: 183 kV; 30/60 µs 500 A: 122 kV) |
Mechanical / environment
| Housing material | silicone |
| Design | Silicone-rubber cage design — MOVs in fiber-reinforced plastic (FRP) rod cage, silicone direct-molded, no internal gas volume |
| Housing heights | 170–510 mm (types B–K), outdoor with alternating sheds; indoor version shedless 170–510 mm |
| Creepage distance | 372–1,595 mm (outdoor IEC versions) |
| Specified short-term load SSL | 2,940 N (housing B) down to 980 N (housing K); with insulating bracket 470–150 N |
| Specified long-term load SLL | 2,050 N (housing B) down to 680 N (housing K); with insulating bracket 320–100 N |
| Weight | approx. 1.5–5.4 kg (outdoor, without accessories) |
| Housing properties | Hydrophobic, tracking/erosion resistant, self-extinguishing, flame-retardant |
| Disconnector option | Earth-terminal disconnector available for distribution systems, non-pyrotechnic (spare part 3EX4 065-7A for 3/8″ thread, 3EX4 065-7C for M12) |
Standards & certifications
| Standards | IEC 60099-4, IEEE C62.11 |
| Withstand (example, housing B outdoor) | LIWV 1.2/50 µs 104 kV, power-frequency wet 1 min 49 kV |
Options & variants
Representative catalog ratings (MV Surge Arrester Catalog LS 2026-01-30, pp. 18–25). Order code: 3EK7 <Ur×10> – <4=DH 0.5 C | 5=SL 1.2 C | 3=IEEE heavy duty> <C=IEC | A=IEEE> <housing B–K> <4=alternating sheds | 0=shedless indoor>. Top-ordered SAP material 3EK71003AB4 ("10 kV Heavy Duty") = the IEEE 10 kV duty-cycle / MCOV 8.4 kV row below.
| Order No. | Standard / designation | Ur (kV) | Uc / MCOV (kV) | In (kA) | Housing H (mm) | Creepage (mm) |
|---|---|---|---|---|---|---|
| 3EK7 100-3AB4 | IEEE C62.11 · class B heavy duty | 10 (duty cycle) | 8.4 | 10 | 170 (6.7 in) | 371 (14.6 in) |
| 3EK7 120-4CC4 | IEC 60099-4 · DH | 12 | 9.6 | 10 | 200 | 485 |
| 3EK7 240-4CE4 | IEC 60099-4 · DH | 24 | 19.2 | 10 | 270 | 775 |
| 3EK7 360-4CH4 | IEC 60099-4 · DH | 36 | 28.8 | 10 | 400 | 1230 |
| 3EK7 600-4CJ4 | IEC 60099-4 · DH | 60 | 48.0 | 10 | 470 | 1420 |
| 3EK7 360-5CJ4 | IEC 60099-4 · SL | 36 | 28.8 | 10 | 470 | 1420 |
| 3EK7 360-4CH0 | IEC 60099-4 · DH indoor (shedless) | 36 | 28.8 | 10 | 400 | 387 |
Compatible accessories
Line terminals
Line clamp, ø8–18 mm
3EX4 063-0C
Line terminals
L-bracket
3EX4 063-1C
Line terminals
Line clamp, stainless steel
3EX4 063-2C
Line terminals
Line clamp for cable shoe
3EX4 063-5C
Line terminals
Line clamp for cable shoe (NEMA)
3EX4 063-5A
Protection
Bird protection cap
3EX4 128-0A
Protection
Bird protection cap XL
3EX4 128-4A
Brackets
Metal bracket (NEMA)
3EX4 080-1A
Brackets
Metal bracket (DIN)
3EX4 080-2A
Brackets
Insulating bracket (NEMA)
3EX4 080-1C
Brackets
Insulating bracket (DIN)
3EX4 080-2C
Transformer brackets
Transformer bracket, size 1
Transformer brackets
Transformer bracket, size 2
Transformer brackets
Transformer bracket, size 3
Transformer brackets
Transformer bracket, size 4
Pole mounting
Cross-arm bracket
Leads
Lead wire, insulated
Leads
Earth lead, flexible
Leads
Earth lead, rigid
Documents & downloads
Catalog Medium-Voltage Surge Arresters Catalog (3EK section pp. 16–29)
Mini-catalog MiniKat 3EK7 IEC — selection & dimensions
Mini-catalog MiniKat 3EK7 IEC SL — selection & dimensions
Also covered in the technical library
Catalog Medium-Voltage Surge Arresters — Product Catalogue
Catalog Medium-voltage surge arresters — Siemens Energy catalog (online edition)
Brochure Our portfolio of surge arresters & composite insulators — Siemens Energy
Ordered designations
Representative orderable type designations of this family — searchable via the catalog search.
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3EJ0