3EK7 Surge Arrester up to 52 kV– safer with silicone

The New 3EK7: durable, safe, top quality

The new 3EK7 surge arrest-

er from Siemens offers

superior protection against

power surges for the

equipment in electrical

distribution systems with

operating voltages of up to

52 kV.

Besides being highly resistant

to environmental pollution of

all kinds, its performance in

dealing with earth faults and

its excellent short-circuit

ratings are setting entirely

new standards.

The silicone on the new 3EK7

surge arrester refuses to

allow any deposits of pollution

or films of moisture to form

on it. Thus surface currents

caused by pollution are

extremely low.

This arrester is also very

lightweight, robust and du-

rable – and offers outstanding

cost effectiveness.

Silicone:

Total safety

Together, the water-repellent(hydrophobic) property of thesilicone and the elasticity ofthe synthetic composite mate-rial ensure that the 3EK7 surgearrester enjoys an exceptio-nally long service life, evenunder the toughest climaticconditions and in the harshestindustrial environment.Moreover, it does not give offany toxic substances, even inthe event of fire.

Silicone:

Exceptional resistance to

surface pollution

The silicone on the 3EK7surge arrester preventsmoisture and pollution fromsettling on its surface.Because this water-repellentproperty is also transferred tocontaminant layers, it isimpossible for a completelayer of conductive moistureto form on the surface. Eventhe heavy saline fog thatoccurs in coastal regions hasno adverse effect on theexcellent dielectric properties.The end result is that nosurface currents can begenerated, and dischargeson the surface of the arrest-er are minimal.

Stays leak-tight for years

The silicone enclosuresprayed directly onto themetal-oxide resistors of the3EK7 surge arrester has anumber of significantadvantages. Unlikeconventional arresters withsynthetic enclosures that areeither push-fit or shrink-fit,the construction of the 3EK7means that there is no chanceof there being any holes orcavities that moisture mightcreep into – one of the mostcommon causes of failure inmedium-voltage surgearresters. The 3EK7 remainsabsolutely leak-tight andcompletely insensitive tomoisture, no matter what theweather.

Exceptional service life

High-quality materials and thelatest manufacturingtechniques ensure that the3EK7 surge arrester has along service life. The excellentmechanical strength of thesilicone sheath providesoptimum protection of the3EK7 under all conditions –during transport andinstallation, and in serviceagainst wind, weather andwilful attempts to causedamage. This means, ofcourse, that power supplysystem outage times are keptto an absolute minimum.

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Nothing but advantages

• Long service life• Safe overload characteristics• Resistant to damage arising

from transport, installation, storm, earthquake or vandalism

• High UV resistance• High creepage current and

erosion resistance• Suitable for corrosive

atmospheres (industrial, coastal and desert)

• Long-time water repellence(hydrophobic transfer and regeneration)

• Low-temperature flexibility down to – 45 °C

• Highly flame-retardant(selfextinguishing, IEC 707(3 mm) F V0)

• 50% lighter than comparableporcelain surge arresters

• Easy to install• Excellent economy – long

service life, attractive price

Safe overload

characteristics

The metal-oxide resistors ofthe 3EK7 surge arrester aresurrounded by glass-rein-forced plastic rods that en-close them like a cage. In theevent of the resistors beingoverloaded – an extremelyrare event but neverthelessone that cannot be ruled outentirely with any type ofarrester – it is impossible forarcing to generate excessiveinternal pressure because theresistors are not enclosed ina sealed mechanical shell. Thearc can escape through thesilicone sheath without ab-ruptly ripping open the me-chanical supporting structureof the enclosure. At the sametime a large number of GRProds ensure that the metal-oxide resistors remain inplace, reducing to an absoluteminimum the risk of any flyingfragments.

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Totally convincing design

The key design features ofthe 3EK7 surge arrester arethe way in which the HTVsilicone (High TemperatureVulcanizing) is vulcanizeddirectly onto the resistor unitsand the way in which theresistor stacks are clampedsolidly between the endfittings by 8 GRP rods. Theend result of this type ofconstruction is absolute leak-tightness and high mechanicalstrength combined with theability to prevent any buildupof excessive internal pressureas a result of overloading.In addition, compared withother polymers, the HTVsilicone of the enclosure iswater-repellent and flame-retardant, and has been usedwith great success in all typesof power systems for over 20years (including extra-high-voltage networks).

The 3EK7 surge arrester

offers truly sophisticated

technology that can take even

the hardest of knocks in

everyday service. It means,

of course, that it can handle

overloads extremely well,

should they ever occur, and

that there is almost no chance

at all of nearby equipment

suffering secondary damage

(due to flying splinters or

fragments).

Technology that is totally convincing

Passed with flying colors:

All current standard tests

It would be difficult to providea more convincing demon-stration of quality – the 3EK7surge arrester passed all thetests demanded by currentstandards with flying colors.So the whole range complieswith all the latest issues ofIEC 60099-1, 60099-4 andANSI/IEEE C62.11.

Comprehensive range of

accessories

The standard versions of the3EK7 surge arrester comepreassembled with a nut andwasher on the M12 stud ateach end and with anadditional clamp at the high-voltage end. This enables thearrester to be installed inexisting plants in a variety ofways without the need forany additional parts.

With the aid of metal clipsfrom the range of accessoriesit is also possible to mountthis arrester on NEMA or DINterminals. An insulatedmounting must be employedfor the arrester when adisconnector is used. Thereare suitable insulating clipsavailable for this purpose andthey are also suitable forNEMA and DIN terminals.

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Always the Right Type for you

The Siemens 3EK7 surgearrester can be used for allcustomary applications up to52 kV. This enables you tomake unlimited use of all thetechnical and economicadvantages of the 3EK7.

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Electrical data

*Other sizes of enclosure available to order.

Mechanical data

Supply system Supply sys- Supply sys- Surge Enclosure Rated Contin- Maximum residual voltage with wavewith isolated tem with sol- tem with im- arrester size* voltage uousor resonant idly earthed pedance ear- type operatingearthed neutral neutral thed neutral voltage

30/60 µs 8/20 µsUm Um Um Ur Uc 500 A 5.0 kA 10.0 kA 20.0 kAkV kV kV kV kV kV kV kV kV

7.2 3EK7 060-4C S 6 4.8 13.7 16.6 18.0 20.67.2 7.2 3EK7 090-4C S 9 7.2 23.0 27.8 30.2 34.5

12 3EK7 105-4C S 10.5 8.4 25.2 30.5 33.1 37.812 12 3EK7 120-4C S 12 9.6 29.8 36.1 39.2 44.7

12 17.5 12 3EK7 150-4C S 15 12 34.5 41.7 45.3 51.712 3EK7 150-4V S 15 12 30.4 36.8 39.9 45.5

17.5 17.5 3EK7 180-4C M 18 14.4 41.3 50.0 54.3 62.024 17.5 3EK7 210-4C M 21 16.8 46.0 55.6 60.4 68.930 24 3EK7 240-4C L 24 19.2 52.8 63.9 69.4 79.236 24 3EK7 270-4C L 27 21.6 64.3 77.8 84.5 96.4

24 36 3EK7 300-4C L 30 24 68.9 83.4 90.6 103.324 3EK7 300-4V L 30 24 60.7 73.5 79.8 91.0

36 3EK7 360-4C X 36 28.8 80.4 97.3 105.7 120.536 3EK7 390-4C X 39 31.2 87.2 105.6 114.7 130.8

52 3EK7 420-4C X 42 33.6 91.9 111.2 120.8 137.836 52 3EK7 450-4C X 45 36 98.7 119.5 129.8 148.036 3EK7 450-4V X 45 36 87.8 106.2 115.4 131.6

Supply system Supply sys- Supply sys- Surge Enclosure Height Weight Creepage distancewith isolated tem with sol- tem with im- arrester sizeor resonant idly earthed pedance ear- typeearthed neutral neutral thed neutral

Um Um Um kkV kV kV mm kg mm

7.2 3EK7 060-4C S 205 1.9 4907.2 7.2 3EK7 090-4C S 205 2.0 490

12 3EK7 105-4C S 205 2.1 49012 12 3EK7 120-4C S 205 2.1 490

12 17.5 12 3EK7 150-4C S 205 2.2 49012 3EK7 150-4V S 205 2.2 490

17.5 17.5 3EK7 180-4C M 240 2.5 60024 17.5 3EK7 210-4C M 240 2.6 60030 24 3EK7 240-4C L 305 3.2 90036 24 3EK7 270-4C L 305 3.4 900

24 36 3EK7 300-4C L 305 3.4 90024 3EK7 300-4V L 305 3.4 900

36 3EK7 360-4C X 435 4.6 137036 3EK7 390-4C X 435 4.7 1370

52 3EK7 420-4C X 435 4.7 137036 52 3EK7 450-4C X 435 4.8 137036 3EK7 450-4V X 435 4.8 1370

It is very easy to order a Siemens3EK7 surge arrester using thetable below:Simply choose the standard, thesize of enclosure and the type ofterminal from the list, and theorder code will practically compileitself.

Description Order code

NEMA metal clip 3EX4 061DIN metal clip 3EX4 062

NEMA insulating clip 3EX4 060DIN insulating clip 3EX4 066

Arrester disconnector 3EX4 065

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Ordering so easy

Compiling an order code:

3 E K 7 2 1 0 - 4 C M 4 1 - 0 D

Ratedvoltage 21kV

Standard IEC

Enclosure size Medium

Terminal, top(clamp, washer, nut)

Terminal, bottom(DIN metal clip, washer, nut)

Structure of the order code:

Order of accessory parts:

1 2 3 4 5 6 7 8 9 10 11 12 13 14

3 E K 7 – 4 4 – 0

N N N

C

V

Z

S

M

L

X

1

9

B

C

D

E

F

Z

Data position

Order code

Rated voltage 10 x Ur (N: numerical)

Standard

IEC - CEI

VDE

Other

Enclosure size / creepage distance

Small

Medium

Large

eXtra large

Terminal, top

Clamp, washer, nut

Other

Terminal, bottom

Washer, nut

NEMA metal clip, washer, nut

DIN metal clip, washer, nut

NEMA insulating clip, with arrester disconnector, washer, nut

DIN insulating clip, with arrester disconnector, washer, nut

Other

Powerto the

Siemens AktiengesellschaftSubject to change without prior notice Order-No. E50001-U113-A209-X-7600

Printed in GermanyDispo-Stelle 3000061D6048 TV/EK 101368 PA 09995.

Power Transmission andDistribution GroupHigh Voltage DivisionNonnendammallee 104D-13629 Berlin

http://www.siemens.de/arrester

Would you like to find out more?

If you would like to know moreabout the new surge arresters fromSiemens, simply contact us andwe will inform you in detail.

Tel. ++49 (30) – 386 2 30 75Fax ++49 (30) – 386 2 67 21E-mail arrester@siemens.de

Technical Data

Distribution systemsand switchgear

Applications

Max. continuous operating voltage Uc

Max. rated voltage Ur

Nominal discharge current InMax. high current impulse 4/10 µs

Long duration current impulse 2 ms

Max. energy absorption capacity

Line discharge class

Short-circuit current strength 0.2 s

Enclosure material

3EK7

36 kV

45 kV

10 kA

100 kA

300 A

4.5 kJ/kVr

1

20 kA

HTV silicone