www.epcos.com
EPCOS Product Brief 2018
Features
Compact size
Highly reliable fuse design
Fuse prevents reconnection
for high safety
According to UL 1449
Also available with third lead
for status display
High surge current capability
(Imax 10 kA, In up to 5 kA)
Applications
Home appliances
Power supplies
Inverters
Photovoltaic inverters
Drives
Lighting applications
Communication and data
systems
Smart meters
SIOV Metal Oxide Varistors
NT Series of ThermoFuse Varistors
2© EPCOS AG 2018For further information please contact our sales ofce.
SIOV Metal Oxide Varistors
NT Series of ThermoFuse Varistors
Introduction
The new NT series of ThermoFuse™ varistors consists of a disk varistor connected in series with an integrated ther-
mally coupled fuse designed to trip in the event of overheating due to the excessive overvoltage. In this event, the fuse
trips and disconnects the overheated varistor from the power circuit and thus prevents ames from developing. This
increases the reliability of the equipment to be protected. Thanks to their thermal resistance and ame-retardant de-
sign, ThermoFuse™ varistors meet UL 94 V-0 requirements, and are also listed as Type 4CA in UL 1449, 4th edition.
In addition to the two varistor terminal wires, the NT series features a monitor output lead that may be used to send
a status signal, for example, to an LED to indicate that the fuse has been activated.
The product range comprises types with 14 mm and 20 mm diameter disks. The ThermoFuse™ varistors in the
NT series are designed to absorb maximum surge currents with an 8/20 µs pulse of between 6 kA and 10 kA
at rated voltages of between 130 VRMS and 750 VRMS. They have a surge current capability of 10.000 A and a maxi-
mum energy absorption capacity of 480 J for 2 ms.
NT types are designed for use in a wide range of applications, which include home appliances, power supplies,
inverters for solar installations, drives and smart meters. They can also be used for the general protection of electri-
cal wiring and installations.
Typical applications Lead conguration
Symbols and terms
Symbol Term
Ctyp Typical capacitance
icCurrent at which vc,max is measured
imax Maximum surge current (also termed peak current)
InNominal discharge current to UL 1449
vc,max Maximum clamping voltage at specied current ic
VDC DC operating voltage
VRMS AC operating voltage, root-mean-square value
VVVaristor voltage
Wmax Maximum energy absorption
3
For further information please contact our sales ofce.© EPCOS AG 2018
NT14 Series, 2 Leads
Electrical specications and ordering codes
Maximum ratings (TA = 85 °C) Characteristics (TA = 25 °C) Dimensions
Ordering code 1) Type 1)
(untaped)
SIOV-
VRMS
V
VDC
V
imax
(8/20 μs)
1 time
A
In2)
(8/20 μs)
15 times
A
Wmax
(2 ms)
J
VV
(1 mA)
V
vc,max
(ic @ 50 A)
(8/20 μs)
V
Ctyp
(1 kHz)
pF
th
max.
mm
e1
±1
mm
B72214R2131K101 NT14K130E2K4 130 170 6000 3000 50 205 ±10% 340 880 9.0 2.6
B72214R2141K101 NT14K140E2K4 140 180 6000 3000 55 220 ±10% 360 820 9.0 2.7
B72214R2151K101 NT14K150E2K4 150 200 6000 3000 60 240 ±10% 395 750 9.0 2.8
B72214R2171K101 NT14K175E2K4 175 225 6000 3000 70 270 ±10% 455 670 9.0 2.8
B72214R2211K101 NT14K210E2K4 210 270 6000 3000 80 330 ±10% 545 580 9.5 2.9
B72214R2251K101 NT14K250E2K4 250 320 6000 3000 100 390 ±10% 650 490 9.5 3.1
B72214R2271K101 NT14K275E2K4 275 350 6000 3000 110 430 ±10% 710 440 9.5 3.2
B72214R2301K101 NT14K300E2K4 300 385 6000 3000 125 470 ±10% 775 400 11.0 3.3
B72214R2321K101 NT14K320E2K4 320 420 6000 3000 136 510 ±10% 840 370 11.0 3.5
B72214R2351K101 NT14K350E2K4 350 460 6000 3000 110 560 ±10% 910 340 11.0 3.7
B72214R2381K101 NT14K385E2K4 385 505 6000 3000 136 620 ±10% 1025 315 11.0 4.0
B72214R2421K101 NT14K420E2K4 420 560 6000 3000 136 680 ±10% 1120 290 11.0 4.2
B72214R2461K101 NT14K460E2K4 460 615 6000 3000 150 750 ±10% 1240 260 11.0 4.4
B72214R2511K101 NT14K510E2K4 510 670 6000 3000 165 820 ±10% 1355 240 12.0 4.5
B72214R2551K101 NT14K550E2K4 550 745 6000 3000 180 910 ±10% 1500 215 12.0 4.7
B72214R2621K101 NT14K625E2K4 625 825 6000 3000 200 1000 ±10% 1650 200 13.0 5.0
B72214R2681K101 NT14K680E2K4 680 895 6000 3000 220 1100 ±10% 1815 180 13.0 5.5
1) The ordering codes listed (B72214R****K101) are for straight versions (standard); Kinked versions are available upon request under ordering codes
B72214R****K501. The type designations for straight versions are NT14K***E2K4 and for kinked versions NT14K***E2S5K4.
2) Nominal discharge current In according to UL 1449, 4th edition.
Dimensional drawings for NT14 series, 2 leads
Straight version Kinked version
4
For further information please contact our sales ofce.© EPCOS AG 2018
NT14 Series, 3 Leads
Electrical specications and ordering codes
Maximum ratings (TA = 85 °C) Characteristics (TA = 25 °C) Dimensions
Ordering code 1) Type 1)
(untaped)
SIOV-
VRMS
V
VDC
V
imax
(8/20 μs)
1 time
A
In2)
(8/20 μs)
15 times
A
Wmax
(2 ms)
J
VV
(1 mA)
V
vc,max
(ic @ 50 A)
(8/20 μs)
V
Ctyp
(1 kHz)
pF
th
max.
mm
e1
±1
mm
B72214W2131K101 NT14K130E2 130 170 6000 3000 50 205 ±10% 340 880 9.0 2.6
B72214W2141K101 NT14K140E2 140 180 6000 3000 55 220 ±10% 360 820 9.0 2.7
B72214W2151K101 NT14K150E2 150 200 6000 3000 60 240 ±10% 395 750 9.0 2.8
B72214W2171K101 NT14K175E2 175 225 6000 3000 70 270 ±10% 455 670 9.0 2.8
B72214W2211K101 NT14K210E2 210 270 6000 3000 80 330 ±10% 545 580 9.5 2.9
B72214W2251K101 NT14K250E2 250 320 6000 3000 100 390 ±10% 650 490 9.5 3.1
B72214W2271K101 NT14K275E2 275 350 6000 3000 110 430 ±10% 710 440 9.5 3.2
B72214W2301K101 NT14K300E2 300 385 6000 3000 125 470 ±10% 775 400 11.0 3.3
B72214W2321K101 NT14K320E2 320 420 6000 3000 136 510 ±10% 840 370 11.0 3.5
B72214W2351K101 NT14K350E2 350 460 6000 3000 110 560 ±10% 910 340 11.0 3.7
B72214W2381K101 NT14K385E2 385 505 6000 3000 136 620 ±10% 1025 315 11.0 4.0
B72214W2421K101 NT14K420E2 420 560 6000 3000 136 680 ±10% 1120 290 11.0 4.2
B72214W2461K101 NT14K460E2 460 615 6000 3000 150 750 ±10% 1240 260 11.0 4.4
B72214W2511K101 NT14K510E2 510 670 6000 3000 165 820 ±10% 1355 240 12.0 4.5
B72214W2551K101 NT14K550E2 550 745 6000 3000 180 910 ±10% 1500 215 12.0 4.7
B72214W2621K101 NT14K625E2 625 825 6000 3000 200 1000 ±10% 1650 200 13.0 5.0
B72214W2681K101 NT14K680E2 680 895 6000 3000 220 1100 ±10% 1815 180 13.0 5.5
1) The ordering codes listed (B72214W****K101) are for straight versions (standard); Kinked versions are available upon request under ordering codes
B72214W****K501. The type designations for straight versions are NT14K***E2 and for kinked versions NT14K***E2S5.
2) Nominal discharge current In according to UL 1449, 4th edition.
Dimensional drawings for NT14 series, 3 leads
Straight version Kinked version
5© EPCOS AG 2018For further information please contact our sales ofce.
NT20 Series, 2 Leads
Electrical specications and ordering codes
Maximum ratings (TA = 85 °C) Characteristics (TA = 25 °C) Dimensions
Ordering code 1) Type 1)
(untaped)
SIOV-
VRMS
V
VDC
V
imax
(8/20 μs)
1 time
A
In2)
(8/20 μs)
15 times
A
Wmax
(2 ms)
J
VV
(1 mA)
V
vc,max
(ic @ 100 A)
(8/20 μs)
V
Ctyp
(1 kHz)
pF
th
max.
mm
e1
±1
mm
B72220R2131K101 NT20K130E2K4 130 170 10000 5000 100 205 ±10% 340 1850 9.0 2.6
B72220R2141K101 NT20K140E2K4 140 180 10000 5000 110 220 ±10% 360 1700 9.0 2.7
B72220R2151K101 NT20K150E2K4 150 200 10000 5000 120 240 ±10% 395 1550 9.0 2.8
B72220R2171K101 NT20K175E2K4 175 225 10000 5000 135 270 ±10% 455 1350 9.0 2.8
B72220R2211K101 NT20K210E2K4 210 270 10000 5000 160 330 ±10% 545 1100 9.5 2.9
B72220R2251K101 NT20K250E2K4 250 320 10000 5000 195 390 ±10% 650 940 9.5 3.1
B72220R2271K101 NT20K275E2K4 275 350 10000 5000 215 430 ±10% 710 850 9.5 3.2
B72220R2301K101 NT20K300E2K4 300 385 10000 5000 250 470 ±10% 775 780 11.0 3.3
B72220R2321K101 NT20K320E2K4 320 420 10000 5000 273 510 ±10% 840 720 11.0 3.5
B72220R2351K101 NT20K350E2K4 350 460 10000 5000 200 560 ±10% 910 660 11.0 3.7
B72220R2381K101 NT20K385E2K4 385 505 10000 5000 273 620 ±10% 1025 600 11.0 4.0
B72220R2421K101 NT20K420E2K4 420 560 10000 5000 273 680 ±10% 1120 550 11.0 4.2
B72220R2461K101 NT20K460E2K4 460 615 10000 5000 300 750 ±10% 1240 500 11.0 4.4
B72220R2511K101 NT20K510E2K4 510 670 10000 5000 325 820 ±10% 1355 460 12.0 4.5
B72220R2551K101 NT20K550E2K4 550 745 10000 5000 360 910 ±10% 1500 410 12.0 4.7
B72220R2621K101 NT20K625E2K4 625 825 10000 5000 400 1000 ±10% 1650 380 13.0 5.0
B72220R2681K101 NT20K680E2K4 680 895 10000 5000 440 1100 ±10% 1815 340 13.0 5.5
B72220R2751K101 NT20K750E2K4 750 1060 10000 3000 480 1200 ±10% 2000 250 13.0 6.0
1) The ordering codes listed (B72220R****K101) are for straight versions (standard); Kinked versions are available upon request under ordering codes
B72220R****K501. The type designations for straight versions are NT20K***E2K4 and for kinked versions NT20K***E2S5K4.
2) Nominal discharge current In according to UL 1449, 4th edition.
Dimensional drawings for NT20 series, 2 leads
Straight version Kinked version
© EPCOS AG · A TDK Group Company
Edition 05/2018 · Ordering No. EPC:62029-7600 · Printed in Germany · PB 05181.
Important information: Some parts of this publication contain statements about the suitability of our products for certain areas of application. These statements are based on
our knowledge of typical requirements that are often placed on our products. We expressly point out that these statements cannot be regarded as binding statements about the
suitability of our products for a particular customer application. It is incumbent on the customer to check and decide whether a product is suitable for use in a particular application.
This publication is only a brief product survey which may be changed from time to time. Our products are described in detail in our data sheets. The Important notes
(www.epcos.com/ImportantNotes) and the product-specic Cautions and warnings must be observed. All relevant information is available through our sales ofces.
Structure of ordering codes: The ordering code for one and the same product can be represented differently in data sheets, data books, other publications and the website of EPCOS, or in
order-related documents such as shipping notes, order conrmations and product labels. The varying representations of the ordering codes are due to different processes employed and
do not affect the specications of the respective products. Detailed information can be found on the Internet under www.epcos.com/orderingcodes.
NT20 Series, 3 Leads
Electrical specications and ordering codes
Maximum ratings (TA = 85 °C) Characteristics (TA = 25 °C) Dimensions
Ordering code 1) Type 1)
(untaped)
SIOV-
VRMS
V
VDC
V
imax
(8/20 μs)
1 time
A
In2)
(8/20 μs)
15 times
A
Wmax
(2 ms)
J
VV
(1 mA)
V
vc,max
(ic @ 100 A)
(8/20 μs)
V
Ctyp
(1 kHz)
pF
th
max.
mm
e1
±1
mm
B72220W2131K101 NT20K130E2 130 170 10000 5000 100 205 ±10% 340 1850 9.0 2.6
B72220W2141K101 NT20K140E2 140 180 10000 5000 110 220 ±10% 360 1700 9.0 2.7
B72220W2151K101 NT20K150E2 150 200 10000 5000 120 240 ±10% 395 1550 9.0 2.8
B72220W2171K101 NT20K175E2 175 225 10000 5000 135 270 ±10% 455 1350 9.0 2.8
B72220W2211K101 NT20K210E2 210 270 10000 5000 160 330 ±10% 545 1100 9.5 2.9
B72220W2251K101 NT20K250E2 250 320 10000 5000 195 390 ±10% 650 940 9.5 3.1
B72220W2271K101 NT20K275E2 275 350 10000 5000 215 430 ±10% 710 850 9.5 3.2
B72220W2301K101 NT20K300E2 300 385 10000 5000 250 470 ±10% 775 780 11.0 3.3
B72220W2321K101 NT20K320E2 320 420 10000 5000 273 510 ±10% 840 720 11.0 3.5
B72220W2351K101 NT20K350E2 350 460 10000 5000 200 560 ±10% 910 660 11.0 3.7
B72220W2381K101 NT20K385E2 385 505 10000 5000 273 620 ±10% 1025 600 11.0 4.0
B72220W2421K101 NT20K420E2 420 560 10000 5000 273 680 ±10% 1120 550 11.0 4.2
B72220W2461K101 NT20K460E2 460 615 10000 5000 300 750 ±10% 1240 500 11.0 4.4
B72220W2511K101 NT20K510E2 510 670 10000 5000 325 820 ±10% 1355 460 12.0 4.5
B72220W2551K101 NT20K550E2 550 745 10000 5000 360 910 ±10% 1500 410 12.0 4.7
B72220W2621K101 NT20K625E2 625 825 10000 5000 400 1000 ±10% 1650 380 13.0 5.0
B72220W2681K101 NT20K680E2 680 895 10000 5000 440 1100 ±10% 1815 340 13.0 5.5
B72220W2751K101 NT20K750E2 750 1060 10000 3000 480 1200 ±10% 2000 250 13.0 6.0
1) The ordering codes listed (B72220W****K101) are for straight versions (standard); Kinked versions are available upon request under ordering codes
B72220W****K501. The type designations for straight versions are NT20K***E2 and for kinked versions NT20K***E2S5.
2) Nominal discharge current In according to UL 1449, 4th edition.
Dimensional drawings for NT20 series, 3 leads
Straight version Kinked version
