Electronic Components & Devices

Safety standard

A capacitor that is used in an AC primary circuit for electromagnetic interference suppression is required to be compliant with the safety standards of the countries concerned.

  1. (1) When using a capacitor in an AC primary circuit for electromagnetic interference suppression, select capacitors that are certified under the safety standard.
  2. (2) Select a capacitor from a subclass required for the equipment in which it is to be used. The safety standards classify the subclasses based on the voltage-proof test and impulse voltage test.

Safety standards

Generally, the electric equipment that is used with AC power supply may stay plugged in. Therefore, a capacitor for electromagnetic interference suppression used between the lines or between the line and earth line may be subjected to severe conditions such as surge voltage from a lightning strike along with constantly applied AC voltage.
Moreover, from a safety perspective, when using a capacitor it is necessary to consider that capacitor failure can result in electric shock or fire.
To comply with safety regulations, select safety standard certified capacitors certified by the following certification bodies and under the following safety standards.

Major certification bodies and safety standards

Country Certification body Recognized
Applicable standards
U.S.A. UL UL1414
Canada CSA CSA C22.2
U.K. BSI EN 132400/IEC 60384-14
Germany VDE
Switzerland SEV
Sweden SEMKO
Finland FIMKO
Norway NEMKO
Denmark DEMKO

CSubclass of safety capacitor

Select a capacitor from suitable subclass satisfying the safety requirements of the equipment.

Capacitors of class X (inserted between lines of power supply circuit)

Subclass Peak impulse
voltage in service
Application Peak impulse
voltage Up applied
before endurance
(when CN≦1.0μF )
Voltage proof
X1 > 2500 V
≦ 4000 V
III High pulse
4000 V 4.3UR (d.c.)
UR: rated
X2 ≦ 2500 V II General
2500 V

Capacitors of class Y (inserted between a line of power supply circuit and the earth or enclosure)

Subclass Type of insulation
Range of rated
Peak impulse voltage
Up applied before
endurance test
Voltage proof
Y1 Double insulation or
≦ 500 V 8000 V 4000 V (a.c.)
Y2 Basic insulation or
≧150 V
≦500 V
When CN≦1.0μF
5000 V
When CN>1.0μF
UR + 1200 V (a.c.)
with a minimum of
1500 V (a.c.)
UR: rated voltage
Y4 Basic insulation or
< 150 V 2500 V 900 V (a.c.)

NOTE The details is referred to IEC 60384-14:2013. The voltage proof test is according to Test A.

Safety Application Guide for Multilayer Ceramic Chip Capacitors All Lists

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