1. Workshop on Safety Tests for Electrical Products Cairo, Egypt 3 – 4 December 2014 High voltage withstand test Dean Zekic Higher market inspector Croatian Ministry of economy

2. TAIEX Workshop on Safety Tests for Electrical Products; Cairo, Egypt, 3-4 December 2014. High voltage withstand test A dielectric strength test, dielectric withstand test, high potential test, HIPOT test A dielectric strength test, dielectric withstand test, high potential test, HIPOT test Electrical test performed on a component or product to determine the efectiveness of its insulation. Electrical test performed on a component or product to determine the efectiveness of its insulation. Making sure that consumers do not recive an electric shock because of breakdown of electrical insulation Making sure that consumers do not recive an electric shock because of breakdown of electrical insulation

3. TAIEX Workshop on Safety Tests for Electrical Products; Cairo, Egypt, 3-4 December 2014. High voltage withstand test High voltage source applied between a product’s current-carrying elements and shielding High voltage source applied between a product’s current-carrying elements and shielding Most important electrical safety test. Most important electrical safety test. Designing testDesigning test Production line testProduction line test Service testService test Routine maintenance testRoutine maintenance test Must be performed on every appliance before before placement on market Must be performed on every appliance before before placement on market

4. TAIEX Workshop on Safety Tests for Electrical Products; Cairo, Egypt, 3-4 December 2014. High voltage withstand test Verify quality of insulating material used in EE Verify quality of insulating material used in EE Verify correctly performing of electrical instalation. (spacings betwen energised elements, and grounding). Verify correctly performing of electrical instalation. (spacings betwen energised elements, and grounding). Manufacturing fault discover Manufacturing fault discover Performing standard maintenance measuring – predicting usable time of EE Performing standard maintenance measuring – predicting usable time of EE

5. TAIEX Workshop on Safety Tests for Electrical Products; Cairo, Egypt, 3-4 December 2014. High voltage withstand test Household appliance with impropper grounding Household appliance with impropper grounding Insulation breakdown – insulation fault between power line and appliance case Insulation breakdown – insulation fault between power line and appliance case Consumer bridging current ground path Consumer bridging current ground path → ELECTRIC SHOCK → ELECTRIC SHOCK

6. TAIEX Workshop on Safety Tests for Electrical Products; Cairo, Egypt, 3-4 December 2014. Type of HIPOT tests Regarding desired parameters of EE Regarding desired parameters of EE Dielectric breakdown test – measuring – estimating dielectric breakdown voltage in product design proces – destroying test – used in random sampleDielectric breakdown test – measuring – estimating dielectric breakdown voltage in product design proces – destroying test – used in random sample Dielectric voltage withstand Test – High voltage test - 100% producting line test – measuring amount of leakage current at voltage below breakdown voltageDielectric voltage withstand Test – High voltage test - 100% producting line test – measuring amount of leakage current at voltage below breakdown voltage Insulation resistance test – measuring quantifiable resistance value – DC testInsulation resistance test – measuring quantifiable resistance value – DC test

7. TAIEX Workshop on Safety Tests for Electrical Products; Cairo, Egypt, 3-4 December 2014. Electrical insulation model Insulation Resistance Test Touch (Leakage) Current Test Dielectric Withstand Test (Hi-pot) Basic Tests on Electrical Insulation

8. TAIEX Workshop on Safety Tests for Electrical Products; Cairo, Egypt, 3-4 December 2014. Type of HIPOT tests Regarding applyed voltage Regarding applyed voltage AC measuring voltageAC measuring voltage DC measuring voltageDC measuring voltage

9. TAIEX Workshop on Safety Tests for Electrical Products; Cairo, Egypt, 3-4 December 2014. Test performance Connecting high probe terminal of tester to power and neutral lines tied together, and low terminal to ground or exposed case of EE Connecting high probe terminal of tester to power and neutral lines tied together, and low terminal to ground or exposed case of EE Exposing connected appliance to high voltage – gradualy increasing (ramping test voltage) Exposing connected appliance to high voltage – gradualy increasing (ramping test voltage) Monitoring current flow for changes, comparing it with current waveforms nad amounts caracteristic ecspected to psysical state. Monitoring current flow for changes, comparing it with current waveforms nad amounts caracteristic ecspected to psysical state. After programed time, or after current exceeding presposed limit (breakdown) ending of measuring proces by turning off high voltage After programed time, or after current exceeding presposed limit (breakdown) ending of measuring proces by turning off high voltage Discharging od EE Discharging od EE

10. TAIEX Workshop on Safety Tests for Electrical Products; Cairo, Egypt, 3-4 December 2014. HIPOT tester Source of high voltage Source of high voltage Current meter Current meter A switching matrix A switching matrix

11. TAIEX Workshop on Safety Tests for Electrical Products; Cairo, Egypt, 3-4 December 2014. AC testing - advantages Presents operating tipe of transient voltage for most of EE Presents operating tipe of transient voltage for most of EE AC stresses the insulation oqualy in both polarities AC stresses the insulation oqualy in both polarities No waiting required after applying a test voltage No waiting required after applying a test voltage Not necessary to discharge the product after testing Not necessary to discharge the product after testing AC testing is more stressing for insulation - accelerates the breakdown in flawed material AC testing is more stressing for insulation - accelerates the breakdown in flawed material

12. TAIEX Workshop on Safety Tests for Electrical Products; Cairo, Egypt, 3-4 December 2014. AC testing - disadvantages Regarding capacitive nature of insulation of EE, reading of leakage current flow through insulation (real component)is not accurate. Regarding capacitive nature of insulation of EE, reading of leakage current flow through insulation (real component)is not accurate. Total measured current have real and reactive componentTotal measured current have real and reactive component For EE with large capacitance, leakage current increasing hard to detectFor EE with large capacitance, leakage current increasing hard to detect

13. TAIEX Workshop on Safety Tests for Electrical Products; Cairo, Egypt, 3-4 December 2014. DC testing - advantages Gradualy Increasing test voltage – non destructive testing- possibility to predict insulation breakdown Gradualy Increasing test voltage – non destructive testing- possibility to predict insulation breakdown

14. TAIEX Workshop on Safety Tests for Electrical Products; Cairo, Egypt, 3-4 December 2014. DC testing - advantages Only choice for testig particular components – capacitors and inverse voltage readings of diodes Only choice for testig particular components – capacitors and inverse voltage readings of diodes More accurate leakage current reading, regarding to absence of reactive component of current More accurate leakage current reading, regarding to absence of reactive component of current

15. TAIEX Workshop on Safety Tests for Electrical Products; Cairo, Egypt, 3-4 December 2014. DC testing - disadvantages Less practical for high capacitive devices since it is necessary to raise the voltage slowly Less practical for high capacitive devices since it is necessary to raise the voltage slowly Not considered as equivalent to AC test by most agencies Not considered as equivalent to AC test by most agencies Stresses insulation in one polarity only Stresses insulation in one polarity only

16. TAIEX Workshop on Safety Tests for Electrical Products; Cairo, Egypt, 3-4 December 2014. DC testing – insulation resistance Testing has four phases: Testing has four phases: ChargeCharge DwellDwell MeasureMeasure DischargeDischarge Dielectric adsorbtion current Dielectric adsorbtion current Charging current Charging current Leakage current Leakage current

17. Testing – caracteristic demands for measuring equipment Small changes in line voltage significally affects output voltage Small changes in line voltage significally affects output voltage Drop in output voltage regarding current flow through internal resistance of tester Drop in output voltage regarding current flow through internal resistance of tester Output voltage dropping below level – possibility of passing false productOutput voltage dropping below level – possibility of passing false product Modern testers monitoring output voltage and compensating eventual fluctuations – ensuring correct level of output voltageModern testers monitoring output voltage and compensating eventual fluctuations – ensuring correct level of output voltage

18. TAIEX Workshop on Safety Tests for Electrical Products; Cairo, Egypt, 3-4 December 2014. Testing – caracteristic demands for measuring equipment Distortion of output AC voltage (spike or high frequency transient) produced by the tester in proces of increasing voltage from zero to test voltage Distortion of output AC voltage (spike or high frequency transient) produced by the tester in proces of increasing voltage from zero to test voltage Problem eliminated by electronically controling the voltage and maintaining an undistorted waveform of output voltage during increasing voltage procesProblem eliminated by electronically controling the voltage and maintaining an undistorted waveform of output voltage during increasing voltage proces

19. TAIEX Workshop on Safety Tests for Electrical Products; Cairo, Egypt, 3-4 December 2014. Testing – caracteristic demands for measuring equipment Min/Max current detection – Low/high current limits Min/Max current detection – Low/high current limits Max current limit for succesiful Hipot test – shutting down hipot testerMax current limit for succesiful Hipot test – shutting down hipot tester Min current limit for detecting fault fixture or cable connectionMin current limit for detecting fault fixture or cable connection

20. TAIEX Workshop on Safety Tests for Electrical Products; Cairo, Egypt, 3-4 December 2014. Hipot test shortcomings For some EE switches or relays cannot be closed manually (double pole relays, electronic switches)– Hipot tester cannot energise all the current carrying elements For some EE switches or relays cannot be closed manually (double pole relays, electronic switches)– Hipot tester cannot energise all the current carrying elements Performing HOT HIPOT procedurePerforming HOT HIPOT procedure

21. TAIEX Workshop on Safety Tests for Electrical Products; Cairo, Egypt, 3-4 December 2014. electric strength EN 60335 -1:2002+A2 At operating temperature, electric strength shall be adequate. At operating temperature, electric strength shall be adequate. test voltage is applied between live parts and accessible parts with a voltage having a frequency of 50 Hz or 60 Hz for 1 min, and value given in tabletest voltage is applied between live parts and accessible parts with a voltage having a frequency of 50 Hz or 60 Hz for 1 min, and value given in table No breakdown shall occur during the testNo breakdown shall occur during the test

22. TAIEX Workshop on Safety Tests for Electrical Products; Cairo, Egypt, 3-4 December 2014. electric strength

23. TAIEX Workshop on Safety Tests for Electrical Products; Cairo, Egypt, 3-4 December 2014. CEI IETA laboratory measurement

24. TAIEX Workshop on Safety Tests for Electrical Products; Cairo, Egypt, 3-4 December 2014. CEI IETA laboratory measurement

25. TAIEX Workshop on Safety Tests for Electrical Products; Cairo, Egypt, 3-4 December 2014. CEI IETA laboratory measurement

26. TAIEX Workshop on Safety Tests for Electrical Products; Cairo, Egypt, 3-4 December 2014. CEI IETA laboratory measurement

27. Thank you for your attention! Dean Zekić, dipl. ing. el High market inspector Republic of Croatia Inspection directorate in economy Sector for market inspection Regional unit – Service inspection in Split Mob:00385 99 266 3104 Dean.zekic@mingo.hr