1 Measurement Instrument EUT (Equipment Under Test) Power connections Touch (Leakage) Current Test Measurement Circuit Components Power supply Switching network Measurement Equipment Connections

2 120 V GND OPEN A A B B S2S2 S1S1 2-pole, 2-wire 15 amp non-polarized N 15 amp polarized Applicable EUT Plug Configurations 2-pole, 3-wire EQUIPMENT UNDER TEST (EUT) Load Power Supply 20 amp G N 15 amp G N L N Polarity reversing switch Grounded conductor switch MEASUREMENT INSTRUMENT Connection to grounded supply conductor Measurement Circuit for 120 Volt Equipment INSULATING TABLE UL101 Switching Network

3 120 V A A B B S2S2 S1S1 2-pole, 2-wire 15 amp non-polarized 20 amp G 15 amp G N polarized Applicable EUT Plug Configurations 2-pole, 3-wire EQUIPMENT UNDER TEST (EUT) Load S3S3 Optional transformer < 1% line voltage For 3-wire applications 120 V supply L N G IEC Measurement Circuit for 120 Volt Equipment MEASUREMENT INSTRUMENT

4 GND OPEN A A B B S2S2 S1S1 EQUIPMENT UNDER TEST (EUT) Load Power Supply Polarity reversing switch Line Switch Connection to grounded supply conductor Measurement circuit for 2- pole 208 or Volt equipment suitable for use on volt to ground circuit 208 or V L N L Applicable U.S. EUT Plug Configurations 15 amp 20 amp G 15 amp G 2-pole, 2-wire 2-pole, 3-wire INSULATING TABLE (U.S.Commercial / Industrial) (European 230/400 v residential) MEASUREMENT INSTRUMENT

5 S1S1 GND OPEN A A B B S2S2 Measurement circuit for 2- pole 208 and 240 volt equipment for connection only to 120 volts to ground circuits (120/208, 120/240) Applicable U.S. EUT Plug Configurations 15 amp 20 amp G 15 amp G 2-pole, 2-wire 208 or 240 V 120 V 2-pole, 3-wire EQUIPMENT UNDER TEST (EUT) Load L L N Polarity reversing switch Line Switch Connection to grounded supply conductor INSULATING TABLE Power Supply MEASUREMENT INSTRUMENT (U.S.Residential)

6 EQUIPMENT UNDER TEST (EUT) Load A A B B S2S2 20 amp N 15 amp N G N G 20 amp 3-pole, 3-wire3-pole, 4-wire Measurement circuit for single phase, 3- pole, 208 or 240 Volt Equipment Applicable U.S. EUT Plug Configurations 208 or 240 V 120 V S1S1 GND OPEN N G 30 amp N L L N Line and Neutral Switch Connection to grounded supply conductor INSULATING TABLE PowerSupply Polarity reversing switch MEASUREMENT INSTRUMENT (e.g., electric ranges, clothes dryers)

7 Touch (Leakage) Current Topics Definitions (UL 101, IEC 60990) Touch current paths Physiological effects of touch current (electric shock) Body impedance models and “safe” voltage limits Touch (Leakage) Current Test –Touch current instruments (meters) –Measurement circuits and procedures –Limits

8Limits Touch (Leakage) Current Test UL Recommendations Type of appliance Two-wire cord- and plug- connected appliance Indication in MIU 0.50 MIU Three-wire (including grounding conductor) cord- and plug- connected portable appliance 0.50 MIU Three-wire (including grounding conductor) cord- and plug- connected stationary or fixed appliance 0.75 MIU All70 mA rms (electric burn)

9 SUMMARY Definitions (UL 101, IEC 60990) Touch current paths Physiological effects of touch current (electric shock) Body impedance models and “safe” voltage limits Touch (Leakage) Current Test –Touch current instruments (meters) –Measurement circuits and procedures –Limits

10 Questions and Answers

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