1. Touch (Leakage) Current
Hazard Based Safety Engineering - Touch (Leakage) Current

2. Touch (Leakage) Current
Overall Session Objectives:
1. To understand the rationale for the Touch (leakage) Current Test, instrumentation, connections, test procedures and limits
2. To understand limitations of test and alternative approaches

3. Touch (Leakage) Current
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
Notes:___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

4. Touch (Leakage) Current
DEFINITIONS
LEAKAGE CURRENT (UL ): Electric current which flows through a person upon contact, between accessible parts of an appliance and (1) ground, or (2) other accessible parts of the appliance
TOUCH CURRENT (IEC 60990): Electric current through a human body or an animal body when it touches one or more accessible parts of an installation or of equipment.
Notes:___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

5. Touch (Leakage) Current Paths
Accessible metal
Ungrounded
Conductor L +
Touch current
Load V S
Load _
Grounded
Conductor N
Return
Path
Electrical insulation System
Grounding
(protective earthing)
Conductor G ?
Notes:___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

6. Touch (Leakage) Current
Touch Current Paths
Touch (Leakage) Current
Example: Ungrounded 2 wire Cord and Plug-Connected Appliances
To Electrical Supply
Load
Load
Electrical Insulation
System
touchable metal
Notes:___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

7. Touch (Leakage) Current
radio
Can opener TV
Toaster oven
blender
Coffee
maker
iron
Examples of 2-wire Non-Grounded Appliances
Notes:___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

8. Touch (Leakage) Current
Touch Current Paths
Return Paths-1
Ungrounded
Conductor
Touchable metal L
Ungrounded
2 wire appliance
Touchable
metal +
Load V S
Load _
Grounded
appliance
Grounded
Conductor N G
Electrical insulation System
Grounding
(protective earthing)
Conductor
Touchable Metal
of Grounded Appliances G
Notes:___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
Equipment Grounding Conductor
(protective earthing conductor)
Touch Current

9. Touch (Leakage) Current
microwave
radio
Coffee
maker
range
Can opener TV
Toaster oven
refrigerator
blender
dishwasher
iron
Examples of 2-wire Non-Grounded Appliances
Examples of 3-wire Grounded Appliances
Notes:___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

10. Touch (Leakage) Current
Touch Current Paths
Return Paths-2
Ungrounded
Conductor
Touchable metal L
Ungrounded
2 wire appliance
Touchable
metal +
Load V S
Load _
Plumbing
Fixtures
Grounded
Conductor N G
Electrical insulation System
Grounding
(protective earthing)
Conductor
Construction Grounds G
Notes:___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
Touch Current
Metallic Piping System
Bonding connection
to water pipe

11. Touch (Leakage) Current
microwave
radio
Coffee
maker
Sink
Can opener
range TV
Toaster oven
refrigerator
blender
dishwasher
iron
Baseboard heating
Examples of 2-wire Non-Grounded Appliances
Examples of 3-wire Grounded Appliances
Examples of Construction Grounds
Notes:___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

12. Touch (Leakage) Current
Touch Current Paths
Return Paths-3
Ungrounded
Conductor
Touchable metal L
Ungrounded
2 wire appliance +
Load V S
Load _
Grounded
Conductor N G
Electrical insulation System
Grounding
(protective earthing)
Conductor
Pathway through earth
Notes:___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
Soil
Touch Current

13. Touch (Leakage) Current
Touch Current Paths
Touch (Leakage) Current
Example: Three - Wire Grounded Cord and Plug Connected product
Ungrounded
Conductor
Touchable metal L +
Load V S
Load _
Grounded
Conductor N G
Electrical
insulation
System
Grounding
(protective earthing)
Conductor
Potential Touch Current
Notes:___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

14. Touch (Leakage) Current
Touch Current Paths
Touch (Leakage) Current
Touchable metal
Load
Electrical
insulation
System L N G + _ V S
Ungrounded
Conductor
Grounded
Grounding
(protective earthing)
Example: Three - Wire Grounded Cord and Plug Connected product
Notes:___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

15. Touch (Leakage) Current
Example: Three - Wire Grounded Cord and Plug Connected product
Connection to Ungrounded Receptacle
Ungrounded
Conductor
Touchable metal L + V S
Load _
Grounded
metal
Grounded
Conductor
3 to 2 adapter N
Open circuit or high
impedance (fault) G
Grounding
(protective earthing)
Conductor
Electrical
insulation
System OR
2-wire
receptacle
(normal- old construction)
Notes:___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
Touch Current

16. Touch (Leakage) Current
Touch Current Paths-4
Touch (Leakage) Current
Touch Current From Simultaneously Touchable Parts of same product
Ungrounded
Conductor
touchable metal L +
Load
Load Z V S _
Grounded
Conductor N G
Grounding
(protective earthing)
Conductor
Touch Current
Notes:___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

17. Touch (Leakage) Current
Touch (Leakage) Current Topics
Definitions (UL 101, IEC 60990)
Touch current paths
Physiological effects of touch current (electric shock)
Notes:___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

18. Touch (Leakage) Current
Physiological Effects of Touch Current
(sinusoidal, rms, 60 Hz)
Perception (microamperes to 0.5 mA)
Startle reaction (> 0.5 mA)
Muscle tetanization (inability to let go) (> 5 mA)
Ventricular fibrillation (> 50 mA)
Electrical burns (> 70 mA)
Notes:___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
V10-001

19. Touch (Leakage) Current
Effects of Frequency on Electric Shock Thresholds
and Limits for Continuous AC current 10 3
IEC Threshold UL Limit
Ventricular Fibrillation 10 2
0.716
I = f
(see note 3)
f > 70 Hz 35 2
Let-Go 20
Body Current (rms mA)
I ~ f
f > 1 kHz 10 5
Startle Reaction 1
1. threshold/limit = 2 mA at 0 Hz (dc) 1
2. In the case of let-go, IEC
curve represents average value
0.5
3. respiratory arrest observed in dogs at 20, 30, and 40 mA
Notes:___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ 10 -1 10 2 10 3 10 4 5 10 6 10 10
Frequency (Hz)

20. Touch (Leakage) Current
Other Touch Current Variables
Waveshape*
Duration*
Current Density
Pathway through body
(skin contact location)
Notes:___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
* See Special Situations for Touch Current Measurements
V10-015

21. Touch (Leakage) Current
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
Notes:___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

22. Touch (Leakage) Current
Determining Touch Current
Voltage Source Z S + Z B I B V s _ V s I B
= body current I B = V s Z S Z B
= source open circuit voltage + Z S
= source impedance ( f ,
.....) Z B V S = Z S ,
Notes:___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ Z B
= body impedance

23. Touch (Leakage) Current
Five Component Body Impedance Model
Impedance representing one skin-electrode contact C 1 R 1 R 3
Internal body impedance (less the skin)
Impedance representing other skin-electrode contact C R 2 2
Notes:___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

24. Touch (Leakage) Current
Effect of Current Pathway on Internal Body Impedance
Internal Body Impedance (R3)
(typical adult)
Elbow- 200 ohms
Torso- 100 ohms
Wrist- 300 ohms
Knee- 150 ohms
Ankle- 350 ohms
CLASS EXERCISE:
What is the internal body impedance:
Hand to hand? _________ohms
One hand to both feet? ________ohms
Both hands to both feet? ______ ohms
Notes:___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

25. Touch (Leakage) Current
Simplified Body Impedance Models
3-component model for dry-moist contact and low touch voltage
Combination two large area skin contacts
Conservative model for low skin impedance (e.g., wet contact, high voltages, and/or high frequency)
0.22 Microfarad
1500 ohms
500 ohms
500 ohms
Notes:___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
Internal
body
impedance

26. Touch (Leakage) Current
Combined Effects of Frequency on Body Impedance and Electric Shock Thresholds Z
Body Impedance
Frequency
in Hertz 10
100
1000
10,000 I
Body Current Threshold for Let-Go
Frequency
in Hertz 10
100
1000
10,000
Applied Voltage Threshold For Let-Go
E = I x Z
Notes:___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
Frequency
in Hertz 10
100
1000
10,000

27. Touch (Leakage) Current
Examples of "Safe" Voltage Criteria
(Check the specific end-product standard)
Let-go and fibrillation, dry locations (UL, NEC)
 30 V AC rms (< 100 Hz)  60 V DC
Let-go and fibrillation, wet locations, not including immersion (UL, NEC)
 15 V AC rms (< 100 Hz)  30 V DC
Immersion conditions
Generally no “safe” voltages
Dry locations where startle reaction cannot be tolerated (UL)
 42.4 V peak (< 100 Hz) (including dc)
IEC SELV circuits:
normal conditions and single fault conditions for time > 0.2 sec
 42.4 V peak (< 100 Hz)  60 V DC
Notes:___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
single fault conditions for time < 0.2 sec
 71 V peak (< 100 Hz)  120 V DC

28. Touch (Leakage) Current
Electrical Insulation: Basic Equipment Safeguard Against Electric Shock Zs ZI ZB + IT Vs IS _ Vs
= source voltage ZI
= insulation impedance
IS = available source current Zs
= source impedance ZB
= body impedance IT
= Touch current
Notes:___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
VS exceeds “safe” voltage AND
Hazardous voltage and current source:
IS = VS / Zs exceeds “safe” available current

29. Touch (Leakage) Current
Basic Tests on Electrical Insulation
Electrical insulation model
Touch (Leakage) Current Test
Insulation Resistance Test
Dielectric Withstand Test (Hi-pot)
Notes:___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

30. Touch (Leakage) Current
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)
Notes:___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

31. Touch (Leakage) Current Test
Ungrounded
Conductor
Accessible metal
MEASUREMENT
INSTRUMENT L +
Load V S
Load _
Grounded
Conductor N
Electrical insulation System
Grounding
(protective earthing)
Conductor G
applies when source exceeds “safe” voltage levels
Notes:___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
represent body impedance as function of frequency
represent physiological effect as a function of frequency

32. Touch (Leakage) Current
Selection of Measurement Instrument
Instrument Specifications
SPECIFICATIONS FOR REACTION:
(0.5 mA rms 60 Hz)
ANSI C Average Responding System (ARS) (Still specified in most UL standards)
UL (Replaced ANSI C101)(Specified in some UL end product standards and most harmonized UL standards)
IEC – 1999
SPECIFICATIONS FOR LET-GO:
(3.5 mA rms, 5 mA rms 60 Hz)
IEC
SPECIFICATIONS FOR ELECTRICAL BURNS:
(70 mA rms) UL
Notes:___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
IEC

33. Touch (Leakage) Current
Measurement Instrument Specifications for Reaction
Average Responding System (ARS)
(ANSI C )
0.15 u F C1
1500 Ω R1 M
Ammeter
(average
responding)
(a) Input impedance (Z)
(intended to combine effect of frequency on body impedance and physiological response)
Notes:___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
(b) Meter type and location

34. Touch (Leakage) Current
Measurement Instrument Specifications for Reaction
Average Responding System (ARS)
(ANSI C )
IA = actual current to network IA
I1 = indicated current to network ( = V1/R1 rms for sinusoid) IA II / Z R1 =
Z = R1par C1
( kHz) V1 M VM I1
1500 Ω R1
0.15 uF C1
Voltmeter
(average
responding)
Indication (current) = 1.11 x VM (ave)/1500
(a) Input impedance (Z)
(combines effect of frequency on body impedance and physiological response)
(b) Meter type and location
= I 1 = V1 / R1
( rms for sinusoid)
Notes:___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
(c) Meter indication
Max 5%
indication of 0.75 mA
(d) Circuit frequency response ( 0 to 100 kHz)

35. Touch (Leakage) Current
Simpson Model 229 (ANSI C )
Notes:___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

36. Touch (Leakage) Current
Revised Measurement Instrument for Reaction 20 50 60
100
200
500
1000
2000
5000
10000
20000
50000
100000
200000
500000
Freq (Hz)
1998
1990
1986
1961
1857
1433
973
661
512
485
479
477
476
V1 / I1
500
499
498
495
480
405
284
162.9
68.3
34.4
17.21
6.89
3.45
1.722
0.680
0.345
V3 / I1
2.00
1.99
1.98
1.93
1.77
1.71
2.03
3.75
7.06
13.9
34.6
69.1
138
346
691
V1 / IIndicated
UL , IEC I1 V1 C1 R1 uF
0.22
1500 Ω
10 K Ω M V3
500 Ω R2 R3 F
0.022 u C2
Voltmeter
Rms reading
(UL101)
Revised body impedance model
Frequency sensitive network for reaction
(a) Input impedance (UL 101):
Z= V1 / I1 (20 Hz - 1 MHz)
Notes:___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
Peak reading
(IEC 60990)
(b) Transfer impedance (UL101):
Z= V3 / I1
(c) Meter indication (IIndicated):
= V3 / R2 = V3 / 500
(weighted mA -IEC 60990; MIU- ANSI C101)
(d) Input voltage per mA indication (IEC 60990):
V1 / I Indicated (mA)

37. Touch (Leakage) Current
Measurement Instrument for Let-Go 20 50 60
100
200
500
1000
2000
5000
10000
20000
50000
100000
200000
500000
Freq (Hz)
0.250
0.251
0.253
0.261
0.298
0.348
0.377
0.280
0.164
0.0860
0.0349
0.0175
V3 / V1
2.00
1.99
1.98
1.92
1.68
1.44
1.33
1.79
3.04
5.81
14.3
28.6
57.2
143
286
V1 / IIndicated
IEC C1 R1
0.22 uF
1500 Ω V1
10 K Ω C2 C3
500 Ω R2
0.0091 R3 uF
0.0062 uF M V3 R4
20 K Ω
Voltmeter
Body impedance model
Frequency sensitive network for Let-Go
Frequency sensitive network for reaction
Peak reading
(IEC 60990)
(a) Output voltage to input voltage ratio:
Notes:___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
V3 / V1 (20 Hz - 1 MHz)
(b) Meter indication (scale):
IIndicated = V3 (peak) / 500
Weighted mA
(c) Input voltage per milliampere indication:
V1 / Iindicated (mA)

38. Touch (Leakage) Current
Notes:___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

39. Touch (Leakage) Current
Touch (Leakage) Current Topics
Definitions (UL101, 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
Notes:___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

40. Touch (Leakage) Current
Touch (Leakage) Current Test Measurement Circuit Components
Power
supply
Power
connections
EUT (Equipment Under Test)
Measurement
Instrument
Switching
network
Notes:___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
Measurement Equipment Connections

41. Touch (Leakage) Current
Measurement Circuit for 120 Volt Equipment
Switching Network
UL101 L
Polarity reversing switch
EQUIPMENT UNDER TEST (EUT)
Load S2
Power
Supply
MEASUREMENT
INSTRUMENT A B
120 V S1 A B N
GND
OPEN
Grounded conductor
switch
INSULATING TABLE
Connection to grounded supply conductor
Applicable EUT Plug Configurations
15 amp
non-polarized N
15 amp
polarized
15 amp G N
20 amp G N
Notes:___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
2-pole, 2-wire
2-pole, 3-wire

42. Touch (Leakage) Current
Measurement Circuit for 120 Volt Equipment
IEC 60990
Optional
transformer L
EQUIPMENT UNDER TEST (EUT)
Load S2
MEASUREMENT
INSTRUMENT A B
120 V
supply
120 V S1 A B N
< 1% line
voltage G S3
For 3-wire applications
Applicable EUT Plug Configurations
15 amp
non-polarized N
15 amp
polarized
15 amp G
20 amp G
Notes:___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
2-pole, 2-wire
2-pole, 3-wire

43. Touch (Leakage) Current
Measurement circuit for 2- pole 208 or Volt equipment suitable for use on volt to ground circuit
(U.S.Commercial / Industrial) (European 230/400 v residential)
208 or V L N
Polarity reversing switch
EQUIPMENT UNDER TEST (EUT)
Load S1 S2
Power
Supply
MEASUREMENT
INSTRUMENT A B A B
GND
OPEN
Line Switch
INSULATING TABLE
Connection to grounded supply conductor
Applicable U.S. EUT Plug Configurations
15 amp G
20 amp G
15 amp
20 amp
Notes:___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
2-pole, 3-wire
2-pole, 2-wire

44. Touch (Leakage) Current
Measurement circuit for 2- pole 208 and 240 volt equipment
for connection only to 120 volts to ground circuits (120/208, 120/240)
(U.S.Residential) L
Polarity reversing switch
Power
Supply
EQUIPMENT UNDER TEST (EUT)
MEASUREMENT
INSTRUMENT S2
120 V A B N
208 or
240 V
Load
120 V S1 A B
GND
OPEN L
Line Switch
INSULATING TABLE
Connection to grounded supply conductor
Applicable U.S. EUT Plug Configurations G G
Notes:___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
15 amp
20 amp
15 amp
20 amp
2-pole, 3-wire
2-pole, 2-wire

45. Touch (Leakage) Current
Measurement circuit for single phase, 3- pole,
208 or 240 Volt Equipment
(e.g., electric ranges, clothes dryers) L
Polarity reversing switch
GND
OPEN
EQUIPMENT UNDER TEST (EUT)
Power
Supply
MEASUREMENT
INSTRUMENT S2
120 V A B N
208
or 240 V
Load S1
120 V A B L
INSULATING TABLE
Line and Neutral Switch
Connection to grounded supply conductor
Applicable U.S. EUT Plug Configurations G N G N G N N
Notes:___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ N
20 amp
30 amp
15 amp
20 amp
30 amp
3-pole, 3-wire
3-pole, 4-wire

46. Touch (Leakage) Current
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
Notes:___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

47. Touch (Leakage) Current
Touch (Leakage) Current Test
Limits
UL Recommendations
Type of appliance
Indication in MIU
Two-wire cord- and plug-
connected appliance
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
Notes:___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
All
70 mA rms (electric burn)

48. Touch (Leakage) Current
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
Notes:___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

49. Touch (Leakage) Current
Questions and Answers

50. Touch (Leakage) Current
Thank you very much !
- END -