Hioki ST5540 User manual

EN
Instruction Manual
ST5541
LEAK CURRENT HiTESTER
ST5540
July 2016 Revised edition 7
ST5540A981-07 16-07H

Contents
i
Contents
Measurement Flowchart.................................1
Introduction.....................................................2
Inspection.......................................................2
Checking the contents of the package...........2
Safety Notes...................................................3
Usage Notes...................................................5
Chapter 1 Overview 7
1.1 Instrument Overview ..................7
1.2 Features .....................................8
1.3 What is Leakage Current? .......10
1.4 Leakage Current Measurement
Complying with Standards .......11
1.5 Types of Leakage Current .......12
1.6 Types of Leakage Current
Measurement ...........................13
Chapter 2 Instrument Labels
and Screens 23
2.1 Instrument Labels and Functions
................................................. 24
2.2 Screen configuration outline ....27
2.3 About the Touch Panel ............30
Chapter 3 Setting
Preparations 31
3.1 Power switch, breaker ON/OFF 31
3.2 Connecting the Power Cord 3.....2
Connecting the instrument power cord ......32
Connecting the power cord of the
equipment under test ................................33
Making connections to terminals S10, S12
and S13 ....................................................35
3.3 Connecting equipment under
test to the instrument ...............36
Connect the terminal ................................. 36
3.4 Turning Power On and OFF .....38
Turning Power On ..................................... 38
Turning Power Off ..................................... 40
3.5 Pre-Test Inspection.................. 41
Checking measurement frequency ............ 43
Connection/VA check screen .................... 44
Chapter 4 Settings 47
4.1 Selecting a Network .................48
4.2 Selecting the Grounding Class of
Equipment Under Test .............49
Registering an Equipment Name/
Control Number........................................ 50
4.3 Selecting a Measurement Mode
(opens the measurement screen)
..................................................51
4.4 Setting the Measurement Range
(Auto/Hold) ...............................54
4.5 Setting the Filter .......................59
4.6 Setting the Allowable Value .....61
Turning lower limit values on and off for
specific leakage current measurements .. 63
4.7 Selecting the Type of Target
Current .....................................64
4.8 Changing the Measurement
Method (Auto/Manual) ..............67
Setting automatic measurement items ...... 68
Setting the measurement delay
(delay time) .............................................. 70
Setting the measuring time ........................ 73
Chapter 5 Measurement
Preparations 75
5.1 Connecting the Test Lead ........75
Using L2200 Test Lead ............................. 77
Using the 9195 Enclosure Probe
(for measuring enclosure leakage current) 77
1
2
3
4
5
ST5540A981-07

Contents
ii
Using Alligator Clips (when using two
or three test leads) .................................................78
Chapter 6 Measurements 79
6.1 Making manual measurements 79
6.2 Making automatic measurements
................................................. 82
6.3 Measurement examples ...........83
Earth leakage current measurement ......... 83
Touch current measurement ..................... 84
Patient leakage current measurement*
(Patient connection - Earth) ..................... 90
Patient leakage current measurement*
(external voltage on a SIP/SOP).............. 93
Patient leakage current measurement*
(external voltage on a specific F-type
applied part) ............................................. 95
Patient leakage current measurement*
(external voltage on metal accessible part
not protectively earthed) .......................... 97
Patient auxiliary current measurement* .... 99
Total patient leakage current measurement*
(Patient connection - Earth)................... 100
Free current measurement
(Enclosure - Enclosure) ......................... 101
6.4 Saving Measurement Data
(As required).......................... 102
Checking Saved Measurement Data ....... 104
Displaying Saved Measurement Data ..... 104
Selecting Saved Measurement Data ...... 105
Deleting Saved Data ............................... 105
6.5 Saving Measurement Conditions
(Panel Save Function)
(as required) ..........................106
6.6 Printing Measurement Data
(as required) ..........................108
Setting up and connecting a printer ......... 108
Chapter 7 Instrument System
Settings 115
System Screen Configuration .................. 116
7.1 Setting the Mode (To use the
instrument as a voltmeter) .....117
7.2 Panel Load(Loading Saved
Measurement Conditions)...... 120
7.3 Initializing the Instrument .......121
7.4 Setting the Display Language 123
7.5 Checking Fuses(During Earth
leakage current and protective
conductor current measurements)
................................................123
7.6 Self-Test .................................124
7.7 Power On Polarity Switching
(to keep equipment under test
on during polarity switching) .. 126
Connect the isolation transformer............ 126
Setting Power On Polarity Switching .......127
Relay check 2 .......................................... 128
7.8 Auto Measure Setting
(set instrument status) ........... 129
7.9 Setting Lower Limit Values (factor)
............................................... 130
7.10 Setting Indication Unit ............131
7.11 Setting Date and Time ...........132
7.12 Interface Setting
(For Communication and Printing)
................................................133
7.13 Setting the Beep Sound .........135
7.14 Setting the Backlight.............. 136
Chapter 8 Controlling the
Instrument From a
Computer
(RS-232C,
USB interface) 139
8.1 ST5540/ST5541 Remote Interface
Overview (USB connection) ...140
8.2 Connect and be sure to tighten
the screws on the connector.. 141
Installation and operation procedures .....143
Specifications of RS-232C....................... 144
Specifications of USB .............................. 144

Contents
iii
8.3 Setting Communication
Conditions on the HiTESTER 145
8.4 Command Message Description
................................................146
Message Format ......................................146
Output Queue and Input Buffer ................151
Event Registers ........................................152
8.5 Initialization Items ..................153
8.6 Message Reference ...............154
Common Messages .................................154
Messages Specific to the HiTESTER....... 154
8.7 Command Message Description
............................................... 162
Common Messages .................................163
Specific commands ..................................165
8.8 To Transfer All Saved Data to
a Computer ............................243
8.9 Troubleshooting .....................244
Chapter 9 External Control
245
9.1 Description of Signals............ 246
9.2 Connecting to the EXT I/O
Terminal................................. 247
9.3 Electrical Specifications .........249
9.4 Internal Circuit Configuration .250
9.5 Timing Chart ..........................251
Panel load function at EXT I/O start .........253
9.6 Example of Output Signal
Connection .............................254
Chapter 10 Specifications255
10.1 Basic Functions...................... 255
10.2 Auxiliary measurement functions*
............................................... 256
10.3 Measurement System ............256
10.4 Accuracy ................................258
Current Measurement Section .................258
Network Section ...................................... 259
10.5 Other Functions ......................261
10.6 System-related Functions ......263
10.7 User interface .........................264
10.8 EXT I/O ..................................264
10.9 Relay output for medical equipment
(only ST5540) .........................264
10.10 PC Interfaces....................... 265
10.11Printer ...................................265
10.12General Specifications ..........266
10.13Compliant standards............. 268
10.14Measurement Networks ........269
Network A (for Electrical Appliance
and Material Safety Law) ....................... 269
Network B1 (for JIS T 0601-1:1999) ........ 270
Network B2 (for IEC 60601-1:2005 3rd) .. 271
Network C (for IEC 60990) ...................... 272
Network D (for UL) .................................. 274
Network E (General-purpose 1) .............. 275
Network F (General-purpose 2) ............... 275
Network G (for IEC61010-1) .................... 276
Chapter 11 Maintenance
and Service 279
11.1 Cleaning and Storage ............279
11.2 Repair and Servicing...............280
11.3 Replacing Fuses ....................282
11.4 Instrument Disposal ...............283
Appendix A1
Appendix1Terminology.................... A1
Appendix2List of instrument status,
other test condition and special
test condition......................... A4
Appendix3List of default settings..... A7
Appendix4External Dimensions..... A29
6
7
8
9
10
11
Appendix
Index
5

Contents
iv
Index i

1
2
Be sure to read "Usage Notes" (p. 5) before measuring.
The flowchart does not show the detailed procedures but the rough workflow.
Measurement Flowchart
See "6.5 Saving Measurement Conditions (Panel Save Function) (as required)" (p. 106)
See "6.4 Saving Measurement Data (As required)" (p. 102)
See "3.5 Pre-Test Inspection" (p. 41)
See "Chapter 6 Measurements" (p. 79)
Manual : Free-run measurement
(Measurement conditions can be changed during ongoing measurements)
Automatic : Set measurement conditions and measuring time to perform automatic measurements.
See "6.6 Printing Measurement Data (as required)" (p. 108)
See "Connecting the power cord of the equipment under test"
(p. 33)
See "Connecting the instrument power cord" (p. 32)
See "5.1 Connecting the Test Lead" (p. 75)
See "3.1 Power switch, breaker ON/OFF" (p. 31)
See "3.4 Turning Power On and OFF" (p. 38)
See "3.1 Power switch, breaker ON/OFF" (p. 31)
See "3.4 Turning Power On and OFF" (p. 38)
Connect the power cord
Connect test leads
Pre-Operation Inspection
Measurements
After automatic measurement ends
See "Chapter 4 Settings" (p. 47)
Settings depend on measurement method (Manual or Automatic)
Manual measurement : Perform settings from (p. 48) to (p. 67)
Automatic measurement : Perform settings from (p. 48) to (p. 73)
Turn on the circuit breaker
Settings
Connecting equipment under test to the instrument
See "3.3 Connecting equipment under test to the instrument"
(p. 36)
Turn on the power switch of the HiTESTER
The actual connection procedure will vary with the power supply
of the equipment under test.
Disconnect test leads and equipment under test
Turn off breakers and instrument power

2
Thank you for purchasing the HIOKI Model "ST5540/ST5541 Leak Current HiTester". To obtain maximum
performance from the instrument, please read this manual first, and keep it handy for future reference.
When you receive the instrument, inspect it carefully to ensure that no damage occurred during shipping.
In particular, check the accessories and connectors. If damage is evident, or if it fails to operate according
to the specifications, contact your dealer or Hioki representative.
Introduction
Inspection
• Before using the instrument, make sure that the insulation on the test leads is
undamaged and that no bare conductors are improperly exposed. Using the
Model L2200 Test Lead in such conditions could cause an electric shock, so con-
tact your dealer or Hioki representative for replacements.
• Before using the instrument, make sure that the insulation on the power cords is
undamaged and that no bare conductors are improperly exposed. Using the
instrument in such conditions could cause an electric shock, so contact your
dealer or Hioki representative for replacements.
• Use the original packing materials when transporting the instrument, if possible.
Checking the contents of the package
"ST5540/ST5541 Leak Current HiTester".........1
Power cord (for main instrument)..................... 1
Power cord for equipment under test............... 2
(for [LINE IN])
Enclosure Probe............................................... 1
Spare fuse for main instrument........................ 1
(250 V F50 mAL)
L2200 Test Lead...........................................1set
(1 red, 1 black)
Test lead(red)................................................... 1
(only ST5540)
Instruction manual............................................ 1
CD-ROM .......................................................... 1
Confirm that these contents are provided.

3
2
This manual contains information and warnings essential for safe operation of the instrument and for
maintaining it in safe operating condition. Before using it, be sure to carefully read the following safety
precautions.
The following symbols in this manual indicate the relative importance of cautions and warnings.
Safety Notes
This instrument is designed to comply with IEC 61010 Safety Standards,
and has been thoroughly tested for safety prior to shipment. However, mis-
handling during use could result in injury or death, as well as damage to
the instrument. Using the instrument in a way not described in this manual
may negate the provided safety features.
Be certain that you understand the instructions and precautions in the
manual before use. We disclaim any responsibility for accidents or injuries
not resulting directly from instrument defects.
Safety Symbols
In the manual, the symbol indicates particularly important information that the user should read before
using the instrument.
The symbol printed on the instrument indicates that the user should refer to a corresponding topic in the
manual (marked with the symbol) before using the relevant function.
Indicates a fuse.
Indicates a grounding terminal.
Indicates AC (Alternating Current).
Indicates the ON side of the power switch.
Indicates the OFF side of the power switch.
Indicates that the product conforms to regulations set out by the EC Directive.
WEEE marking:
This symbol indicates that the electrical and electronic appliance is put on the EU market after August 13,
2005, and producers of the Member States are required to display it on the appliance under Article 11.2 of
Directive 2002/96/EC (WEEE).
Indicates that incorrect operation presents an extreme hazard that could result in serious injury or death
to the user.
Indicates that incorrect operation presents a significant hazard that could result in serious injury or death
to the user.
Indicates that incorrect operation presents a possibility of injury to the user or damage to the instrument.
Indicates advisory items related to performance or correct operation of the instrument.

4
Accuracy
We define measurement tolerances in terms of f.s. (full scale), rdg. (reading) and dgt. (digit) values, with
the following meanings:
This instrument complies with CAT II (300 V) safety requirements.
To ensure safe operation of measurement instruments, IEC 61010 establishes safety standards for vari-
ous electrical environments, categorized as CAT II to CAT IV, and called measurement categories.
Using a measurement instrument in an environment designated with a higher-numbered category than
that for which the instrument is rated could result in a severe accident, and must be carefully avoided.
Use of a measurement instrument that is not CAT-rated in CAT II to CAT IV measurement applications
could result in a severe accident, and must be carefully avoided.
Other Symbols
Indicates a prohibited action.
See Indicates the location of reference information.
*Indicates that descriptive information is provided below.
(Example)
Leakage current For information on text in italics, refer to "Appendix1 Terminology" (p. A1).
Indicates descriptions relating to the RS-232C only.
Indicates descriptions relating to the USB only.
USB
f.s. (maximum display
value): The maximum displayable value. This is usually the name of the currently selected range.
rdg. (reading or
displayed value): The value currently being measured and indicated on the measuring instrument.
dgt. (resolution): The smallest displayable unit on a digital measuring instrument , i.e., the input value that
causes the digital display to show a "1" as the least-significant digit.
Measurement categories
CAT II : Primary electrical circuits in equipment connected to an AC electrical outlet by a power cord (portable tools,
household appliances, etc.)
CAT II covers directly measuring electrical outlet receptacles.
CAT III : Prima ry electrical circuits o f heavy equipment (fixed installations) connected directly to the distribution panel,
and feeders from the distribution panel to outlets.
CAT IV : The circuit from the service drop to the service entrance, and to the power meter and primary overcurrent pro-
tection device (distribution panel).

5
2
Follow these precautions to ensure safe operation and to obtain the full benefits of the various functions.
Usage Notes
Avoid the following locations that could cause an accident or damage to the instru-
ment.
Exposed to direct sunlight
Exposed to high temperature Inthe presenceof corrosiveor explosive gases
Exposed to water, oil, other
chemicals, or solvents
Exposed to high humidity or
condensation
Exposed to strong electro-
magnetic fields
Near electromagnetic radia-
tors
Exposed to high levels of par-
ticulate dust
Near induction heating sys-
tems
(e.g., high-frequency induc-
tion heating systems and IH
cooking utensils)
Subject to vibration
Avoid obstructing the ventilation holes on the sides of the instrument, as it could
overheat and be damaged, or cause a fire.
If the instrument operates abnormally or displays an abnormal indication, turn off
the power switch immediately, and contact your dealer or Hioki representative.
Precautions before measurement
• Before turning on the instrument, confirm that the voltage of the power
source matches the voltage specification indicated on the instrument's
power connector ([AC IN]). (The voltage specification (100, 120, 220 or
240 V) ordered by the customer is marked with a black dot in the line
voltage column on the rear panel.)
Note that using the power supply with improper voltage may damage the
instrument and result in electrical hazards.
• To avoid electrical accidents and to maintain the safety specifications of
this instrument, connect the power cord provided only to a 3-contact
(two-conductor + ground) outlet.
Do not use excessive force on the touch panel, and do not use sharp objects that
could damage the touch screen.

6
Fuse
•Replace the fuse only with one of the specified characteristics and
voltage and current ratings. Using a non-specified fuse or shorting
the fuse holder may cause a life-threatening hazard.
Measurement terminal section : 250 V F50 mAL
•To avoid electric shock, turn off the power switch and disconnect
the power cord and test leads before replacing the fuse.
• Since a blown fuse cannot be repaired or replaced by the cus-
tomer, contact your dealer or nearest Hioki sales office.
Use the VA check function for power supply fuse and blown fuse
check function for measurement circuit fuse to check for blown
fuses.
Connection
• Always turn both devices OFF when connecting and disconnecting an inter-
face connector and test lead. Otherwise, an electric shock accident may
occur.
• To avoid damaging the power cord, grasp the plug, not the cord, when
unplugging it from the power outlet.
• To avoid breaking the test lead or enclosure probe, do not bend or pull them.
• When the power is turned off, do not apply voltage or current to the measure-
ment terminals. Doing so may damage the instrument.
• L (Line), N (Neutral) and G (Ground) are indicated on the terminal block of the
instrument, and the contacts of the power cord of the device to be measured
are denoted L, N and E (Earth). If the power cord does not include an earth
(E) line, connect only the L and N terminals.
For details regarding the terminal block, refer to "3.3 Connecting equipment
under test to the instrument" (p. 36).
Measurement
To avoid the risk of electric shock when test leads are connected to
the T1 - T3 terminals, do not touch the part of the test lead that is
beyond the finger barrier.
The terminals output high voltages in some measurement modes.
Do not touch any part of
the test lead beyond the
finger barrier

1.1 Instrument Overview
7
1
Chapter 1 Overview
To ensure the safe use of electrical products, it is necessary to conduct electrical safety tests such as
insulation resistance, withstand voltage, ground resistance, and leakage current.
Complying with laws and standards regarding medical electrical equipment as well as non-medical elec-
trical equipment, this instrument can be used to measure leakage current in all types of electrical prod-
ucts from computers to medical equipment. It consists of measurement networks that simulate the human
body and a high-frequency volt meter.
It is also capable of switching power supply polarities and making measurements under simulated single-
fault conditions in equipment under test.
To simplify leakage current testing, all test operations can be selected and run from a touch panel on the
display screen.
Overview Chapter 1
1.1 Instrument Overview
Applicable lines of business and product applications
Manufacturers of medical electrical equipment Type approval testing, shipment inspection
Dealers of medical electrical equipment Maintenance, inspection
Service technicians for medical electrical equipment
(authorized service technicians) Maintenance, inspection
Clinical engineers, hospitals Maintenance, inspection
Clinical engineering schools For educational purposes
Authorized electricians for operating rooms, ICUs,
and CCUs Isolation transformer inspection
Public organizations Type inspection
Manufacturers of general electrical equipment Type inspection, shipment inspection
Users of general electrical equipment Maintenance, inspection
General electrical equipment installers Maintenance, inspection
Service technicians for general electrical equipment Maintenance, inspection
Manufacturers of general electrical equipment parts Type inspection, shipment inspection
Manufacturers of power supply equipment Type inspection, shipment inspection
Manufacturers of electrical automobiles Type inspection, shipment inspection

1.2 Features
8
To test electrical equipment for leakage current, it is necessary to use a measurement network that simu-
lates the human body in compliance with applicable standards or laws.
The instrument includes the 8 measurement networks below.
The use of these networks enables instrument compliance with other standards.
Once a measurement network is selected, the instrument displays a leakage current measurement mode
corresponding to the applicable standard or law.
This function makes it possible to continue testing without shutting down the equipment under test when
polarities are changed, which shortens the duration of the test.
(Be sure to use an isolation transformer when using power on polarity switching.)
The instrument provides a rated current of 20 A and a rated voltage of 250 V.
1.2 Features
Wide range of measurement networks in compliance with standards
and laws
1. Network A :For compliance with Electrical
Appliance and MaterialSafety Law
2. Network B1 :For JIS T0601-1:1999
3. Network B2 :IEC 60601-1:2005 3rd
Complies with JIS T 0601-1:2012
4. Network C :For IEC60990
5. Network D :For UL
6. Network E :For general-purpose 1
7. Network F :For general-purpose 2
8. Network G :For IEC 61010-1
Leakage current measurement mode
1. Earth leakage current
2. Touch current (Enclosure - Earth)
3. Touch current (Enclosure - Enclosure)
4. Touch current (Enclosure - Line)
5. Patient auxiliary current
6. Patient leakage current (Patient connection - Earth)
7. Patient leakage current (external voltage on a SIP/SOP*)
8. Patient leakage current (external voltage on a specific F-type applied part)
9. Patient leakage current
(external voltage on metal accessible part not protectively earthed)
10. Total patient leakage current (Patient connection - Earth)
11. Total patient leakage current (external voltage on a SIP/SOP*)
12. Total patient leakage current (external voltage on a specific F-type applied part)
13. Total patient leakage current
(external voltage on metal accessible part not protectively earthed)
14. Free current (Enclosure - Enclosure)
15. Enclosure - Earth leakage current
16. Enclosure - Enclosure leakage current
17. Enclosure - Line leakage current
18. Patient leakage current I
19. Patient leakage current II
20. Patient leakage current III
*SIP(Signal Input Part)/SOP(Signal Output Part)
Power on polarity switching function
Rated current 20 A

1.2 Features
9
1
Chapter 1 Overview
The insutrument allows you to check for unintended blown fuses in networks.
Check for blown fuses before and after measurements to enable high-reliability measurements.
All operations are performed using the touch panel. The display shows operable keys and the interactive
system guides you through measurement procedures.
The RS-232C, EXT I/O and USB interfaces are provided as standard equipment to enable the easy
transfer of measurement data with a computer. The EXT I/O connector allows external control.
Connect the optional 9442 Printer to print out measurement data and saved measurement data.
The instrument is equipped with a function to monitor the power supply voltage and current of equipment
under test.
Function for checking for blown fuses
Ease of operation
Interfaces
Printing (with optional printer)
Monitor function

1.3 What is Leakage Current?
10
High voltage is present in an electrical appliance that uses a commercial power supply as its main power
source. Touching such equipment may expose a person to an electrical shock when current passes
through the body to ground. This electrical shock is the result of "leakage current" or "touch current." Nor-
mally, electrical equipment is grounded to protect against electrical shocks. Current regularly flows
through the grounding wire, but should an abnormality (due to faulty design or fault) occur in equipment,
the resulting electrical shock may cause serious personal injury and sometimes lead to the death of the
victim. For this reason, leakage current measurements including single-fault conditions*1 are strictly regu-
lated.
Leakage current measurements performed according to the applicable standard makes it possible to ver-
ify the safety of equipment.
*1What is a single-fault condition?
This refers to when equipment has a fault in a safety protection measure, or a fault that may result in a
hazardous condition.
Leakage current testing includes the following three single-fault conditions.
1. Disconnected grounding wire (not applicable in current tests of leakage current)
2. One wire in the power cord is disconnected (neutral power supply wire)
3. External equipment damage*2
(patient leakage current II and patient leakage current III)
*2 In JIS T0601-1:1999 classified as a single-fault condition.
Not a single-fault condition, the instrument is capable of switching polarity during measurements and
retaining a recording of the phase with the highest leakage current.
1.3 What is Leakage Current?

1.4 Leakage Current Measurement Complying with Standards
11
1
Chapter 1 Overview
Electrical safety standards and laws are enacted for electrical products according to fields of application.
Each standard and law specifies a circuit network for simulating the human body, and prescribes network
performance, as well as measuring locations, type (e.g., AC, DC) of current to be measured, allowable
values, and other characteristics.
Listed below are various standards that require leakage current measurement.
1.4 Leakage Current Measurement
Complying with Standards
Standards requiring leakage current measurement
(Refer to the User's Guide for information on other standards.)
Electrical equipment
IEC 60065:2001 +A1:2005 Audio, video, and similar electronic apparatus - Safety
requirements
IEC60335-1:2010 Safety of household and similar electrical appliances.
- Part 1: General requirements
IEC 60950-1:2005 Safety of information technology equipment
IEC 60990:1999 Methods of measuring touch current and protective conduc-
tor current
UL2231-1, UL2231-2 Personnel Protection Systems for EV
Electric measuring instruments
IEC 61010-1:2010 Safety requirements for electrical equipment used in mea- surements, control and laboratories
Current measurement circuits for testing in damp conditions
Medical electrical equipment
JIS T 0601-1:1999
JIS T 0601-1:2012 Medical electrical equipment-Part1:General requirements for basic safety and essential performace
IEC 60601-1:2005 3rd Medical electrical equipment
Part 1: General requirements for safety

1.5 Types of Leakage Current
12
Leakage current can largely be classified as shown in the table below.
1.5 Types of Leakage Current
Types of
Leakage Current Overview Refer-
ence
Page
Earth leakage
current This refers to electric current that flows through a protective earth conductor to the ground. P.13
Touch current
Enclosure
leakage current
Touch current is electric current that flows through a person who touches an
ungrounded enclosed section of equipment. It does not include current that
flows to the human body in contact with an applied part.P.14
Patient leakage
current Patient leakage current flows through the body of someone connected to the
applied part.
Test items vary based on the type of applied part.P.15
Patient auxiliary
current Electric current that flows between applied parts and through a patient during
normal operation of medical equipment that is not intended to have any physi-
ological effect. P.15
Total patient
leakage current
When multiple applied parts are attached to a patient, the total leakage current
must be measured.
The sum of patient leakage current of applied parts is total patient leakage cur-
rent. P.19
Protective
conductor current Electric current that flows through a protective earth conductor (grounding wire) during normal operating conditions P.20

1.6 Types of Leakage Current Measurement
13
1
Chapter 1 Overview
Class-II equipment does not require the measurement of Earth leakage current since it has no protective
earth conductor.
Earth leakage current is measured by inserting a resistance equivalent to the human body in the protec-
tive earth conductor. Using a clamp (Clamp On HiTester) for measuring current does not satisfy the stan-
dard.
1.6 Types of Leakage Current Measurement
Earth leakage current measurement

1.6 Types of Leakage Current Measurement
14
Class-I equipment does not require the measurement of enclosure leakage current since metal enclo-
sures must be grounded for electrical protection. However, when the protective earth conductor becomes
disconnected (single fault), the enclosure is no longer grounded for protection and must be measured.
For Class-II equipment, all enclosures are ungrounded for electrical protection and must be tested.
Ungrounded equipment are often made of plastics and other insulated materials. Since leakage current
flows through the human body, the standard stipulates that a probe is applied to metal foil the size of a
hand pressed against the insulated material. Use the 9195 enclosure probe supplied with the instrument
for measurements involving this instrument.
There are two paths for touch current to flow: "enclosure human body earth" and "enclosure 
human body enclosure." Note that for "enclosure human body enclosure" to occur a person
must touch two electrically isolated (separate) enclosure sections not two sections on the same enclo-
sure.
Touch current measurement