1. Safety Precautions
This product is designed to be used by a person with specialized knowledge.
When operating the instrument, be sure to observe the cautionary notes given below to ensure correct and
safe use of the instrument. If you use the instrument in any way other than as instructed in this manual,
the instrument's protective measures may be impaired.
This manual is an essential part of the product; keep it a safe place for future reference.
YOKOGAWA is by no means liable for any damage resulting from use of the instrument in contradiction to
these cautionary notes.
The following safety symbols are used on the instrument and in this manual.
Danger! Handle with Care.
This symbol indicates that the operator must refer to an explanation in the user’s manual
in order to avoid risk of injury or death of personnel or damage to the tester.
WARNING
Indicates a hazard that may result in the loss of life or serious injury of the user unless
the described instruction is abided by.
CAUTION
Indicates a hazard that may result in an injury to the user and/or physical damage to
the product or other equipment unless the described instruction is abided by.
Note
Indicates information that is essential for handling the instrument or should be noted in order to
familiarize yourself with the instrument’s operating procedures and/or functions.
High-voltage Terminal
This symbol indicates a dangerous voltage level (terminals with voltages exceeding
1000 volts must be so marked). Never touch the terminals.
Alternating Current
This symbol indicates alternating current (AC).
Double Insulation
This symbol indicates double insulation.
■ Always observe the following instructions. Failure to do so may result in electric shock or
other dangers that may lead to serious injury or the loss of life.
WARNING
This instrument is a insulation resistance tester that can measure insulation resistance (AC voltage).
Do not use this instrument for other purpose.
Do not use the instrument if there is a problem with its physical appearance.
1. During Measurement of Insulation Resistance
• A high voltage is present at the probes. Do not touch the measured object or the earth or line terminal.
2. Immediately After Measurement of Insulation Resistance
• The probes or measured object may remain highly charged.
Do not touch them immediately after the completion of measurement.
3. During Measurement of AC Voltage
• Do not press the MEAS key while measuring the AC voltages.
• Voltage that exceeds the specified limit must not be applied to terminals.
4. Probe
• Use the probes supplied by Yokogawa with this tester.
• Do not use probes that have deteriorated or are defective.
• Remove the probes from the measured object before attaching/detaching the probes to/from the tester.
5. Insulation of Casing
• A puncture in the protective insulation may occur if there are any cracks or other damage in the casing as
a result of the instrument having been dropped or knocked against another object.
Do not use the instrument before taking the necessary remedial measures; ask the manufacturer to repair it.
6. The Measured Object
• Turn off the power to the measured object before you begin measuring insulation resistance.
• Avoid touching any electrified parts while using the tester in a location with live electricity.
Safety protectors such as rubber-insulated gloves should be worn to prevent electrical shock
when using the tester.
7. Operating Environment
• Do not operate the tester in an atmosphere where any flammable or explosive gas is present.
• Do not use the tester if there is condensation on it.
8. Do Not Remove the Casing or Disassemble
Do not open the case except when replacing batteries.
Only Yokogawa service personnel are authorized to remove the casing or disassemble or
modify the instrument.
Do not attempt to repair the instrument yourself, as doing so is extremely dangerous.
When the instrument needs an internal inspection or calibration,
contact Yokogawa or the dealer from whom you purchased the instrument.
CAUTION
• The instrument is for domestic use (Class B) and meets the electromagnetic compatibility requirements.
• To verify the instrument's functionality, contact the tip of the earth probe and the line probe and then
press the MEAS key.
Check that the resistance indication is 0 Ω. (Check that the instrument operates normally.)
If the indication is incorrect, it may lead to possible electrical shock or personal injury.
■ Measurement Categories
Measurement category of the MY10
WARNING
• This instrument is designed for measurement category III (CAT III).
• Do not use the instrument for measurements in location that fall under measurement category IV.
Measurement category of the Probes
Line probe (98001) With cap: 600 V CAT III
Without cap: 600 V CAT II
Earth probe (98002) 600 V CAT III
WARNING
A cap is provided on the tip of the line probe.
Use the line probe with the cap on for safety (safety standard: EN61010-031).
Measurement
category
O
(None, Other)
CAT II
CAT III
CAT IV
Circuits not connected to
a mains power source.
Appliances,
portable equipment, etc.
Distribution board,
circuit breaker, etc.
Overhead wire,
cable systems, etc.
Other circuits that are not directly connected
to MAINS.
For measurements performed on circuits
directly connected to the low-voltage installation.
For measurements performed
in the building installation.
For measurements performed
at the source of the low-voltage installation.
Description
Remarks
2. Measuring Functions and Additional Features
■ Measuring Functions
• Measuring the insulation resistance
• Measuring AC voltages (sine wave at 50/60 Hz)
■ Additional Features
• Discharge feature
The tester is designed to begin discharging when the MEAS key is turned off.
The ALARM LED turns off when discharging is complete.
• Battery check
This function verifies if the battery voltages are within the valid ranges.
(When the battery is checked, the pointer must be within the BATT mark.)
• Phosphorescent scale plate
The indicator window lights up according to the intensity of light.
• Locking the MEAS key
Pulling the MEAS key up allows for continuous measurement over a prolonged period of time.
3. Components and Their Functions
4. Protective
cover
fitting
1. Indicator window
3. BATT CHECK
key
2. MEAS
key
6. ALARM LED
Front view
Side view
Rear view
5. Zero adjustment
(screw)
7. Battery cover
setscrew
8. Battery
cover
9. Shoulder strap
guide
10. Earth terminal
11. Line terminal
1. Indicator window
2. MEAS key
3. BATT CHECK key
Verifies if the battery voltages are within
the valid ranges.
4. Protective cover fitting
5. Zero adjustment (screw)
6. ALARM LED
• Discharge feature (On → Off)
When lit, it indicates that a capacitive component
in the measured object remains electrified and
will light up even if measurement has been
completed.
It turns off when discharge is complete.
7. Battery cover setscrew
Undo to replace batteries.
8. Battery cover
9. Shoulder strap guide
The shoulder strap is passed through it.
10. Earth terminal
Connection for earth probe
11. Line terminal
Connection for line probe.
Note
GUARD function is not a standard function.
4. Before Measurement
WARNING
• Remove the probes from the measured object before attaching/detaching the probes to/from the tester.
• Make sure the MEAS key is off when attaching/detaching the probes to/from the tester.
1. Safety
• Read the handling precautions in this manual carefully.
• Make sure it is safe before starting measurement.
2. How to Read the Scale
• Read the value from the top-right of the scale.
3. Zero Adjustment
• Confirm that the pointer is at the center of the infinity sign (
);
if it is, do not press the MEAS key.
• If it is not, adjust the pointer to indicate the center of the infinity sign (
) with
the zero adjustment screw using a slotted screwdriver.
4. Battery Voltage Verification
• Press the BATT CHECK key to make sure the battery voltages are within the valid ranges.
(When the battery is checked, the pointer must be within the BATT mark.)
• If the batteries are low, replace them as specified in the battery replacement section of this manual.
5. Connecting the Probes
• Plug the earth probe into the earth terminal.
• Plug the line probe into the line terminal.
5. Measuring the Insulation Resistance
5.1 Before Connecting the Probes
WARNING
• Turn off the power to the measured object before connecting the probes or measuring insulation resistance.
• Electrical charges may be present in the cables attached to or metal of the electrical equipment being tested.
Verify that the equipment is free from electrical charges before connecting the testing terminals.
5.2 Connecting the Earth Probe
• Securely connect the earth probe to the measured object’s ground line
(if the measured object is not grounded, this process may be omitted).
5.3 Connecting the Line Probe
• Bring the line probe into contact with the measured object, and then press the MEAS key.
The pointer indicates the insulation resistance of the measured object.
Note
During measurement, exercise care to prevent the lead wire of the line probe from coming into contact with
the ground, floor or any other object.
Not observing this precaution may result in a failure to measure the correct insulation resistance.
5.4 After Measurement
WARNING
• Immediately after measurement, electrical charges resulting from the applied testing voltage may remain
present in the probes or measured object.
• The tester, therefore, is designed to automatically begin discharging electricity upon completion of
measurement. Verify that the ALARM LED turns off when discharging is complete.
User's
Manual
Model MY10
Insulation Resistance Tester
Thank you for purchasing our Insulation resistance tester.
This manual describes the specifications and handling precautions of the Insulation resistance tester.
Before using this product, thoroughly read this manual to understand how to use it properly.
- Model -
MY10-01, MY10-02, MY10-03, MY10-04, MY10-05
Contact information of Yokogawa offices worldwide is provided on the following sheet.
PIM 113-01Z2: Inquiries
List of worldwide contacts
IM MY10-E
8th Edition: Oct. 2017 (YMI)
Printed in China
B3
Store this manual in an easily accessible
place for quick reference
All Rights Reserved. Copyright ©
1999, Yokogawa M&C Corporation,
2015, Yokogawa Meters & Instruments Corporation,
2017, Yokogawa Test & Measurement Corporation
