Hioki CM4375 User manual

EN
EN
Instruction Manual
Sept.2018 Edition 1
CM4375A961-00 18-09H
CM4375
CM4376
AC/DC CLAMP METER
Instruction Manual
Sept.2018 Edition 1
CM4375A961-00 18-09H
CM4375
CM4376
AC/DC CLAMP METER

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Index
CM4375A961-00
Contents
Introduction.....................................................................................................1
Notation ..........................................................................................................2
Verifying Package Contents ...........................................................................4
Options (sold separately)................................................................................5
Usage Notes...................................................................................................6
1 Overview 11
1.1 Product Overview and Features......................................................... 11
1.2 Part Names ........................................................................................12
2 Making Measurements 13
2.1 Inspection Before Measurement ........................................................13
2.2 Current Measurement ........................................................................14
Manual Hold /Auto Hold...................................................................... 15
Filter Function.....................................................................................18
MAX value/MIN value/AVG value/PEAK value...................................19
Rush current (INRUSH)......................................................................20
2.3 Other Measurement Functions...........................................................21
2.4 Bluetooth®Communications (only for CM4376) ................................. 25

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Contents
2.5 Backlight /Auto Power Save (APS)..................................................... 30
2.6 Power-on Option Table....................................................................... 31
3 Specications 33
3.1 GeneralSpecications .......................................................................33
3.2 Inputspecications/Measurementspecications ...............................35
3.3 Accuracy Table ...................................................................................42
4 Repairs, Inspections, and Cleaning 57
4.1 Troubleshooting..................................................................................57
4.2 Error display .......................................................................................59
4.3 Insert/Replace Batteries.....................................................................60
4.4 Cleaning .............................................................................................61
Index 63
WarrantyCerticate

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1
Introduction
Thank you for purchasing the Hioki CM4375, CM4376 AC/DC Clamp Meter. To obtain maximum
performance from the instrument over the long term, be sure to read this manual carefully and
keep it handy for future reference.
Read the separate document “Operating Precautions” carefully before using the instrument.
Target audience
This manual has been written for use by individuals who use the product in question or who teach
others to do so. It is assumed that the reader possesses basic electrical knowledge (equivalent
to that of someone who graduated from the electrical program at a technical high school).
Trademark
•Bluetooth®is a registered trademark of Bluetooth SIG, Inc.(USA). The trademark is used by
HIOKI E.E. CORPORATION under license.
•Android, Google Play, and Google Chrome are trademarks of Google, Inc.
• IOS is a registered trademark of Cisco Systems, Inc. and/or its afliates in the United States
and certain other countries.
•iPhone, iPad, iPad miniTM, iPad Pro, and iPod touch are trademarks of Apple Inc.
•The App Store is a service mark of Apple Inc.
•Any other products and company names are generally either trade names, registered
trademarks or trademarks of respective companies.

2
Notation
Notation
Symbols afxed to the instrument
Indicates cautions and hazards. Refer to the "Usage Notes" (p.6) section of the instruction
manual and the included “Operating Precautions” for more information.
Indicates that the instrument may be connected to or disconnected from a live conductor.
Screen display
The instrument screen displays the alphanumeric characters as follows.
1 2 3 4 5 6 7 8 9 0
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
A different display is used in the case below.
: Wiring break detected

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Notation
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Accuracy
We dene measurement tolerances in terms of f.s. (full scale), rdg. (reading) and dgt. (digit) values with the
following meanings:
f.s. (maximum display value/range)
The maximum displayable value. This is usually the name of the currently selected range.
rdg. (displayed value)
The value currently being measured and displayed 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-signicant digit.

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Verifying Package Contents
Verifying Package Contents
Model CM4375 or CM4376
AC/DC Clamp Meter
Model L9207-10 Test Lead
9243 graber L4937 マグネットアダプ
タ
L4934 小ワニグチ
マグネ付ストラップ
L9207-10
DM4910 熱電対
DT4911TestLead
DT4912TestLead
L4930 接続ケーブル
L4931renketu
L4931 延長ケーブル
L4932(+9207-10cap)
L4933 コンタクトピン
L4935 ワニ口
L4936 バスバー
Model C0203 Carrying Case
LR03 Alkaline battery ×2
Instruction Manual*
Operating Precautions (0990A907)
Precautions Concerning Use of
Equipment that Emits Radio Waves (only
for model CM4376)
* Instruction manuals may also be available in other languages.
Please visit our website at http://www.hioki.com

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Options (sold separately)
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1
Options (sold separately)
C0203 Carrying Case
9243 graber L4937 マグネットアダプ
タ
L4934 小ワニグチ
マグネ付ストラップ
L9207-10
DM4910 熱電対
DT4911TestLead
DT4912TestLead
L4930 接続ケーブル
L4931renketu
L4931 延長ケーブル
L4932(+9207-10cap)
L4933 コンタクトピン
L4935 ワニ口
L4936 バスバー
9243 graber L4937 マグネットアダプ
タ
L4934 小ワニグチ
マグネ付ストラップ
L9207-10
DM4910 熱電対
DT4911TestLead
DT4912TestLead
L4930 接続ケーブル
L4931renketu
L4931 延長ケーブル
L4932(+9207-10cap)
L4933 コンタクトピン
L4935 ワニ口
L4936 バスバー
9243 graber L4937 マグネットアダプ
タ
L4934 小ワニグチ
マグネ付ストラップ
L9207-10
DM4910 熱電対
DT4911TestLead
DT4912TestLead
L4930 接続ケーブル
L4931renketu
L4931 延長ケーブル
L4932(+9207-10cap)
L4933 コンタクトピン
L4935 ワニ口
L4936 バスバー
9243 graber L4937 マグネットアダプ
タ
L4934 小ワニグチ
マグネ付ストラップ
L9207-10
DM4910 熱電対
DT4911TestLead
DT4912TestLead
L4930 接続ケーブル
L4931renketu
L4931 延長ケーブル
L4932(+9207-10cap)
L4933 コンタクトピン
L4935 ワニ口
L4936 バスバー
9243 graber L4937 マグネットアダプ
タ
L4934 小ワニグチ
マグネ付ストラップ
L9207-10
DM4910 熱電対
DT4911TestLead
DT4912TestLead
L4930 接続ケーブル
L4931renketu
L4931 延長ケーブル
L4932(+9207-10cap)
L4933 コンタクトピン
L4935 ワニ口
L4936 バスバー
9243 graber L4937 マグネットアダプ
タ
L4934 小ワニグチ
マグネ付ストラップ
L9207-10
DM4910 熱電対
DT4911TestLead
DT4912TestLead
L4930 接続ケーブル
L4931renketu
L4931 延長ケーブル
L4932(+9207-10cap)
L4933 コンタクトピン
L4935 ワニ口
L4936 バスバー
9243 graber L4937 マグネットアダプ
タ
L4934 小ワニグチ
マグネ付ストラップ
L9207-10
DM4910 熱電対
DT4911TestLead
DT4912TestLead
L4930 接続ケーブル
L4931renketu
L4931 延長ケーブル
L4932(+9207-10cap)
L4933 コンタクトピン
L4935 ワニ口
L4936 バスバー
9243 graber L4937 マグネットアダプ
タ
L4934 小ワニグチ
マグネ付ストラップ
L9207-10
DM4910 熱電対
DT4911TestLead
DT4912TestLead
L4930 接続ケーブル
L4931renketu
L4931 延長ケーブル
L4932(+9207-10cap)
L4933 コンタクトピン
L4935 ワニ口
L4936 バスバー
9243 graber L4937 マグネットアダプ
タ
L4934 小ワニグチ
マグネ付ストラップ
L9207-10
DM4910 熱電対
DT4911TestLead
DT4912TestLead
L4930 接続ケーブル
L4931renketu
L4931 延長ケーブル
L4932(+9207-10cap)
L4933 コンタクトピン
L4935 ワニ口
L4936 バスバー
9243 graber L4937 マグネットアダプ
タ
L4934 小ワニグチ
マグネ付ストラップ
L9207-10
DM4910 熱電対
DT4911TestLead
DT4912TestLead
L4930 接続ケーブル
L4931renketu
L4931 延長ケーブル
L4932(+9207-10cap)
L4933 コンタクトピン
L4935 ワニ口
L4936 バスバー
L4933 Contact Pin Set *6
L4934 Small Alligator Clip Set *5
L4935 Alligator Clip Set *2
9243 Grabber Clip *3
L4936 Bus Bar Clip Set *4
L4937 Magnetic Adapter Set *3
L4932 Test Pin Set *1
L9207-10 Test Lead *1
L4930 Connection Cable Set *2
(Length: 1.2 m)
L4931 Extension Cable Set *2
(Length: 1.5 m, with the coupling
connector)
9243 graber L4937 マグネットアダプ
タ
L4934 小ワニグチ
マグネ付ストラップ
L9207-10
DM4910 熱電対
DT4911TestLead
DT4912TestLead
L4930 接続ケーブル
L4931renketu
L4931 延長ケーブル
L4932(+9207-10cap)
L4933 コンタクトピン
L4935 ワニ口
L4936 バスバー
DT4910 Thermocouples (K)
L4938 Test Pin Set *7
L4939 Breaker Pin Set *4
9804 Magnetic Adapter *8
*1: CAT IV 600 V/ CAT III 1000 V/ CAT II 1000 V *5: CAT III 300 V/ CAT II 600 V
*2: CAT IV 600 V/ CAT III 1000 V *6: 33 V AC/ 70 V DC
*3: CAT III 1000 V *7: CAT III 600 V/ CAT II 600 V
*4: CAT III 600 V *8: CAT IV 1000 V

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Usage Notes
Usage Notes
Follow these precautions to ensure safe operation and to obtain the full benets of the various
functions. Read the separate document “Operating Precautions” carefully before using the
instrument. Ensure that your use of the product falls within the specications not only of the
instrument itself, but also of any accessories, options, batteries, and other equipment being
used.
DANGER
•To prevent an electric shock, do not touch any areas beyond the barrier
while the instrument is in use.
See: "1.2 Part Names" (p.12)
•The maximum measurement current varies with the frequency, and the
current that can be measured continuously is limited. Operating the
instrument at less than this limitation is referred to as derating. Do not
measure currents in excess of the derating curve. Doing so may result in
instrument damage or malfunction, a re, or burn due to sensor heating.
•To prevent an electric shock, conrm that the white portion (insulation layer)
inside the cable is not exposed. If a color inside the cable is exposed, do not
use the cable.

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Usage Notes
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WARNING
•Do not allow the instrument to get wet, and do not take measurements with
wet hands. This may cause an electric shock. (This precaution does not
apply to insulated conductors.)
•To prevent an electric shock, do not exceed the lower of the ratings shown
on the instrument and test leads.
CAUTION
Do not place any foreign object between the jaws or any insert foreign
object into the gap of the sensor head. Doing so may worsen the
performance of the sensor or the opening-closing operation of the
sensor head.
Avoid dropping or jarring the instrument, which could damage the jaw,
adversely affecting measurement.
Attach the clamp around only one conductor. If you clamp single-
phase (2-wire) or three-phase (3-wire) conductors together, the
instrument will not be able to make a measurement.

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Usage Notes
Test Lead
WARNING
To prevent an electric shock, when measuring the voltage of a power line use a
test lead that satises the following criteria:
•Conforms to safety standards IEC61010 or EN61010
•Measurement category III or IV
•Its rated voltage is higher than the voltage to be measured
The optional test leads provided for the instrument conform to the safety
standard EN61010. Use a test lead in accordance with its dened measurement
category and rated voltage.
•To prevent a short-circuit accident, be sure to use the test leads with the
sleeves attached when performing measurements in the CAT III and CAT IV
measurement categories.
•If the sleeves are removed during measurement, stop the measurement.
CAUTION
The cable is hardened in freezing temperatures. Do not bend or pull it to avoid tearing
its shield or cutting cable.

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Usage Notes
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Model L4937, 9804 Magnetic Adapter Set (optional)
DANGER
P ersons wearing electronic medical devices such as a pacemaker should not
use the Magnetic Adapter Set. Such persons should avoid even proximity to the
Magnetic Adapter Set, as it may be dangerous. Medical device operation could be
compromised, presenting a hazard to human life.
CAUTION
•Do not subject the Magnetic Adapter Set to mechanical shock, for example, due to
dropping it. Shock can cause it to be chipped or cracked.
•Do not use the Magnetic Adapter Set in locations where it may be exposed to
rainwater, dust, or condensation. In those conditions, the Magnetic Adapter Set
may be decomposed or deteriorated. The magnet adhesion may be diminished. In
such case, the instrument may not be hung in place and may fall.
•Do not bring the Magnetic Adapter Set near magnetic storage device such as
oppy disks, magnetic cards, pre-paid cards, or magnetized tickets. Doing so may
corrupt and may render them unusable. Furthermore, if the Magnetic Adapter
Set is brought near precision electronic equipment such as PCs, TV screens, or
electronic wrist watches, they may fail.

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Usage Notes

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1Overview
1.1 Product Overview and Features
Measurement function list
DC current/DC voltage, DC power
Capacitance, temperature
Continuity check, resistance, diode
AUTO AC/DC, AC voltage, DC
voltage, AC+DC voltage, frequency
AUTO AC/DC, AC current, DC
current, AC+DC current, frequency
This instrument is a clamp meter that can
perform true RMS measurement of current
simply by clamping it around a circuit. In
addition to current, it provides voltage
measurement, frequency measurement, rush
current measurement, resistance measurement,
diode measurement, capacitance measurement,
temperature measurement, and DC power
measurement.
Model CM4376 also provide Bluetooth®
communications functionality, allowing
measurement data to be monitored and logged
from a mobile device.
1 Overview

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Overview
1.2 Part Names
Front Rear
(CM4376)
7
9
5
1
2
8
12
3
11
4
10
6
1Operation grip
2Jaw open/closed mark
(The jaws are open if the mark is not
showing.)
3SHIFT key
(Selects function indicated in blue lettering.)
4Jaw
5Barrier
6Serial number (The serial number consists of
9 digits. The rst two (from the left) indicate
the year of manufacture, and the next two
indicate the month of manufacture.)
7Rotary switch
8HOLD key
9LCD
10 Battery cover
11 Operation keys
12 Measurement terminals

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2Making Measurements
2.1 Inspection Before Measurement
Check if there is any damage to the instrument occurred during storage or shipping and
verify that instrument operates normally before using it. If you nd any damage, contact your
authorized Hioki distributor or reseller.
Check item
The battery cover is closed and its screw has
been securely tightened.
There is no damage to the test lead
insulation, and neither the white sheathing nor
metal conductor inside the wire are exposed.
There is no foreign matter on the
measurement terminals. (p.12)
The instrument is neither damaged nor cracked.
The test leads are not broken.
OK
NO NONO
OK NO NO NO
1 Ωor less
No indicators are missing.
(All lit up)
2 Making Measurements

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Current Measurement
2.2 Current Measurement
e.g.: 3P4W (3-phase, 4-wire) circuit
breaker (AC current measurement)
AUTO
(AUTO AC/DC) (AC+DC A)(DC A)
(AC A)
3
Clamp the instrument around a conductor.Turn the rotary switch.
1
4
2
Press for 1 sec.
Zero adjustment
Frequency detection range of AC current
5.0 A or more
DC current polarity detection function
(p.31)
If the measured value is negative, the
buzzer will sound, and the display will turn
red (threshold: −10 A). Hz
(Frequency)
Be sure that the currents
direction points the arrow.

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Current Measurement
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Manual Hold /Auto Hold
Manual hold Auto hold
Measured value
retains. (Measured value stabilizes.)
Measured value automatically retains.
Clamp the instrument around a
conductor.
Pressing the HOLD key again cancels
the measured value hold function.
blinks.
Pressing the HOLD key for 1 sec. cancels the auto
hold function.
Press for 1 sec.
Disconnect

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Current Measurement
Auto hold conditions
Display value updates are stopped when the following two conditions are satised:
• When the measured value exceeds the threshold value described in the table in the next page. (voltage,
current). When the measured value is less than the threshold value described in the table in the next page.
(resistance, continuity, diode)
• When the range over which the measured value is uctuating stabilizes within the uctuation range
described in the table in the next page.
Start
End
Start
End
Start
End
Threshold
e.g.: 12.0 A
Auto hold
e.g.: 99.0 A
Auto hold
e.g.: 100.0 A
Measured
value
Fluctuation range
Time
Fluctuation range
Fluctuation range
Held measured value
Measurement
If the measured value falls below the threshold value (voltage, current) or exceeds the threshold value
(resistance, continuity, diode) after display value updates are stopped, the display value update is restarted.
Display value updates will stop if the two conditions are satised once again.