Hioki CM4375, CM4376 Instruction Manual

CM4375
CM4376

AC/DC CLAMP METER

Sept. 2018 Edition 1
CM4375A961-00 18-09H

Instruction Manual



EN

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

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2

3

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

CM4375A961-00

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Index

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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

ii

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.

1

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.

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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.

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

1 2 3 4 5 6 7 8 9 0

A different display is used in the case below.

: Wiring break detected

2

Notation

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.

1

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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3

Verifying Package Contents

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

Verifying Package Contents



Model CM4375 or CM4376



AC/DC Clamp Meter

Model L9207-10 Test Lead



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)

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

DM4910 熱電対

DT4911TestLead

DT4912TestLead

L4930 接続ケーブル

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

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

9243 graber

L4937 マグネットアダプ

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

L4937 マグネットアダプ
タ

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)

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

L4937 マグネットアダプ
タ

L4934 小ワニグチ

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

9243 graber

L4937 マグネットアダプ
タ

DM4910 熱電対

Options (sold separately)

L9207-10 Test Lead

L4930 Connection Cable Set
(Length: 1.2 m)

L4931 Extension Cable Set *
(Length: 1.5 m, with the coupling
connector)

DT4910 Thermocouples (K)

C0203 Carrying Case

*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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L4933 Contact Pin Set

L4934 Small Alligator Clip Set

L4935 Alligator Clip Set

9243 Grabber Clip

L4936 Bus Bar Clip Set

L4937 Magnetic Adapter Set

9804 Magnetic Adapter *

L4932 Test Pin Set

L4938 Test Pin Set

L4939 Breaker Pin Set

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*

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*

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*

4

*

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*

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*

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*

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*

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5

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.

6

Usage Notes

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.

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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

To prevent an electric shock, when measuring the voltage of a power line use a
test lead that satises the following criteria:

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.

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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WARNING

• Conforms to safety standards IEC61010 or EN61010

• Measurement category III or IV

• Its rated voltage is higher than the voltage to be measured

• 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

Model L4937, 9804 Magnetic Adapter Set (optional)

Usage Notes

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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1

Overview

1.1 Product Overview and Features

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.

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

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Overview

1.2 Part Names

Front Rear

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(CM4376)

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1 Operation grip

2 Jaw open/closed mark

(The jaws are open if the mark is not

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showing.)

3 SHIFT key

(Selects function indicated in blue lettering.)

4 Jaw

5 Barrier

6 Serial 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.)

7 Rotary switch

8 HOLD key

9 LCD

10 Battery cover

11 Operation keys

12 Measurement terminals

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NO

NONO

Making 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 foreign matter on the



measurement terminals. (p. 12)

The test leads are not broken.



1 Ω or less

OK

There is no damage to the test lead



insulation, and neither the white sheathing nor

metal conductor inside the wire are exposed.

The instrument is neither damaged nor cracked.



No indicators are missing.



(All lit up)

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Current Measurement

2.2 Current Measurement

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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).

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3

Clamp the instrument around a conductor.Turn the rotary switch.

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AUTO

(AUTO AC/DC)

e.g.: 3P4W (3-phase, 4-wire) circuit

breaker (AC current measurement)

Be sure that the currents
direction points the arrow.

(AC A)

(AC+DC A)(DC A)

Hz

(Frequency)

Manual Hold / Auto Hold

Current Measurement

Manual hold Auto hold

Press for 1 sec.

Measured value



retains.

Pressing the HOLD key again cancels
the measured value hold function.

(Measured value stabilizes.)

Measured value automatically retains.

Pressing the HOLD key for 1 sec. cancels the auto
hold function.

1



blinks.

2

Clamp the instrument around a
conductor.

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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.

Held measured value

Measured
value

Auto hold
e.g.: 100.0 A

Fluctuation range

Fluctuation range

Auto hold
e.g.: 99.0 A

Fluctuation range

Threshold
e.g.: 12.0 A

Start

End

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.

End

Start

Measurement

End

Start

Time

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Current Measurement

Measurement function Fluctuation range Threshold value

AUTO A
AC current
DC current
AC+DC current

AC voltage
DC voltage
(excluding the 600.0 mV range)
AC+DC voltage

Resistance
Continuity

Diode 1.800 V range: within 40 counts 1.800 V range: 1460 counts

The auto hold function only operates for the above measurement functions.

Within 120 counts 120 counts

6.000 V/60.00 V/600.0 V range:
within 120 counts
1000 V range: within 20 counts
1500 V range: within 30 counts

/6.000 kΩ/60.00 kΩ/

600.0

Ω

600.0 k

Ω range: within 100 counts

6.000 V/60.00 V/600.0 Vrange:
120 counts
1000 V range: 20 counts
1500 V range: 30 counts

600.0 Ω/6.000 kΩ/60.00 kΩ/

600.0 k

Ω range: 4900 counts

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Current Measurement

Filter Function

FILTER OFF FILTER ON

Measured value including noise

Press for 1 sec.

Measured value with reduced noise

Frequency characteristics when using the

lter function (100 A input)

FILTER OFF

FILTER ON Passband 100 [Hz]

Measured value [A]

Frequency [Hz]

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Turn off the lter function when performing

measurement of power supply frequencies in excess

of 100 Hz, for example on an aircraft or ship.

Filter OFF