Overview Inspection Maintenance and Service Safety CLAMP ON

Safety Symbol
Instruction Manual
January 2012 Revised edition 2
Printed in Japan
3291C981-02 12-01H
In the manual, the
symbol indicates particularly important
information that the user should read before using the instrument.
symbol printed on the instrument indicates that the user
should refer to a corresponding topic in the manual (marked with
symbol) before using the relevant function.
Names and Functions of Parts
Indicates AC (Alternating Current).
Clamp Sensor
Indicates DC (Direct Current).
Indicates that the instrument may be connected to or disconnected from a live circuit.
Indicates a double-insulated device.
Press both
MAX value
• Clear
Indicates a prohibited action.
Symbols for Various Standards
This symbol indicates that the instrument conforms to safety 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).
Press once
• Data hold
Press 2 sec.
• Back light
Notation of the This Manual
Press once
• Maximum data
• Instantaneous
Press 2 sec.
• Power OFF
Press once
• Digital display
Press 2 sec.
• Filter OFF/ON
Display (LCD)
The following symbols in this manual indicate the relative importance
of cautions and warnings.
Thank you for purchasing the HIOKI Model 3291-50 CLAMP ON
HiTESTER. To obtain maximum performance from the instrument,
please read this manual first, and keep it handy for future reference.
Because it employs a small, thin-type sensor the 3291-50 Clamp On
HiTester can clamp even in narrow places. In addition, the angle of
the display panel can be changed to suit the measuring location and
the back light makes the instrument easy to use even in dark places.
Initial Inspection
When you receive the instrument, inspect it carefully to ensure
that no damage occurred during shipping. If damage is evident,
or if it fails to operate according to the specifications, contact
your dealer or Hioki representative.
Maintenance and Service
• To clean the instrument, wipe it gently with a soft cloth moistened with water or mild detergent. Never use solvents such
as benzene, alcohol, acetone, ether, ketones, thinners or
gasoline, as they can deform and discolor the case.
• If the protective functions of the instrument are damaged, either
remove it from service or mark it clearly so that others do not
use it inadvertently.
• If the instrument seems to be malfunctioning, contact your
dealer or Hioki representative.
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.
This instrument is designed to comply with IEC 61010
Safety Standards, and has been thoroughly tested for
safety prior to shipment. However, mishandling during
use could result in injury or death, as well as damage to
the instrument. However, 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.
Indicates that incorrect operation presents a significant hazard
that could result in serious injury or death to the user.
(Magnified View)
Alternating current (AC)
MAX MAX value
Data hold function
Bar graph
Indicates that incorrect operation presents a possibility of
injury to the user or damage to the device.
Indicates advisory items related to performance or correct
operation of the instrument.
Measurement categories
Over range
* The device considers the maximum
displayed value to be the MAX value.
• Do not store or use the instrument where it could be exposed
to direct sunlight, high temperature or humidity, or condensation. Under such conditions, the instrument may be damaged and insulation may deteriorate so that it no longer
meets specifications.
• This instrument contains a magnetic core. The device
should not be used by anyone with a pacemaker or any other
electronic medical devices installed in his body.
Display update rate
1.1 sec. or less
LCD: monochrome, 91 segments
Operating temperature 0 to 40°C (32 to 104°F), 80%RH or less
and humidity
(with no condensation)
Storage temperature -10 to 50°C (14.0 to 122.0°F), 80%RH or less and humidity
(with no condensation)
indoors, Pollution degree 2,
Location for use
Altitude up to 2000 m (6562 feet)
Maximum rated
25 mVA
Power supply
CR2032 x 1 Lithium battery
Battery lifetime
Approx. 115 g (4.1 oz.)
Dielectric strength
5312 Vrms /15sec., 5 mA sensitivity current
between the chassis and clamp core
Applicable standards Safety EN61010
EMC EN61326
2.00 A to 60.00 A
0.01 A
600 A 54.0 A to 600.0 A
0.1 A
540 A to1000 A
ON: Grasping the lever and opening wide the Clamp
Sensor (sideways).
OFF: Press POWER OFF key for 2 seconds or longer.
Details of operation: Low pass filter ON/OFF
Cutoff frequency:180 Hz±30 Hz (-3dB)
Initial setting: OFF (Always OFF when the power supply
is turned on; non-filtered data is not saved)
Activate/De-activate: Press FILTER key for 2 seconds or
*When set to ON, the filter removes noise and other
unwanted frequency components.
Data hold
Details of operation: Holds measured values
(data update is halted)
Activate: Pressing the
key once.
De-activate:Pressing the
key once. Filter ON/OFF
MAX value display
Details of operation: Displays the maximum measured
values reached since the power has been turned on.
Activate/De-activate: Pressing the MAX key once.
Clear displayed maximum value: Press MAX key and
HOLD key at the same time. Filter ON/OFF
Auto power-off
Details of operation: The power cuts off when "0" is
displayed continuously for 1 minute.
Any key operation is not performed for approx.10
To de-activate: Power ON while pressing the
Battery Level
Details of operation:Displays 4 levels of remaining
battery charge.
*Refer to “Replacing Battery”.
Back light
Activate/De-activate: Press
key for 2 seconds or
longer. (About 15 seconds lighting.)
Frequent use of backlight reduces battery life.
Liquid crystal display
(LCD) reversal
Details of operation: Automatically reverses when the
display panel is opened and closed.
Manual reversal: Pressing the
key once.
*Refer to “Opening and Closinng the Display Panel”.
Bar graph
Shows the proportion of the measured value to the
Over-Range Display
Displays “OVER”when a high crest factor current is
inputted, which means an out of the accuracy
*Refer to “Crest factor”.
(45 Hz to 66 Hz)
(66 Hz to 400 Hz)
±1.5% rdg. ±5dgt.
(50 Hz to 60 Hz)
Effect of conductor
Within±5.0% (in any position based on the center of
the clamp sensor)
Maximum rated
voltage to earth
600 Vrms Measurement category III (anticipated
transient overvoltage 6000 V), 300 Vrms Measurement
category IV (anticipated transient overvoltage 6000 V)
Crest factor
2.8 or less (up to 600 A), 1.68 or less (1000 A range)
Diameter of
30 mm dia. or less
measurable conductor
Response time
Within 0.05 × precision specification / °C
Other than 23°C±5°C (73°F±9°F)
1.1 sec. or less
9757 Carrying case, Strap, Instruction manual,
CR2032 Lithium battery
Power supply control
Less than 0.30 A zero-suppression
Approx.20 hours
(continuous, no load, at 23°C)
Approx. 50 W × 136 H × 26 D mm
• Temperature and humidity for guaranteed accuracy: 23±5°C
(73±9°F), 80%RH or less.
• Guaranteed accuracy period: 1 year, opening and closing of
the Clamp Sensor 10,000 times, whichever comes first.
• Guaranteed accuracy range: 2.00 A or above
AC current A rms (true rms indication, Auto range)
1000 A
Do not allow the instrument to get wet, and do not take
measurements with wet hands. This may cause an electric shock.
General Specifications
Measurement specification
60 A
Follow these precautions to ensure safe operation and to obtain
the full benefits of the various functions.
Battery low warning (4 levels)
Usage Notes
Accuracy spec.
:±1.5%rdg. ±5dgt. (A) Reading error (± %rdg.): ± 1.5% of 30.00 A =
± 0.45 A
Measurement range :60.00 A
(B) Digit error (± dgt.):± 5dgt. =± 0.05 A (Due to
Measurement values :30.00 A
minimum resolution of 0.01 A)
(C) Total error: (A)+(B) = ± 0.50 A
The limit error value for the measured value of
30.00 A is 29.50 A ~ 30.50 A based on the total
error (C).
Rated supply voltage 3 VDC
Indicates that incorrect operation presents an extreme hazard
that could result in serious injury or death to the user.
This instrument complies with CAT III 600 V, CAT IV 300 V safety
requirements. To ensure safe operation of measurement instruments, IEC
61010 establishes safety standards for various electrical environments,
categorized as CAT II to CAT IV, and called 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: Primary electrical circuits of 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 protection device (distribution panel).
Using a measurement instrument in an environment designated with a highernumbered 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.
We define measurement tolerances in terms of rdg. (reading) and dgt. (digit) values, with the following meanings:
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.
Maximum input current 1000 A
Measurement Procedures
Pre-Operation Inspection (Check the following before using the instrument.)
• Before using the instrument the first time, verify that it operates normally to ensure that the no damage occurred during
storage or shipping. If you find any damage, contact your
dealer or Hioki representative.
• The clamp sensor or the case shall be free of damage. (If
damage has occurred, avoid using the instrument. Use of the
instrument under these conditions may result in electric
• The mating portions of the clamp sensor should be free of
any scratches or cracks.
• Battery power should be near full capacity when power is
turned on. (Refer to “Replacing Battery”)
• The reading should be around 0 A when no measurements
are being made.
Open Jaws to Power On.
1. Clamp the tester on the conductor, so that the conductor
passes through the center of the clamp core.
Replacing Battery
Opening and Closing the
Display Panel
• To avoid electric shock when replacing the battery first
disconnect the clamp from the object to be measured.
After replacing the batteries, replace the cover and
screws before using the instrument.
• Use only CR2032 lithium battery. Use of any other battery may result in explosion.
• Be sure to insert them with the correct polarity. Otherwise, poor performance or damage from battery leakage
could result.
• Battery may explode if mistreated. Do not short-circuit,
recharge, disassemble or dispose of in fire.
• Handle and dispose of batteries in accordance with local
• Keep batteries away from children to prevent accidental
• To avoid corrosion from battery leakage, remove the batteries from the instrument if it is to be stored for a long
Adjust the angle of the display panel for better viewing.
• Clamp the tester on one wire only.
• Put the conductor perpendicular to the sensor, as shown in the sketch.
2. The effective value is shown on the digital display.
Display example
Crest factor
• This instrument should only be connected to the secondary side of a breaker, so the breaker can prevent
an accident if a short circuit occurs. Connections
should never be made to the primary side of a breaker,
because unrestricted current flow could cause a serious accident if a short circuit occurs.
• To avoid electric shock, do not touch the portion
beyond the protective barrier during use.
“Crest factor = Waveform peak value/ Internal rated range” is defined for this
instrument. There are cases when the accurate measurement cannot be performed with our previous models, because a top portion of the waveform is
clipped off due to the rated range if a high crest factor current (= RMS is low and
a waveform peak is high) is flowed. This instrument defines the range based on
a waveform peak value and measured value so that the accurate measurement
can be performed. As for a high crest factor current, its measured value becomes small to the range. If a current exceeding a crest factor of 2.8 is inputted,
“OVER”is displayed. This measurement is the out of accuracy guarantee
range and the measured value is for reference purpose only.
• Be careful to avoid dropping the instrument or otherwise
subjecting them to mechanical shock, the Clamp Sensor tip
will be damaged, negatively influencing measurement.
• Do not input current greater than 1000 A. It will damage the
at the upper left on the display screen indicates the
remaining power level. When the battery approaches the
exhausting value,
is displayed and a few minutes later,
power turns off automatically. When
is displayed, the
accuracy of measurement value is not guaranteed. Replace
the new batteries soon.
• At a low or high temperature, the battery life is reduced faster.
• The batteries included with the device were installed for factory testing purposes. CR2032 lithium batteries can be purchased at electronics and appliance stores where specialized
batteries are sold.
Attaching the strap
Make the strap go through the
hole just like the Figure shown.
Error Display
When an error is displayed on the LCD, the HiTester requires
repair. Contact your supplier or Hioki representative.
Error Display
Position the battery
so that the plus (+)
side is on top.
Battery cover
Regarding the MAX value display
(1) Press the MAX key once to confirm the MAX value. Whenever a maximum
value is updated, the display will be updated.
(2) A maximum value will be cleared by pressing【MAX】key and【HOLD】key
simultaneously whether when a maximum value is displayed or an instantaneous value is displayed.
• As far as the Data Hold mode is on, MAX value cannot be updated.
• The MAX value is cleared with FILTER ON/OFF.
Filter function
• Correct measurement may be impossible for the case of rush
current or significantly fluctuating current.
• There are cases when error could be larger depending on
positioning of sensors and conductor.
• When the measuring value exceeds 1000 A the digital display
will blink.
• Waveforms around 20 Hz or below may be displayed as “----”.
• At a low temperature, there are cases when the reading may
not be around 0 A without any input signal. But it does not
affect measurement.
Previous models
To avoid short circuits and potentially life-threatening hazards, never attach the instrument in current
measurement mode to a circuit that operates at
more than the maximum rated voltage CAT III 600 V,
CAT IV 300 V, or over bare conductors.
Display Panel
AC Current Measurement
The display can also be
reversed by pressing
Fix the strap for fall prevention.
Replacing the Batteries
• Please note that waveforms that include elements outside the
frequency characteristic range may not be measured correctly.
• Correct measurement may be impossible in the presence of
strong magnetic fields, such as near transformers and highcurrent conductors, or in the presence of strong electromagnetic fields such as near radio transmitters.
Take measurements with the display
panel flipped open in order to view the
measurement results more clearly, especially in tight locations, without needing
to twist the jaw at an awkward angle.
The default setting of Filter is OFF. Please change the setting
according to the use.
1. Press and hold the POWER OFF key for 2 seconds or
longer to turn off the device's power.
2. Remove the battery cover screws on the back of the device
with a Phillips screwdriver, then remove the battery cover.
3. Replace with a new battery. When inserting a new battery
(CR2032 lithium battery), be sure to position the polarities
in their proper orientations.
4. Replace the battery cover and fasten the screws.
This instrument contains a CR Coin Lithium Battery which
contains Perchlorate Material - special handling may apply.
See www.dtsc.ca.gov/hazardouswaste/perchlorate
Internal ROM Error
Calibration Data Faulty
Remedial Action
Repair is necessary.
Contact your supplier or Hioki
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