
Introduction
Thank you for purchasing the HIOKI “3127-10,3128-10 CLAMP ON
HiTESTER”. To obtain maximum performance from the product,
please read this manual first, and keep it handy for future reference.
3127-10,3128-10
CLAMP ON HiTESTER
INSTRUCTION MANUAL
January 2008 Revised edition 1 Printed in Japan
3127A981-01 08-01H
3127-10
1
3128-10
2
3
4
6
5
7
8
9
10
1
2
3
4
6
5
7
8
9
1
Jaws 2 Meter lock switch
3 Range selector switch 4 Ohms(Ω) terminal
5 Zero adjust screw 6 Voltage terminal
7 Pointer 8 Meter scale 9 0 ΩADJ knob
10Carring strap
HEAD OFFICE
81 Koizumi, Ueda, Nagano 386-1192, Japan
TEL +81-268-28-0562 / FAX +81-268-28-0568
E-mail: os-com@hioki.co.jp URL http://www.hioki.com/
HIOKI USA CORPORATION
6 Corporate Drive, Cranbury, NJ 08512, USA
TEL +1-609-409-9109 / FAX +1-609-409-9108
Inspection
When you receive the product, 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.
Preliminary Checks
Before using the product the first time, verify that it operates normally
to ensure that the no damage occurred during storage or transport. If
you find any damage, contact your dealer or Hioki representative.
Safety Information
• Mishandling this product during use could result in
injury or death, as well as damage to the product. 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 product defects.
• To avoid short circuits and potentially life-threatening
hazards, never attach the clamp to a circuit that operates at more than 750Vrms AC, or over bare conductors.
• In some cases, pow er lin es may carry volt age sp ikes of
several times the normal supply voltage. When measuring such power lines, there is a danger of electric
accidents that may result in injury or death. For safety
reasons, this tester should not be used to measure
power lines carrying more than 250 V . When measuring
such power lines, always use a tester with built-in
overcurrent protection to guard against short circuits,
such as models 3008 and a device showing the CAT III
marking.
An industrial power line refers to a high-capacity supply circuit to
equipment in factories or offices. A high-capacity supply circuit refers
generally to a line carrying 20 A or more. This does not therefore
include supply lines protected by overcurrent (fuse) or distribution
breakers.
This manual contains information and warnings essential for safe
operation of the instrument and for maintaining it in safe operating
condition. Before usin g it, be sure to carefully read the foll owi ng s afe ty
precautions.
Safety Symbol
In the manual, the symbol indicates particularly important information that the user should read before using the
product.
The following symbols in this manual indicate the relative importance
of cautions and warnings.
Indicates th at i ncorr ect oper ati on pre sen ts an ex trem e haz ard that could result in serious injury or death to the user.
Indicates that in co rrec t operation present s a si gni fic an t hazard thatcould 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.
Specifications
Accuracy guaranteed for one year at 23±5°C(73±9°F), 80%RH or less
3127-10 3128-10
6,15,60,150,300 A
AC A
AC V 150,300,750 V f.s. re ading±3%
DC V 75 V f.s. reading±3%
Ω
Temperature scale
Protective system
Core conductor
diameter
Dimensions
Mass
The maximum per-
missible circuit
voltage
Drop proof from one meter above concrete floor
Operating tempera-
ture and humidity
Storage tempera-
ture and humidity
Power source
Fuse
Accessories
Options
The maximum permissible circ uit voltage 750 V r ms AC
-50°C to 200°C(standard, with optional probe)
-50°F to 300°F(for USA only, with optional probe)
Protection in
Approx.78W×190H×34Dmm
Approx.3.07”W×7.48”H
Approx.340 g
Approx.12.0 oz.
-10 to 50°C(14 to 12 2°F) 70%RHor less
F0.5 A/250 V 30×6.4 dia. mm(non arcing type)
9351(Carrying case) - - - 1 9148(Carrying case) - - - -1
(Insulated conducto r )
f.s. reading± 3%
0 to 1 kΩ Central scale 30 Ω,R100
33 mm
1.30”
×1.34”D
0 to 40°C(32 to 104°F) 70 %R H or les s
Scale lengt h±3%
Scale lengt h±3%
Ω
range up to 250 V AC commercial power
Rated power voltage 1.5 VDC×1
R6P manganese battery×1
Internal resistance 1.8
9207-30 (Test lead) - - - - - - - - -1
R6P manganese battery- - - - - -1
Spare fuse(F0.5 A/250 V)- - - - -1
Strap band - - - - - - - - - - - - - - -1
Instruction manual - - - - - - - - - -1
CT-101A LINE SPLITTER
9021-01TEMPERATURE PROBE
15,60,150,600,1500 A
1000 A or more max.
2minutes
input
55 mm, width 80mm
2.17”,width 3.15”
Approx.99W×273H×34Dmm
Approx.3.90”W×10.75”H
×1.34”D
Approx.570 g
Approx.20. 1 oz .
AC750 V
Ω
Operating Precautions
Follow these precautions to ensure safe operation and to obtain the
full benefits of the various functions.
• This product should only be connect ed 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, short circuits and damage to the
instrument, observe the following precautions:
Check the position of the range switch before taking measurements.
Disconnect the test leads from the measurement object
before switching ranges.
• Do not allow the instrument to get wet, and do not take measurements with wet hands. This may cause an electric shock.
• To avoid electric shock when measuring live lines, wear
appropriate protective gear, such as insulated rubber gloves,
boots and a safety helmet.
• To avoid electrical shock accidents while measuring voltage,
make sure that the metal parts of the clamp-on sensor do not
contact the skin or other metallic objects.
• To avoid electrical accidents while measuring current, do not
connect the test leads to the instrument.
• 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 instrument in such conditions
could caus e an ele ct ric sh oc k, so co ntact yo ur deale r or Hioki
representative for replacements (Model 9067).
• Note that the instrument may be damaged if voltage or current the
measurement range.
• Do not store or use th e inst rument where it co uld be expos ed to direct sunlight, high tem perature or humi dity, or condens ation. Under
such conditions, the instrument may be damaged and insulation
may deteriorate so that it no longer meets specifications.
• Correct measurement may be impossible in the presence of strong
magnetic fields, such as near transformers and high-current conductors, or in the presence of strong electromagnetic fields such as
near radio transmitters.
• To avoid corrosion from battery leakage, remove the batteries from
the instrument if it is to be stored for a long time.
• If the tester shows incorrect operation during use, discontinue use at
once and contact your dealer or hioki representative.
Parts Names

Measurement Procedure
2
3
3
3127-10 3128-10
3127-10
3128-10
Replacing the Battery
Maintenance
Measurement Preparations
1. Unlock the meter (switch the lock knob to the open position, the
right).
2. Check that the needle is aligned with 0, and adjust it with the zero
adjust if it is not.
3.Always check the fuses a nd zero adjust the meter before use.
Set the meter to the Ω range, short out the lead pins, and verify
that the meter wobbles. In the event of a meter problem, check the
fuse first.
AC current Measurement (AC A)
• To avoid electrical accidents while measuring current, do not
connect the test leads to the instrument.
• Current measurements exceeding 1000 A should be of short
duration. Heat builds up in the cla mp c ore prop ortion ate to the
current value, and will reach a dangerous level over a long
period of time.(3128-10)
Attach the clamp around only one conductor. Single-phase (2-wire) or
three-phase (3-wire) cables clamped together will not produce any
reading.
1.Switch the range selector 3 to the highest range of AC V or DC V.
2.Insert the test lead into the V terminal 6.
3.Contact the tip of the tes t le ad in parallel with the me asurem en t unit.
4. If the reading is low, lower the range one step at a time and check
the reading.
Resistance Measurement (Ω)
Turn off the power and discharge the capacitors before measuring
resistance in a circuit.
• Be sure to insert them with the correct polarity. Otherwise,
poor performance or damage from battery leakage could
result.
• To avoid the possibility of explosion, do not short circuit, disassemble or incinerate batteries.
• Handle and dispose of batte ries in a cco rdanc e w ith loca l regu lations.
1.Remove the back casing screw and take off the back casing.
2.Replace the battery with new one.
3.After replacing the battery, always replace the back casing and
tighten the screw before using the unit.
Replacing the 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.
Fuse type: F0.5 A/250 V (non-arcing) 6.4Å~30 mm dia.
1. Remove the back casing screw and take off the back casing.
2.Replace the fuse with new one.
To clean the instrument, wipe it gently with a soft cloth moistened with
water or mild de terg ent. Never use solv en t s s uc h as b enz en e, alcohol,
acetone, ether, ketones, thinners or gasoline, as they can deform and
discolor the case.
Service
• If the instrument s eems to be ma lfunct ioning , conf irm tha t the b atteries are not discharged, an d that the test l eads an d fuse ar e not open
circuited before contacting your dealer or Hioki representative.
•Pack the
ping, and include a description of existing damage. We cannot
accept responsibility for damage incurred during shipping.
instrument so that it will not sustain damage during ship-
1.Set the range selector 3 to the highest current range.
2.Clamp one conductor inside the core.
3. If the reading is low, lower the range one step at a time and check
the reading.
4. If measurement is performed where the meter is difficult to read,
slide the meter lock to the left.
Voltage Measurement (AC V / DC V)
• The maximum input voltage is 750V AC,75V DC. Attempting
to measure voltage in excess of the maximum input could
destroy the instrument and result in personal injury or death.
• To avoid electric shock, short circuits and damage to the
instrument, observe the following precautions:
Check the position of the range switch before taking measurements.
Disconnect the test leads from the measurement object
before switching ranges.
To avoid possible electrical shock or damage to the clamp sensor, avoid touching the exposed metallic parts of the clamp sensor with your hands or any other metallic objects while
measuring voltage.
1.Set the range selector 3 to Ω
2.Connect the test lead to the Ω terminal 4.
3.Short out the tips of the tes t leads and adjust th e 0
that the needle reads zero. If it will not adj ust to 0, the battery s hould
be replaced.
4. Contact the test leads to the test location and read the resistance
directly.
Ω ADJ knob 9 so
Temperature Measurement
When the optional 9021-01 temperature probe is used, the TEMP
scale can be used for d irect readin g of temperature . The range used is
“×100 “.
Replacing the Bat tery 11 and Fuse 12
• To avoid electric shock when replacing the batteries and fuse,
first disconnect the test leads from the object to be measured.
• After replacing the batteries or fuse, replace the cover and
screws before using the instrument.
• Use the fuse is the one stored inside the main unit.
• Be sure to replace the spare fuse with a new one if it is used to
replace a blown fuse.
• For removal refer to figure 1, and for insertion to figure 2.
3.After replacing the fuse, always replace the back casing and tighten
the screw before using the unit.
Measurement of current and voltage in
equipment with double-core cords
When current and voltage are measured in equipment with doublecore cords, the optional CT-101A line splitter makes measurement
easy.
The maximum input voltage and current of the CT-101A is 100
VAC, 15 Arms.
Ensure that the input does not exceed the maximum input voltage or current to avoid instrument damage, short-circuiting and
electric shock resulting from heat building.
measurement method
1.Plug the power cord of the electrical equipment to be measured into
the line splitter, and the line splitter plug into the power outlet.
2. Current can be measured by running the clamp tester core through
the line splitter window. ×1 and ×10 readings are provided.
3. Voltage can be measured by inserting the test pin into the voltage
measurement terminal 13.