General CM660 User manual

RUGGED
AUTO RANGING
TRUE RMS
AC/DC CLAMP METERS
USER’S MANUAL
CM660: 0 TO 600A, MAX
CM700: 0 TO 1000A, MAX
Please read this manual carefully and thoroughly before using this product.

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TABLE OF CONTENTS
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Key Features . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 –4
What’s in the Blister Pack . . . . . . . . . . . . . . . . . . . . 4
Product Overview . . . . . . . . . . . . . . . . . . . . . . . 4 –7
Safety Instructions . . . . . . . . . . . . . . . . . . . . . 7 – 10
Setup Instructions. . . . . . . . . . . . . . . . . . . . . . . . . 10
Install Batteries . . . . . . . . . . . . . . . . . . . . . . . . . 10
Operating Instructions. . . . . . . . . . . . . . . . . . 11 – 24
General Instructions. . . . . . . . . . . . . . . . . . 11 – 14
anging Options . . . . . . . . . . . . . . . . . . . . . . 11
Holding eadings . . . . . . . . . . . . . . . . . . . . . 11
Tracking Max and Min eadings . . . . . . 11 – 12
Making elative Measurements . . . . . . . . . . 12
Disabling Auto Power Off (APO). . . . . . . 12 – 13
Using the Analog Bar Graph. . . . . . . . . . . . . . 13
Turning on the Backlight . . . . . . . . . . . . 13 – 14
Measuring AC or DC Current . . . . . . . . . . . 14 – 16
Measuring AC Inrush Current . . . . . . . . . . . . 15
Measuring Microamp Currents . . . . . . . 15 – 16
Measuring AC or DC Voltage. . . . . . . . . . . . 16 – 19
Using the Non-contact Voltage Detector 16 – 19
Measuring esistance . . . . . . . . . . . . . . . . . . . . 20
Checking for Continuity . . . . . . . . . . . . . . . 20 – 21
Checking the Integrity of a Diode. . . . . . . . . . . . 21
Measuring Capacitance . . . . . . . . . . . . . . . . . . . 22
Measuring Frequency and Duty Cycle . . . . 22 – 23
Measuring Temperature . . . . . . . . . . . . . . . 23 – 24
Specifications . . . . . . . . . . . . . . . . . . . . . . . . 24 – 27
Operating & Maintenance Tips . . . . . . . . . . . . . . . 28
Warranty Information . . . . . . . . . . . . . . . . . . . . . . 29
eturn for epair Policy . . . . . . . . . . . . . . . . . . . . 30

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INTRODUCTION
Thank you for purchasing General Tools &
Instruments’ (General’s) CM660 or CM700 Rugged
Auto Ranging True RMS AC/DC Clamp Meter. Please
read this user’s manual carefully and thoroughly
before using the instrument.
Each meter combines the functions of a voltmeter and
a clamp-type ammeter. The meters are designed for
use in an industrial setting by HVAC/R contractors,
building maintenance technicians, MRO
(maintenance, repair and operations) personnel at
process and power plants, electricians and
electrical/electronic technicians.
The only difference between the CM660 and CM700
involves their current measurement range and
resolution. Where the CM660 has a 0 to 600A
measurement range and a maximum current resolution
of 0.01A, the CM700 has a 0 to 1000A measurement
range and a maximum resolution of 0.1A.
Both clamp meters are easy to use and ruggedly built.
Each meets the ETL CAT III 600V, CAT II 1000V safety
standard.
KEY FEATURES
• 16 functions, 49 ranges
• Measures AC/DC current, AC/DC voltage, resistance,
capacitance, frequency and duty cycle
• Also measures temperature from -58° to 1112°
(-50° to 600°C) using included “K” type stem
thermocouple
• Uses beeper to verify integrity of diodes and check
circuits for continuity
• 0 to 200애A/2000애A AC/DC ranges for measuring
flame rod current with 0.1애A/1애A resolution using
included test leads

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• Built-in Non-Contact Voltage (NCV) detector with four
sensitivity settings and audible and visual alerts
• Large backlit digital LCD with two 6000-count
readouts for simultaneous display of real-time
current or voltage on primary readout and line
frequency on secondary readout
• ast-response analog bar graph
• Bright LED work light
• Manual ranging and MIN/MAX display options
• Data HOLD and REL (zero) buttons
• INRUSH mode for measuring surge current during
motor startup
• 1.65 in. (42mm) jaw opening (largest in its class) for
conductors up to 550 MCM resists side torque
• Rugged housing can survive multiple drops onto
concrete from height of 5 ft. (1.6m)
• 20-minute Auto Power Off (APO) function can be
disabled
• ETL certified CAT III 600V, CAT II 1000V
• 3 year limited warranty
WHAT’S IN THE BLISTER ACK
The meter is supplied in a blister pack with a cavity in
the rear for a soft black nylon carrying pouch. Inside
the pouch are a set of double-insulated test leads
with screw-on alligator clips, a “K” type stem
thermocouple probe and plug adapter, 3 “AAA”
batteries and this user’s manual.
RODUCT OVERVIEW
ig. 1 shows the labels and positions of the controls,
indicators and physical structures of the CM660 and
CM700. ig. 2 shows all possible indications on the
LCD of either unit. amiliarize yourself with the
functions and meanings of these controls, indicators
and connectors before moving on to the Setup
Instructions and Operating Instructions.

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Fig. 1.
The controls,
indicators and
physical structures
of the CM660
and CM700.
1
. Non-contact voltage (NCV) sensor
2 . NCV visual indicator
3 . LED work light
4 . Rotary function switch
5 . Multi-function buttons:
ZERO/REL —Used to 1) Reset DC current
measurement baseline
to 0A, 2) Enter relative
measurement mode
, in which main readout shows
difference between real-time reading and stored
reading shown on secondary readout, 3)
Disable
meter’s Auto Power Off
function.
AUTO
1
2
3
4
7
8
6
5
9

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FU C/I RUSH —1) Selects among resistance
measurement, capacitance measurement, diode
integrity and continuity check modes with rotary
function switch in position, 2)
Switches
between AC and DC
with rotary function switch in
or position, 3)
Enters surge current
measurement mode
with rotary function in
position, 4)
Enters CV sensitivity set mode if
pressed and held when powering on the meter.
MAX/MI —Pressed once, enters Max/Min mode .
Meter displays maximum value recorded during
current measurement session on secondary
readout.
Pressed twice, switches to display
minimum
value recorded during current
measurement session on secondary readout.
Pressed a third time, exits Max/Min mode.
HOLD—Pressed once , holds measured value(s)
(freezes main and secondary readouts).
Pressed
again
, releases both readouts.
—
Pressed briefly , enters manual ranging
mode in broadest range. Each subsequent button
press switches to next-narrowest full-scale
measurement range. Pressing button in narrowest
range returns to auto ranging mode.
Pressed and
held
for >2 seconds, activates display backlight
(and LED work light if rotary function switch is in
or position).
6 . Test lead jacks
7 . Clamp jaw release
8 . Clamp jaw
9 . Battery compartment (on back)

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Fig. 2. All possible display indications
SAFETY INSTRUCTIONS
 Warning 
To avoid possible electric shock or personal injury,
and to avoid damaging the meter or the equipment
under test:
• Do not use the meter in any way not detailed in this
manual or the meter's safety features may be
compromised.
• Before using the meter, inspect the case.
Do not use the meter if it is damaged. Look for
cracks or missing plastic. Pay particular attention to
the insulation around the connectors.
• 
WAR I G Inspect the test leads for damaged
insulation or exposed metal. Check the test leads
for continuity. Replace damaged test leads before
using the meter.
• Verify the meter’s operation by measuring a known
voltage. Do not use the meter if it operates
abnormally. Protection may be impaired. When in
doubt, have the meter serviced.
• 
WAR I G Do not apply more than the rated
voltage, as marked on the meter, between the
terminals or between any terminal and ground.
AUTO

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•  WAR I G Do not measure voltages above 1000V
in Category III installations.
• 
WAR I G Do not measure voltage when the
function switch points to the resistance (ohms),
current, capacitance or temperature settings. Never
measure current when the switch points to the
resistance (ohms), capacitance or temperature
settings.
• Use caution when working with voltages above
42VACRMS, or 60VDC. These voltages pose a shock
hazard.
• Use the proper terminals, function, and range for all
measurements.
• 
WAR I G Do not operate the meter around
explosive gas, vapor, or dust.
• 
WAR I G When using the probes, keep your
fingers behind the finger guards. Do not touch the
metal probes of the test leads when making a
measurement.
• When making connections, connect the black (–)
test lead before connecting the red (+) test lead;
when disconnecting, disconnect the red (+) test
lead before disconnecting the black (–) test lead.
• Disconnect circuit power and discharge all high-
voltage capacitors before measuring/testing
resistance, continuity, diodes, or capacitance.
• or all DC functions in both auto and manual
ranging mode, to avoid the risk of shock due to
possible improper reading verify the presence of
any AC voltages by first using the AC function. Then
select a DC voltage range equal to or greater than
the AC range.
• Before measuring current, turn off power to the
circuit before connecting the meter.
• Do not operate the meter with the case (or part of
the case) removed.

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• Use only three “AAA” batteries, properly installed in
the battery compartment, to power the meter. Do
not use rechargeable batteries.
• Replace the batteries as soon as the low battery
indicator “ ” appears. Operated with weak
batteries, the meter might produce false readings
that could lead to electric shock and personal injury.
• Remove the test leads from the meter before
opening the meter case or battery compartment.
Electr cal Symbols Used On the
Meter and In Th s Manual
Symbol Description Symbol Description
AC (Alternating use
Current)
DC Double
(Direct Current) Insulated
Caution, risk of Risk of danger.
electric shock. Important
Hazardous information.
voltage. Refer to the
manual.
Battery
(Low battery) Earth ground
when shown
on display
Diode Continuity
Beeper
AC or DC AC/DC

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Symbol Description Symbol Description
Application and or measurements
removal from made on building
hazardous live equipment such
conductors as distribution panels,
permitted feeders and short
branch circuits, and on
lighting systems in
large buildings.
SETU INSTRUCTIONS
INSTALL BATTERIES
The battery compartment of the CM660/700 is
located at the back of the meter.
To open the compartment, use a small Phillips-head
screwdriver to remove the single screw securing the
battery compartment cover. Be careful not to lose the
small screw. Put the screw and the cover to the side.
Install the three supplied “AAA” batteries in the
battery compartment. Use the polarity marks
stenciled inside the compartment as a guide.
Replace the battery compartment cover and secure it
with the Phillips-head screw.
or measurements on
circuits connected
directly to the source of
power for a given build-
ing (for example, on the
cable to the power
transformer ahead of
a building’s circuit
breakers). Very high
levels of energy avail-
able at CAT IV level
make arc flash possible.
Auto Power Off
function CAT IV