Greenlee CM-750 User manual

999 3789.1 © 2002 Greenlee Textron IM 1464 REV 1 3/02
CM-700 • CM-750
DIGITAL CLAMP-ON
METERS
MEDIDORES DIGITALES
CON PINZA
MULTIMETRES
NUMERIQUES A
PINCES
INSTRUCTION MANUAL
INSTRUCTION MANUAL
MANUAL DE INSTRUCCIONES
MANUEL D’INSTRUCTIONS
Read and understand all of the instructions and safety
information in this manual before operating or servicing this tool.
Lea y entienda todas las instrucciones y la información sobre
seguridad que aparecen en este manual, antes de manejar estas
herramientas o darles mantenimiento.
Lire attentivement et bien comprendre toutes les instructions et
les informations sur la sécurité de ce manuel avant d‘utiliser ou de
procéder à l‘entretien de cet outil.

2
Description
The Greenlee CM-700 and CM-750 Digital Clamp-on Meters are hand-held testing devices with
the following measurement capabilities: AC and DC voltage, AC and DC current, and
resistance. They also verify continuity. The display holds a measurement for later viewing or
holds the maximum reading. The CM-750 is a true RMS reading meter.
The jaw can accommodate a conductor up to 35 mm (1.38") in diameter. In addition, the
meters feature the following:
•Autoranging
•Zeroing key for DC amps
•Selectable auto power off
•Circuit protection to 600 volts
•100 mA resolution up to 400 amps
Safety
Safety is essential in the use and maintenance of Greenlee tools and equipment. This
instruction manual and any markings on the tool provide information for avoiding hazards and
unsafe practices related to the use of this tool. Observe all of the safety information provided.
Purpose
This instruction manual is intended to familiarize all personnel with the safe operation and
maintenance procedures for Greenlee CM-700 and CM-750 Digital Clamp-on Meters.
Keep this manual available to all personnel.
Replacement manuals are available upon request at no charge.
Greenlee and are registered trademarks of Greenlee Textron.
KEEP THIS MANUAL

CM-700 • CM-750
3
Important Safety Information
Read and understand this material before operating or servicing
this equipment. Failure to understand how to safely operate this
tool can result in an accident causing serious injury or death.
This symbol is used to call your attention to hazards or unsafe practices which could
result in an injury or property damage. The signal word, defined below, indicates the
severity of the hazard. The message after the signal word provides information for
preventing or avoiding the hazard.
SAFETY ALERT SYMBOL
Immediate hazards which, if not avoided, WILL result in severe injury or death.
Hazards which, if not avoided, COULD result in severe injury or death.
Hazards or unsafe practices which, if not avoided, MAY result in injury or property
damage.

4
Important Safety Information
Electric shock and fire hazard:
•Do not expose this unit to rain or moisture.
•Do not use the unit if it is wet or damaged.
•Use test leads or accessories that are appropriate for the application. See the
category and voltage rating of the test lead or accessory.
•Inspect the test leads or accessory before use. They must be clean and dry, and the
insulation must be in good condition.
•Use this unit for the manufacturer’s intended purpose only, as described in this
manual. Any other use can impair the protection provided by the unit.
Failure to observe these warnings can result in severe injury or death.
Electric shock hazard:
•Do not apply more than the rated voltage between any two input terminals, or
between any input terminal and earth ground.
•Do not contact the test lead tips or any uninsulated portion of the accessory.
Failure to observe these warnings can result in severe injury or death.
Electric shock hazard:
Contact with live circuits can result in severe injury or death.

CM-700 • CM-750
5
Important Safety Information
•Do not operate with the case open.
•Before opening the case, remove the test leads (or jaw) from the circuit and shut off
the unit.
Failure to observe these warnings can result in severe injury or death.
•Do not attempt to repair this unit. It contains no user-serviceable parts.
•Do not expose the unit to extremes in temperature or high humidity.
See Specifications.
Failure to observe these precautions can result in injury and can damage the unit.
Do not change the measurement function while the test leads are connected to a
component or circuit.
Failure to observe this precaution can result in injury and can damage the unit.
•Unless measuring voltage or current, shut off and lock out power. Make sure that
all capacitors are discharged. Voltage must not be present.
•Using this unit near equipment that generates electromagnetic interference can
result in unstable or inaccurate readings.

6
Identification
1. Jaw
2. Lever
3. Common (COM) input terminal
4. Volts or resistance (V-Ω) input terminal
5. Display
6. Selector
7. Zero amp DC button and beeper on/off
8. Hold/maximum button
Display Icons
9. Low battery
10. –Polarity indicator
11. Direct current
12. Alternating current
13. Autoranging
14. Hold is enabled
15. Maximum value is displayed
16. Root mean square (CM-750 only)
17. Continuity indicator
18. M Mega (106)
19. k Kilo (103)
20. ΩOhms
21. m Milli (10-3)
22. V Volts
23. A Amps
24. 30.00 Numeric display
Symbols on the Unit
Warning —Read the instruction manual
Double insulation
1
28
7
6
5
3 4
12
11
10
921–23
18–20
17
13 14 15 16
24

CM-700 •CM-750
7
Using the Features
•HOLD/MAX
Press momentarily to hold the present value on the display. Press again to return to normal
mode.
To use the Maximum Hold function, press and hold before turning the unit on. Press again
to reset the stored maximum value. Press and hold for 2 seconds to return to normal
display. To remove the Maximum Hold function, turn the unit off and then back on.
•ZERO A /Ω/
For DC current measurements, close the jaw around the conductor. Orient the jaw for a
positive reading for greatest accuracy. Remove the jaw from the conductor and close it.
Press the ZERO A button. This compensates for residual magnetism in the jaw. Place the
jaw over the conductor, keeping the same orientation, and take the reading.
For continuity measurements, press to enable tone. The icon appears on the display,
and the meter switches to the 400 Ωrange. Press again to measure resistance.
•Auto Power Off Disable
Turn the selector to the OFF position. Press and hold the ZERO A /Ω/button while
quickly turning the selector to the Ω/position. The unit will now stay on until the
selector is set to OFF or until the battery is depleted (approximately 150 hours for a fresh
alkaline battery).
The next time the unit is turned on, the 30-minute Auto Power Off will be enabled.

8
Waveform
RMS Value 100 100 100 100
Average Value 90 100 87 64
Crest Factor* 1.414 1 1.73 2
(ξ)
AC Measurement
AC measurements are usually displayed as RMS (root mean square) values. The RMS value is
equal to the value of a DC waveform, which would deliver the same power if it replaced the
time-varying waveform. Two AC measurement methods are average-responding RMS
calibrated and true RMS-reading.
The average-responding RMS calibrated method takes the average value of the input signal
after full wave rectification, multiplies it by 1.11, and displays the result. This method is
accurate if the input signal is a pure sine wave. The Greenlee CM-700 is an average-
responding meter.
The true RMS-reading method uses internal circuitry to read the true RMS value. This method
is accurate, within the specified crest factor limitations, whether the input signal is a pure sine
wave, square wave, triangle wave, half wave, or signal with harmonics. The ability to read true
RMS provides much more measurement versatility. The Greenlee CM-750 is a true RMS meter.
The Waveforms and Crest Factors table shows some typical AC signals and their RMS values.
Waveforms and Crest Factors
*The crest factor is the ratio of the peak value to the RMS value; it is represented by the
Greek letter ξ.

CM-700 • CM-750
9
1. Set the selector according to the Settings Table.
2. See Typical Measurements for specific measurement instructions.
3. Test the unit on a known functioning circuit or component.
• If the unit does not function as expected on a known functioning circuit, replace the
battery.
• If the unit still does not function as expected, send the unit to Greenlee for repair. See
the address shown under Warranty.
4. Take the reading from the circuit or component to be tested.
5. If it is a DC reading, remove the clamp from the circuit and press the ZERO A /Ω/
button. Clamp the jaw around the circuit again to measure the actual DC current.
Settings Table
*Tone sounds if the measured resistance is less than approximately 50 Ω, and turns off
when greater than approximately 300 Ω.
Electric shock hazard:
Contact with live circuits can result in severe injury or death.
Operation
To measure set the selector connect the and connect the
this value … to this symbol … red lead to … black lead to …
Ω/
Continuity* and press V-ΩCOM
ZERO A /Ω/
Resistance Ω/V-ΩCOM
DC Voltage VV-ΩCOM
AC Voltage VV-ΩCOM
DC Current (600 A max.) ARemove lead Remove lead
AC Current (600 A max.) ARemove lead Remove lead

10
Typical Measurements
Current Measurement—
Clamp Around Wire
Notes:
•Clamp the jaw around one conductor
only.
•Close the jaw completely to ensure
accurate measurement.
•Center the wire in the jaw for highest
accuracy.
Voltage
Measurement
Note: For DC measurements, current
flowing through the jaw in the direction
indicated by the arrow produces a
positive reading. Position the jaw for a
positive reading for highest accuracy.

CM-700 • CM-750
11
Typical Measurements
Current Measurement—
Clamp Around Line Splitter
Notes:
•The Greenlee 93-30 Line Splitter is divided.
One section renders amps; the other
renders amps multiplied by 10.
•Close the jaw completely to ensure
accurate measurement.
•Center the line splitter in the jaw for highest
accuracy.
Resistance Measurement

12
Accuracy
See the Specifications section for operating conditions and temperature coefficient.
Accuracy is specified as follows: ±(a percentage of the reading + a fixed amount) at
•18 °C to 28 °C (64 °F to 82 °F) for voltage and resistance measurements
•21 °C to 26 °C (70 °F to 79 °F) for current measurements
•0% to 80% relative humidity
AC Current (21 °C to 26 °C) for CM-700*
Range Input Value Accuracy (50 to 60 Hz) Accuracy (60 to 400 Hz)
0.0 to 40.0 ±(1.9% + 0.7 A) ±(2.5% + 0.7 A)
400.0 A 40.0 to 200.0 ±(1.9% + 0.5 A) ±(2.5% + 0.5 A)
200.0 to 400.0 ±(3.0% + 0.5 A) ±(3.6% + 0.5 A)
600 A 400 to 600 ±(1.9% + 10 A) ±(2.5% + 10 A)
AC Current (21 °C to 26 °C) for CM-750**
Range Input Value Accuracy (50 to 60 Hz) Accuracy (60 to 400 Hz)
0.0 to 40.0 ±(1.9% + 0.7 A) ±(2.5% + 0.7 A)
400.0 A 40.0 to 200.0 ±(1.9% + 0.5 A) ±(2.5% + 0.5 A)
200.0 to 400.0 ±(3.5% + 0.5 A) ±(3.6% + 0.5 A)
600 A 400 to 600 ±(1.9% + 10 A) ±(2.5% + 10 A)
*CM-700 is average sensing, RMS calibrated.
**CM-750 is true RMS sensing. Accuracy is specified for sine waves at full scale and non-sine
waves below half scale. For non-sine waves, add the following crest factor corrections:
•Crest factor 1.4 to 2.0, add 1.0%
•Crest factor 2.0 to 2.5, add 2.5%
•Crest factor 2.5 to 3.0, add 4.0%
AC Voltage (18 °C to 28 °C) for CM-700* and CM-750**
Range Accuracy Frequency Response Input Impedance
400.0 mV Unspecified Unspecified
4.000 V ±(1.5% + 0.005 V) 40 to 300 Hz
40.00 V ±(1.5% + 0.05 V) 9 MΩ, 100 pF
400.0 V ±(1.5% + 0.5 V) 40 to 500 Hz
600 V ±(1.5% + 5 V)

CM-700 • CM-750
13
Accuracy (cont’d)
DC Current (21 °C to 26 °C)
Range Input Value Accuracy
0.0 to 40.0 ±(1.5% + 1.0 A)
400.0 A 40.0 to 200.0 ±(1.5% + 0.7 A)
200.0 to 400.0 ±(2.5% + 0.7 A)
600 A 400 to 600 ±(1.9% + 10 A)
Resistance (18 °C to 28 °C)
Range Accuracy Input Impedance
400.0 mV ±(0.7% + 0.2 mV)
4.000 V ±(0.7% + 0.002 V)
40.00 V ±(0.7% + 0.02 V) 9 MΩ
400.0 V ±(0.7% + 0.2 V)
600 V ±(0.7% + 2 V)
DC Voltage (18 °C to 28 °C)
*Reading may have ripple up to 6 digits near full scale.
**Reading may have ripple up to 3 digits near full scale.
†Response time approximately 20 seconds.
Maximum Hold
Accuracy of held value is stated accuracy from table + 10 digits per range change.
For example, a 100 VDC spike on a 200 mVDC signal requires 3 range steps to measure.
The addition to the accuracy specification is 3 x 10 digits on the 400.0 volt range or 3.0 volts.
Note: Maximum hold accuracy for resistance is specified on 400.0 Ω to 400.0 k Ω ranges only.
Range Accuracy
400.0 Ω±(1.2% + 0.6 Ω)*
4.000 kΩ±(0.9% + 0.003 kΩ)**
40.00 kΩ±(0.9% + 0.03 kΩ)**
400.0 kΩ±(1.2% + 0.3 kΩ)**
4.000 MΩ±(1.2% + 0.003 MΩ)**
40.00 MΩ±(2.5% + 0.05 MΩ)* †

14
Specifications
Display: 3-3/4–digit LCD (3999 maximum count)
Sampling Rate: 2 per second
Jaw Opening: 35 mm (1.38")
Overvoltage Protection Category: Category III, 600 V
Temperature Coefficient: 0.2 x (Accuracy) per °C above or below range specified in the
Accuracy section.
Operating Conditions:
0 °C to 30 °C (32 °F to 86 °F), 0% to 80% relative humidity, non-condensing
30 °C to 40 °C (86 °F to 104 °F), 0% to 75% relative humidity, non-condensing
40 °C to 50 °C (104 °F to 122 °F), 0% to 45% relative humidity, non-condensing
Note: Current measurement is limited to 40 ° C (104 ° F).
Indoor use only
Storage Conditions: –20 °C to 60 °C (–4 °F to 131 °F),
0% to 70% relative humidity, non-condensing
Remove battery
Elevation: 2000 m (6500') maximum
Pollution Degree: 2
Battery: One 9 V battery (NEDA 1604, JIS 006P, or IEC 6F22)
Battery Life: Approximately 150 hours with alkaline battery

CM-700 • CM-750
15
Overvoltage Installation Categories
These definitions were derived from the international safety standard for insulation
coordination as it applies to measurement, control, and laboratory equipment. These
overvoltage categories are explained in more detail by the International Electrotechnical
Commission; refer to either of their publications: IEC 1010-1 or IEC 60664.
Overvoltage Category I
Signal level. Electronic and telecommunication equipment, or parts thereof. Some examples
include transient-protected electronic circuits inside photocopiers and modems.
Overvoltage Category II
Local level. Appliances, portable equipment, and the circuits they are plugged into. Some
examples include light fixtures, televisions, and long branch circuits.
Overvoltage Category III
Distribution level. Permanently installed machines and the circuits they are hard-wired to.
Some examples include conveyor systems and the main circuit breaker panels of a building’s
electrical system.
Overvoltage Category IV
Primary supply level. Overhead lines and other cable systems. Some examples include cables,
meters, transformers, and other exterior equipment owned by the power utility.

16
Maintenance
1. Disconnect the unit from the circuit.
2. Remove the screw from the battery door.
3. Remove the battery door.
4. Replace the battery (observe polarity).
5. Replace the door and the screw.
Cleaning
Periodically wipe the case with a damp cloth and mild detergent; do not use abrasives or
solvents.
•Do not attempt to repair this unit. It contains no user-serviceable parts.
•Do not expose the unit to extremes in temperature or high humidity.
See Specifications.
Failure to observe these precautions can result in injury and can damage the unit.
Battery Replacement
Before opening the case, remove the test leads from the circuit and shut off the unit.
Failure to observe this warning can result in severe injury or death.

CM-700 • CM-750
17
Descripción
Los Medidores digitales con pinza modelos CM-700 y CM-750 de Greenlee son instrumentos
de verificación capaces de efectuar los siguientes tipos de mediciones: tensión alterna y
continua, corriente alterna y continua, y resistencia. Esta unidad es de bolsillo y cabe
perfectamente en la palma de la mano. También sirven para verificar continuidad. La pantalla
retiene una medición para verla más tarde o retiene la lectura máxima. El modelo CM-750 es
un multímetro de lectura de valores eficaces reales.
La pinza se adapta a conductores de hasta 35 mm (1,38 pulg.) de diámetro. Además, los
medidores incluyen lo siguiente:
• Selección automática de escala
• Tecla para ajuste en cero para amperios de CC
• Apagado automático seleccionable
• Protección de circuitos hasta 600 voltios
• Resolución de 100 mA hasta 400 amperios
Acerca de la seguridad
Es fundamental observar métodos seguros al utilizar y dar mantenimiento a las herramientas y
equipo Greenlee. Este manual de instrucciones y todas las marcas que ostenta la herramienta
le ofrecen la información necesaria para evitar riesgos y hábitos poco seguros relacionados
con su uso. Siga toda la información sobre seguridad que se proporciona.
Propósito de este manual
Este manual de instrucciones tiene como propósito familiarizar a todo el personal con los
procedimientos de operación y mantenimiento seguros para los Medidores digitales con pinza
modelos CM-700 y CM-750 de Greenlee.
Manténgalo siempre al alcance de todo el personal.
Puede obtener copias adicionales de manera gratuita, previa solicitud.
Greenlee y son marcas registradas de Greenlee Textron.
CONSERVE ESTE MANUAL

18
Importante Información sobre Seguridad
Lea y entienda este documento antes de manejar esta
herramienta o darle mantenimiento. Utilizarla sin comprender
cómo manejarla de manera segura podría ocasionar un accidente
y, como resultado de éste, graves lesiones o incluso la muerte.
Este símbolo se utiliza para indicar un riesgo o práctica poco segura que podría
ocasionar lesiones o daños materiales. Cada uno de los siguientes términos denota la
gravedad del riesgo. El mensaje que sigue a dichos términos le indica cómo puede
evitar o prevenir ese riesgo.
SÍMBOLO DE ALERTA
SOBRE SEGURIDAD
Peligros inmediatos que, de no evitarse, OCASIONARÁN graves lesiones o incluso la
muerte.
Peligros que, de no evitarse, PODRÍAN OCASIONAR graves lesiones o incluso la
muerte.
Peligro o prácticas peligrosas que, de no evitarse, PUEDEN OCASIONAR lesiones o
daños materiales.

CM-700 • CM-750
19
Importante Información sobre Seguridad
Peligro de electrocución:
• No aplique más del voltaje nominal entre dos terminales de entrada cualesquiera, o
entre una terminal de entrada cualquiera y una conexión a tierra.
• No toque las puntas de los cables de prueba ni ninguna parte del accesorio que
carezca de forro aislante.
De no observarse estas advertencias pueden sufrirse graves lesiones o incluso la
muerte.
Peligro de electrocución:
El contacto con circuitos activados puede ocasionar graves lesiones
o incluso la muerte.
Peligro de electrocución e incendio:
• No exponga esta unidad ni a la lluvia ni a la humedad.
• No utilice esta unidad si se encuentra mojada o dañada.
• Utilice cables de prueba y accesorios que sean apropiados para la aplicación que se
va a realizar. Consulte la información sobre categoría y voltaje nominal del cable de
prueba o el accesorio.
• Revise minuciosamente los cables de prueba o el accesorio, antes de utilizarlos.
Deberán estar limpios y secos, y su forro aislante deberá hallarse en buenas
condiciones.
• Utilícela únicamente para el propósito para el que ha sido diseñada por el fabricante,
tal como se describe en este manual. Cualquier otro uso puede menoscabar la
protección proporcionada por la unidad.
De no observarse estas advertencias pueden sufrirse graves lesiones o incluso la
muerte.

20
Importante Información sobre Seguridad
• No haga funcionar esta unidad con la caja abierta.
• Antes de abrir la caja, retire del circuito los cables de prueba (o la pinza), y apague
la unidad.
De no observarse estas advertencias pueden sufrirse graves lesiones o incluso la
muerte.
• No intente reparar esta unidad, ya que contiene partes que deben recibir
mantenimiento por parte de un profesional.
• No exponga la unidad a ambientes de temperatura extrema o altos niveles de
humedad. Consulte las Especificaciones.
De no observarse estas precauciones podrían sufrirse lesiones o daños a la unidad.
No cambie la función de medición mientras los cables de prueba estén conectados a
un componente o circuito.
De no observarse esta advertencia podrían sufrirse lesiones o daños a la unidad.
• A menos que vaya a medir tensión o corriente, apague y bloquee la energía.
Asegúrese de que todos los condensadores estén totalmente sin carga. No debe
haber tensión alguna.
• Al utilizar esta unidad cerca de equipo que genere interferencia electromagnética
quizá se obtenga una lectura inexacta e inestable.