Greenlee CM-300 User manual

INSTRUCTION MANUAL
MANUAL DE INSTRUCCIONES
MANUEL D’INSTRUCTIONS
999 3265.2 © 1999 Greenlee Textron IM 1409 7/99
CM-300 • CM-310
CLAMP-ON AMMETERS
AMPERÍMETROS
CON PINZA
PINCES
AMPEREMETRIQUES
OFF 20A 200A 300A
AC Clamp Meter
Toggle
button
- Activate DH
- Activate PH
- Re-set
DH=Data hold • PH-Peak hold
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-300 and CM-310 Clamp-on Ammeters are hand-held test instruments
capable of measuring up to 300 amps of alternating current.
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 the Greenlee CM-300 and CM-310 Clamp-on Ammeters.
Keep this manual available to all personnel.
Replacement manuals are available upon request at no charge.
and are registered trademarks of Greenlee Textron.
KEEP THIS MANUAL

CM-300 • CM-310
3
Important Safety Information
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.
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.

4
Important Safety Information
• Do not operate with the case open.
• Before opening the case, remove the 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.
Using this unit near equipment that generates electromagnetic interference can result
in unstable or inaccurate readings.
Electric shock hazard:
Do not use the unit if it is wet or damaged.
Failure to observe this warning can result in severe injury or death.
Electric shock hazard:
Contact with live circuits can result in severe injury or death.

CM-300 • CM-310
5
Identification
1. Jaw
2. Lever
3. Toggle Button (CM-310 only)
4. Display
5. Selector
OFF 20A 200A 300A
AC Clamp Meter
Toggle
button
- Activate DH
- Activate PH
- Re-set
DH=Data hold •PH-Peak hold
1
2
3
4
5

6
Operation
1. Set the selector according to the Settings Table. Start with the highest measurement
range.
Settings Table
2. See Typical Measurements for illustrations of typical uses.
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, return the unit to Greenlee for repair.
4. Take the reading from the circuit to be tested. If the resolution is not satisfactory, remove
the meter from the circuit and change to the next lower range.
Notes (CM-310 Only):
• Press the Toggle button once for Data Hold. Hwill appear on the display. The present value
will remain on the display.
• Press the Toggle button again for Peak Hold. PH will appear on the display. The highest
value will remain on the display; the display will update when the meter measures a new
peak.
• Press the Toggle button again to return to normal mode.
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Electric shock hazard:
Contact with live circuits can result in severe injury or death.

CM-300 • CM-310
7
Typical Measurements
Clamp Around Line Splitter
Clamp Around Wire
OFF 20A 200A 300A
AC Clamp Meter
Toggle
button
- Activate DH
- Activate PH
- Re-set
DH=Data hold • PH-Peak hold
OFF 20A 200A 300A
AC Clamp Meter
Toggle
button
- Activate DH
- Activate PH
- Re-set
DH=Data hold • PH-Peak hold
Notes:
• Clamp the jaw around one conductor only.
• Close the jaw completely.
• Center the wire in the jaw for highest accuracy.
Notes:
• The Greenlee 93-30 Line Splitter is divided. One
section renders amps; the other renders amps
multiplied by 10.
• Close the jaw completely.
• Center the line splitter in the jaw for highest
accuracy.

8
Accuracy
See the Specifications section for operating conditions.
Accuracy is specified as follows: ±(a percentage of the reading + a fixed amount)
at 23 °C ±5 °C (73.4 °F ±9 °F), 0% to 80% relative humidity.
Accuracy Table
Specifications
Display: 3-1/2–digit LCD (1999 maximum count)
Sampling Rate: 3 per second
Overrange Indication: “1” appears on the display
Jaw Opening: 28 mm (1.10")
Low Battery Indication:
Overvoltage Category: Category III, 600 Volts
Protection Class: IP40
Operating Conditions: 0 °C to 40 °C (32 °F to 104 °F) , 0% to 80% relative humidity
Elevation: 2000 m (6500') maximum
Storage Conditions: –10 °C to 50 °C (14 °F to 122 °F), 0% to 80% relative humidity.
Remove battery.
Pollution Degree: 2
Battery: 9-Volt battery (NEDA 1604, JIS 006P or IEC 6F22)
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CM-300 • CM-310
9
1. Disconnect the unit from the circuit. Turn the unit OFF.
2. Remove the screws from the back cover.
3. Remove the back cover.
4. Replace the battery (observe polarity).
5. Replace the cover and screws.
Before opening the case, remove the jaw from the circuit and shut off the unit.
Failure to observe this warning can result in severe injury or death.
Battery Replacement

10
Greenlee Textron / Subsidiary of Textron Inc. 4455 Boeing Dr., Rockford, IL 61109-2988 815/397-7070