
INSTRUCTION MANUAL HVAC Clamp Meter
True RMS
Measurement
Technology

| -328° – 2462°F -200° – 1350°C |
- MICROAMP DC
- INRUSH CURRENT
- NON-CONTACT VOLTAGE TESTING
- AUTO-RANGING
- TEMPERATURE
- AUDIBLE CONTINUITY
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CAT IV
600V
GENERAL SPECIFICATIONS
Klein Tools CL440 is an automatically ranging true root mean square (TRMS) digital clamp meter that measures AC current and inrush via the clamp, AC/DC voltage, DC microamps, resistance, continuity, frequency, capacitance, and tests diodes via test-leads, and temperature via a thermocouple probe.
- Operating Altitude: 6562 ft. (2000m)
- Relative Humidity: <95% non-condensing
- Operating Temp: 32° to 122°F (0° to 50°C)
- Storage Temp: 14° to 122°F (-10° to 50°C)
- Accuracy: Values stated at 65° to 83°F (18° to 28°C)
- Temp Coefficient: 0.1 × (Quoted Accuracy) per °C above 28°C or below 18°C, corrections are required when the ambient working temp is outside of Accuracy Temp range
- Dimensions: 10.04″ × 3.77″ × 1.57″ (255 × 96 × 40 mm)
- Weight: 14.22 oz (403 g) including batteries
- Calibration: Accurate for one year
- Auto Power-Off (APO): After approx. 10 minutes of inactivity
- Standards: IEC EN 61010-1, 61010-2-032, 61010-2-033.IEC EN 61326-1, 61326-2-2.
Conforms to UL STD.61010-1, 61010-2-032,61010-2-033; Certified to CSA STD.C22.2 NO. 61010-1, 61010-2-032,61010-2-033.
- Pollution degree: 2
- Accuracy: ± (% of reading + # of least significant digits)
- Drop Protection: 3.3 ft. (1m)
- Safety Rating: CAT IV 600V Class 2, Double insulation
CAT III: Measurement category III is applicable to test and measure circuits connected to the distribution part of the building’s low-voltage MAINS installation.
CAT IV: Measurement category IV is applicable to test and measure circuits connected at the source of the building’s low-voltage MAINS installation.
- Electromagnetic Environment: IEC EN 61326-1. This equipment meets requirements for use in basic and controlled electromagnetic environments like residential properties, business premises, and light-industrial locations.
Specifications subject to change.
ELECTRICAL SPECIFICATIONS
| Function AC Voltage | Range 600.0mV | Resolution 0.1mV | Accuracy +(1.8% + 5 digits) |
| 6.000V | 1mV | +(1.5% + 5 digits) | |
| 60.00V | 10mV | .+(1.2% + 5 digits) | |
| 600.0V | 100mV | ||
| 750V | 1V | +(1.5% + 5 digits) | |
| DC Voltage (V DC) | 600.0mV | 0.1mV | +(1.0% + 8 digits) |
| 6.000V | 1mV | ±(0.8% + 3 digits) | |
| 60.00V | 10mV | ||
| 600.0V | 100mV | ±(1.0% + 3 digits) |
Input Impedance: 10MΩ
Frequency Range: 45 to 400Hz
Maximum Input: 750V AC RMS or 600V DC
| AC Current (A AC) | 60.00A | 10mA | ±(2.5% + 10 digits) |
| 600.0A 100mA ±(2.0% + 10 digits) | 600.0A 100mA ±(2.0% + 10 digits) | 600.0A 100mA ±(2.0% + 10 digits) |
Frequency Range: 50 to 60Hz
| DC Microamps (µA DC) | 600 ‑ µA | 0.1 ‑ µA | ±(1.2% + 5 digits) |
Maximum Input: 750V AC RMS or 600V DC
| Resistance | 600.0Ω | 0.1Ω | ±(1.2% + 5 digits) |
| 6.000KΩ | 1Ω | ±(1.2% + 3 digits) | |
| 60.00kΩ | 10Ω | ||
| 600.0kΩ | 100Ω | ||
| 6.000MΩ | 1kΩ | ||
| 60.00MΩ | 10kΩ | ±(2.0% + 5 digits) |
Maximum Input: 750V AC RMS or 600V DC
ELECTRICAL SPECIFICATIONS
| Function | Range | Resolution | Accuracy |
| Capacitance | 60.00nF | 0.010nF | ±(4% + 25 digits) |
| 600.0nF | 0.100nF | ±(4% + 8 digits) | |
| 6.000μF | 0.001μF | ||
| 60.00μF | 0.010μF | ||
| 600.0μF | 0.100μF | ||
| 6.000mF | 0.001mF | ±(5% + 9 digits) |
Maximum Input: 750V AC RMS or 600V DC
| Temperature °F | -328° to 54°F | 1°F | ±(1.5% + 7 digits) |
| 55° to 2462°F | ±(1.2% + 6 digits) | ||
| -200° to 12°C | 1°C | ±(1.5% + 4 digits) | |
| Temperature °C | 13° to 1350°C | ±(1.2% + 3 digits) |
Maximum Input: 750V AC RMS or 600V DC
| Frequency | 10Hz to 60kHz | 0.001Hz to 0.01kHz | ±(0.1% + 5 digits) |
| Duty Cycle | 0.1% to 99.9% (≤10kHz) | 0.1% | ±1.5% (Range: 10% – 90%) |
Maximum Input: 750V AC RMS or 600V DC
OTHER MEASUREMENT APPLICATIONS
Maximum Input: 600V DC or 750V AC RMS
- Diode Test: Approx. 1mA, open circuit voltage ~3.0V DC
- Continuity Check: Audible signal <10Ω, max current 1.5mA
- Sampling Frequency: 3 samples per second
- Overload: “OL” indicated on the display
- Polarity: “-” on display indicates negative polarity
- Display: 3-5/6 digit, 6000 Count LCD
WARNINGS
To ensure safe operation and service of the meter, follow these instructions. Failure to observe these warnings can result in severe injury or death.
- Before each use verify meter operation by measuring a known voltage or current.
- Never use the meter on a circuit with voltages that exceed the category-based rating of this meter.
- Do not use the meter during electrical storms or in wet weather.
- Do not use the meter or test leads if they appear to be damaged.
- Use only with CAT III or CAT IV-rated test leads.
- Ensure meter leads are fully seated, and keep fingers away from the metal probe contacts when making measurements.
- Use caution when working with voltages above 25V AC RMS or 60V DC. Such voltages pose a shock hazard.
- To avoid false readings that can lead to electrical shock, replace batteries when a low battery indicator appears.
- Do not attempt to measure resistance or continuity on a live circuit.
- Always adhere to local and national safety codes. Use personal protective equipment to prevent shock and arc blast injury where hazardous live conductors are exposed.
- To avoid the risk of electric shock, disconnect leads from any voltage source before removing the battery door.
- To avoid the risk of electric shock, do not operate meter while battery door is removed.
SYMBOLS ON METER
| AC (Alternating Current) | AC/DC Current | ||
| DC (Direct Current) | Resistance (in Ohms) | ||
| Double Insulated Class II | Audible Continuity | ||
| Warning or Caution | Ground | ||
| Diode | Risk of Electrical Shock | ||
| Frequency | Capacitance | ||
| Duty-cycle | Voltage (Volts) | ||
| Temperature (Fahrenheit / Celsius) | Amperage (Amps) | ||
| Common | Non-Contact Voltage Tester | ||
| Duty cycle | Select | ||
| Backlight | Frequency | ||
| Positive | Negative |
SYMBOLS ON LCD
| AC (Alternating Current) | DC (Direct Current) | ||
| Negative Reading | Data Hold | ||
| Auto Ranging | Maximum Value Hold | ||
| Minimum Value Hold | Audible Continuity | ||
| Low Battery | Degrees (Celsius) | ||
| Degrees (Fahrenheit) | kilo (value × 103) | ||
| Mega (value × 106) | micro (value × 10-6) | ||
| milli (value × 10-3) | Volts (Voltage) | ||
| nano (value × 109) | Ohms (Resistance) | ||
| Amps (Amperage) | Farads (Capacitance) | ||
| Frequency/Duty Cycle | Auto Power-Off | ||
| Non-Contact Voltage Tester | Diode Test | ||
| Hazardous Voltage Indicator | Inrush |
FEATURE DETAILS

NOTE: There are no user-serviceable parts inside meter.
- 6000 count LCD display
- Function selector switch
- Clamp
- “COM” jack
- “VµA” jack
- Backlight button
- “RANGE” button
- “MAX/MIN” button
- Data Hold button
- Clamp trigger
- Arrow markings
- “SEL/NCV” button
- NCV Light
- NCV Sensing Antenna
- K-Type Thermocouple Inputs
- Temperature/Voltage input switch
- “InRush” Button
ON/OFF
To power ON the meter, rotate the Function Selector switch 2 from the OFF setting to any measurement setting. To power OFF the meter, rotate the Function Selector switch 2 to the OFF setting. By default, the meter will automatically power OFF after 10 minutes of inactivity. If the meter automatically powers OFF while in a measurement setting, press any button to power the meter ON, or rotate Function Selector 2 switch to OFF, then power ON the meter. To deactivate
the power OFF functionality press and hold the “SELECT” button 12 before powering ON from the OFF setting. When auto power OFF is deactivated, the Auto Power Off icon
will not be visible in the display.
SEL / NCV BUTTON (FOR NCV TESTING)
Press and hold the SEL/NCV button 12 to enter Non-contact Voltage Testing (NCV) mode to test for presence of AC voltage. The NCV icon and “EF” will be present on the display. Approach the conductor under test leading with the sensing antenna 14. In the presence of AC voltage, the red NCV light 13 will flash, audible signals (beeps) will
sound. Release the SEL/NCV button to exit NCV testing mode.
NOTE: Only voltages of 40V AC or greater will be detected.
BACKLIGHT Press Backlight button 6 to turn ON or OFF the backlight. The backlight does not automatically power OFF.
RANGE
The meter defaults to auto-ranging mode. This mode automatically determines the most appropriate measurement range for the testing that is being conducted. To manually force the meter to measure in a different range, use the “RANGE” button 7.
- Press the “RANGE” button
7to manually select the measurement range (is deactivated on the LCD). Repeatedly press the “RANGE” button7to cycle through the available ranges, stopping once the desired range is reached. - To return to auto-ranging mode, press and hold the “RANGE” button
7for more than two seconds (is reactivated).
MAX/MIN When the “MAX/MIN” button8is pressed, the meter keeps track of the Maximum and Minimum values.
- When measuring, press “MAX/MIN” button
8to toggle between the Maximum value (MAX), the minimum value (MIN). If a new maximum or minimum occurs, the display updates with that new value. - Press “MAX/MIN” button
8for more than two seconds to return to normal measuring mode.
DATA HOLD
Press HOLD 9 to hold the measurement on the display. Press HOLD9again to release the display to return to live measuring.
OPERATING INSTRUCTIONS
CONNECTING TEST LEADS
Do not test if leads are improperly seated. Results could cause intermittent display readings. To ensure proper connection, firmly press leads into the input jack completely.

TESTING IN CAT III MEASUREMENT LOCATIONS
Ensure the test lead shield is pressed firmly in place. Failure to use the CATIII / CATIV shield increases arc-flash risk.

TESTING IN CAT II MEASUREMENT LOCATIONS
CAT III / CAT IV shields may be removed for CAT II locations. This will allow testing on recessed conductors such as standard wall outlets. Take care not to lose the shields.

OPERATING INSTRUCTIONS
AC CURRENT (LESS THAN 600A)
AC Current is measured by pressing the clamp trigger 10 to open the clamp and place it around a current-carrying wire. When measuring, care should be taken to ensure that the clamp is completely closed with trigger 10 fully released and that the wire passes perpendicularly through the center of the clamp in line with the arrow markings 11.

NOTE: Current measurement can be made by clamping around single conductors, but not cables containing both live and neutral wires. In this case, a line splitter is required,
Klein Cat. No. 69409 is recommended.
To measure current:
- Rotate the Function Selector switch
2to the A~ setting. - Place clamp around wire. The current measurement will be shown in the display.
Disconnect test leads when measuring with the clamp.

AC/DC VOLTAGE (LESS THAN 600V)
1. Insert RED test lead into VΩµA jack 5, and BLACK test leads into COM jack 4 and rotate function selector switch 2 to the V
setting for AC or DC measurements. The meter defaults to AC measurement. To measure DC, press the “SELECT” button 12 to toggle between AC and DC modes. The AC or DC icon on the LCD indicates which mode is selected. Note “AC” or “DC” on the display.


OPERATING INSTRUCTIONS
Apply test leads to the circuit to be tested to measure voltage. The meter will auto-range to display the measurement in the most appropriate range.
NOTE: If “–” appears on the LCD, the test leads are being applied to the circuit in reverse. Swap the position of the leads to correct this. NOTE: To access mV range for V AC, the ‘RANGE’ button 7 must be used.
Manual Mode Sequence
| First Press | Second Press | Third Press | Fourth Press | Fifth Press | |
| AC Range | 0-750V | 0-600.0V | 0-60.00V | 0-6.000V | 0-600.0mV |
| DC Range | 0-60.00V | 0-6.000V | 0-600.0mV | 0-600.0V | 0-60.00V |
NOTE: When in a voltage setting and the test leads are open, readings of order mV may appear on the display. This is noise and is normal. By touching the test leads together to close the circuit the meter will measure zero volts.
INRUSH CURRENT
The Inrush feature captures starting current of a motor or transformer.
Starting current can assist in diagnosing a motor before it fails.
To measure inrush current:
- Rotate the Function Selector switch
2to the AC current A setting. - Place clamp
3around wire. The current measurement will be shown in the main display. - Press the InRush button
17to enter the Inrush mode and manually select 60A or 600A range by pressing the RANGE button7.Place the clamp around the compressor
start wire and turn the motor on. The starting current will hold on to the main display. The Inrush measurement period is 100-milliseconds. The secondary display measures running current. - Press InRush button
17to exit.

CONTINUITY
- Insert RED test lead into VΩµA jack
5, and BLACK test lead into COM jack4and rotate function selector switch2to the Continuity/Resistance/Capacitance/Diode-Test
setting.
NOTE: The meter defaults to Continuity testing in this mode. Ensure that the Continuity Testing icon
is visible on the display. If not, press the “SELECT” button 12repeatedly until the
icon is shown. - Remove power from circuit.
- Test for continuity by connecting conductor or circuit with test leads. If resistance is measured less than 10Ω, an audible signal will sound and display will show a resistance value indicating continuity. If a circuit is an open display will show “OL“.


DO NOT attempt to measure continuity on a live circuit.
µA DC CURENT (LESS THAN 600 µA)
- Insert RED test lead into VΩµA jack
5, and BLACK test lead into COM jack4and rotate function selector switch2to the µA
setting. - Remove power from circuit and open circuit at the measurement point.
- Connect test leads in series with the circuit.
- Apply power to the circuit to take the measurement.


DO NOT attempt to measure more than 600 µA.
RESISTANCE MEASUREMENTS
- Insert RED test lead into VΩµA jack 5, and BLACK test lead into COM jack
4and rotate function selector switch2to the Continuity/Resistance/Capacitance/Diode-Test
setting.
NOTE: The meter defaults to Continuity testing in this mode. Press the “SELECT” button12once to enter Resistance testing mode. The Resistance icon Ωwill appear on the display. - Remove power from circuit.
- Measure resistance by connecting test leads to circuit. The meter will auto-range to display the measurement in the most appropriate range.


NOTE: When in a Resistance setting and the test leads are open (not connected across a resistor), or when a failed resistor is under test, the display will indicate “O.L.” This is normal.
DO NOT attempt to measure resistance on a live circuit.
AC VOLTAGE + AC AMPERAGE FUNCTION
- Insert RED test lead into VΩµA jack
5, and BLACK test lead into COM jack4and rotate function selector switch2to the V+A~ setting.
- Press clamp trigger
13to open clamp3and place around the current-carrying wire. - The main display will show AC Voltage and the secondary display will show AC Amperage. Pressing the select button will reverse the displays; the main display will show AC Amperage and the secondary display will show AC Voltage
CAPACITANCE
- Insert RED test lead into VΩµA jack
5, and BLACK test lead into COM jack4, and rotate function selector switch 2 to the Continuity/Resistance/Capacitance/Diode-Test
setting.
NOTE: The meter defaults to Continuity testing in this mode. Press the “SELECT” button12twice to enter Capacitance testing mode. The Capacitance icon
will appear on the display. The meter should read 0 nF with test leads open. - Remove power from circuit.
- Measure capacitance by connecting test leads across the capacitor. The meter will auto-range to display the measurement in the most appropriate range.

DIODE TEST
- Insert RED test lead into VΩµA jack
5, and BLACK test lead into COM jack4and rotate function selector switch2to the Continuity/Resistance/Capacitance/Diode-Test
setting.
NOTE: The meter defaults to Continuity testing in this mode. Press the “SELECT” button12three times to enter Diode testing mode. The Diode icon
will appear on the display. - Touch test leads to diode. A reading of 200-800mV on display indicates forward bias, “OL” indicates reverse bias. An open device will show “OL” in both polarities. A shorted device will show approximately 0mV.


FREQUENCY / DUTY-CYCLE
- Insert RED test lead into VΩµA jack
5and BLACK test lead into COM jack4and rotate function selector switch2to the Frequency/Duty-CycleHz% setting.
NOTE: The meter defaults to Frequency testing in this mode. To enter Duty-Cycle testing mode, press the “SELECT” button12once. Ensure
that the appropriate icon (either Hz or %) appears on the display. - Measure by connecting test leads across the circuit.


TEMPERATURE
- Remove leads from meter and slide the temperature probe input switch
18to close jacks and expose the K-Type thermocouple ports. - Insert K-type thermocouple into port
15( and rotate function selector switch2to the Temperature
setting.
NOTE: The meter defaults to Fahrenheit scale in this model. To enter the Celsius scale, press the SEL button9. Ensure that the appropriate icon (either °F or °C) appears on the display. - To measure temperature, make contact between the thermocouple tip and the object being measured. When thermocouple tip and object are in thermal equilibrium, the measurement on the display will stabilize. The meter will auto-range to display the measurement in the most appropriate range.
Remove thermocouple before switching meter to other measurement functions.
The thermocouple included with the original purchase is suitable for temperatures below 356°F / 180°C only. To measure higher temperatures, a K-type thermocouple with the appropriate measurement range should be used.
MAINTENANCE
BATTERY REPLACEMENT
When
indicator is displayed on LCD, batteries must be replaced.
- Loosen captive screw and remove the battery cover.
- Replace 3 × AAA batteries (note proper polarity).
Replace the battery cover and fasten screw securely.
To avoid the risk of electric shock, disconnect leads from any voltage source before removing the battery door.
To avoid the risk of electric shock, do not operate meter while the battery door is removed.
CLEANING
Be sure the meter is turned off and wipe with a clean, dry lint-free cloth. Do not use abrasive cleaners or solvents.
STORAGE
Remove the batteries when a meter is not in use for a prolonged period of time. Do not expose to high temperatures or humidity. After a period of storage in extreme conditions exceeding the limits mentioned in the General Specifications section, allow the meter to return to normal operating conditions before using.
WARRANTY
DISPOSAL / RECYCLE
Do not place equipment and its accessories in the trash. Items must be properly disposed of in accordance with local regulations. Please see www.epa.gov or www.erecycle.org for additional information.
CUSTOMER SERVICE
KLEIN TOOLS, INC.
450 Bond Street
Lincolnshire, IL 60069
1-800-553-4676
[email protected]
www.kleintools.com
1390405 Rev 09/20 B





















