Extech EX820A 1000A True RMS AC Clamp Meter with IR Thermometer

1. Introduction

The Extech EX820A is a professional 1000A True RMS AC Clamp Meter equipped with a built-in non-contact infrared thermometer. This device is designed for accurate electrical measurements and temperature monitoring in various applications, including electrical installations, motors, and other electrical devices. It features a large 6000 count backlit LCD display for clear readings and an ergonomically designed double-molded housing for comfortable, one-handed operation. The 43 mm (1.7 inch) jaw opening accommodates conductors up to 750 MCM or two 500 MCM cables. This meter is rated CAT IV-600 V for enhanced safety.

Safety Information: Always adhere to local and national safety codes. Use appropriate personal protective equipment. Do not attempt to measure voltages or currents exceeding the meter's specified limits. Ensure the meter is in good working condition before use. Refer to the safety section in the full manual for detailed precautions.

Figure 1: Extech EX820A Clamp Meter Overview

2. Product Features

• True RMS Measurement: Provides accurate readings for non-sinusoidal waveforms.
• 1000A AC Current Measurement: High current capacity for demanding applications.
• Built-in IR Thermometer: Non-contact temperature measurement with laser pointer for identifying hot spots.
• LoZ (Low Impedance) Mode: Prevents false readings caused by ghost voltages.
• Low Pass Filter (LPF): Ensures accurate measurements in electrically noisy environments.
• Inrush Current Measurement: Captures motor start-up current.
• CAT IV-600V Safety Rating: High safety standard for industrial environments.
• 6000 Count Backlit LCD Display: Large, easy-to-read display with illumination for dim lighting conditions.
• Jaw Opening: 43 mm (1.7 inches) for large conductors.
• Multimeter Functions: Includes AC/DC Voltage, Resistance, Capacitance, Frequency, Diode, and Continuity.

Figure 2: Display with LoZ and LPF Indicators

3. Setup

3.1 Unpacking and Inspection

Carefully unpack the meter and its accessories. Verify that all items listed in the 'Included Components' section are present and undamaged. If any item is missing or damaged, contact your supplier immediately.

3.2 Battery Installation

The EX820A requires one (1) 9V battery (included). To install or replace the battery:

1. Ensure the meter is turned OFF.
2. Locate the battery compartment cover on the rear of the meter.
3. Use a screwdriver to loosen the screw securing the battery cover.
4. Remove the cover and insert the 9V battery, observing correct polarity.
5. Replace the battery cover and tighten the screw.

3.3 Connecting Test Leads

For voltage, resistance, capacitance, frequency, diode, and continuity measurements, connect the supplied test leads:

• Insert the red test lead into the VΩHz+ input jack.
• Insert the black test lead into the COM input jack.

Figure 3: Included Components

4. Operating Instructions

The EX820A features a rotary function switch to select the desired measurement mode. Press the 'MODE' button to cycle through functions within a single switch position (e.g., AC/DC voltage, resistance/continuity).

4.1 Measuring AC Current (Clamp)

1. Set the rotary switch to the 'A~' position.
2. Open the clamp jaws by pressing the jaw release trigger.
3. Enclose a single conductor with the clamp jaws. Ensure the jaws are fully closed.
4. Read the AC current value on the display.

Figure 4: Measuring AC Current with the Clamp

4.2 Measuring AC/DC Voltage

1. Connect the test leads as described in Section 3.3.
2. Set the rotary switch to the 'V' position.
3. Press the 'MODE' button to select AC (V~) or DC (V–) voltage.
4. Apply the test probes to the circuit points where voltage is to be measured.
5. Read the voltage value on the display.

Figure 5: Measuring Voltage with Test Leads

4.3 Using the Infrared Thermometer

1. Set the rotary switch to the 'IR TEMP' position.
2. Point the meter's IR sensor (located at the top) towards the target surface. The laser pointer will assist in aiming.
3. Read the surface temperature on the display.

Figure 6: Using the Infrared Thermometer

4.4 LoZ (Low Impedance) Mode

The LoZ function is used to eliminate ghost voltages, which can cause misleading readings. When measuring voltage in circuits where ghost voltages are suspected, select the LoZ mode to provide a low impedance path that dissipates these stray voltages.

1. Set the rotary switch to the 'V LoZ' position.
2. Connect the test leads to the circuit.
3. Read the voltage. This reading will be more accurate in the presence of ghost voltages.

4.5 Low Pass Filter (LPF)

The LPF function is designed for accurate measurements on variable frequency drives (VFDs) and other electrically noisy equipment. It filters out high-frequency noise that can distort True RMS readings.

1. Set the rotary switch to the 'A~' or 'V~' position.
2. Press the 'LPF' button to activate the Low Pass Filter. The LPF icon will appear on the display.
3. Proceed with your current or voltage measurement.

4.6 Inrush Current Measurement

The Inrush function captures the maximum current surge when a motor or other inductive load starts up. This is useful for diagnosing motor starting issues.

1. Set the rotary switch to the 'A~' position.
2. Press the 'INRUSH' button. The meter will be ready to capture the inrush current.
3. Apply the clamp to the motor's power lead and start the motor. The meter will display the peak inrush current.

5. Maintenance

5.1 Cleaning

Wipe the meter with a dry, soft cloth. Do not use abrasives or solvents. Periodically clean the input jacks with a cotton swab and alcohol to ensure good contact.

5.2 Battery Replacement

Replace the 9V battery when the low battery indicator appears on the display. Refer to Section 3.2 for battery installation instructions. Always dispose of used batteries responsibly.

5.3 Storage

When the meter is not in use for an extended period, remove the battery to prevent leakage. Store the meter in a cool, dry place, away from direct sunlight and extreme temperatures.

6. Troubleshooting

• Meter does not power on: Check battery installation and ensure the battery has sufficient charge. Replace if necessary.
• No reading or 'OL' (Overload) displayed: Ensure test leads are properly connected and making good contact. Verify the measurement range is appropriate for the input. For current measurements, ensure only a single conductor is within the clamp jaws.
• Inaccurate readings: Check battery voltage. Ensure the correct function is selected. For voltage/current, consider using LoZ or LPF modes in noisy environments. Ensure proper contact with test points.
• IR Thermometer not working: Ensure the rotary switch is in the 'IR TEMP' position. Check for any obstructions to the IR sensor.

7. Specifications

8. Warranty and Support

8.1 Warranty Information

The Extech EX820A Clamp Meter comes with a 2-year warranty from the date of purchase. This warranty covers defects in materials and workmanship under normal use. It does not cover damage resulting from misuse, unauthorized modification, accident, or neglect. Please retain your proof of purchase for warranty claims.

8.2 Technical Support

For technical assistance, troubleshooting, or service inquiries, please refer to the official Extech website or contact Extech customer support. Contact information can typically be found in the full printed manual or on the manufacturer's website.