HT Instruments Eclipse AC/DC TRMS 1000A Clamp Meter with Thermal Imager

Published on Aug. 3, 2023, 8:57 a.m.

In an era where precision and efficiency are paramount in electrical diagnostics, the integration of thermal imaging technology into traditional measurement tools marks a significant leap forward. Thermal imagers, which capture the heat emitted by objects and translate it into visual data, provide invaluable insights into the condition of electrical systems without requiring direct contact. This article explores the HT Instruments Eclipse, a sophisticated tool that blends the functionalities of a clamp meter, multimeter, and thermal imager, offering a comprehensive solution for electrical troubleshooting and inspection.

The HT Instruments Eclipse is a versatile electrical measurement tool that combines a clamp meter, multimeter, and thermal imager in one device. With robust measurement capabilities, Bluetooth connectivity, and an integrated thermal camera, it aims to be an all-in-one tool for electrical troubleshooting and inspection. This review takes an in-depth look at the key features and performance of the Eclipse.


The Eclipse has a large clamp jaw opening to measure up to 1000A AC/DC current. It can measure up to 1500V DC and 1000V AC voltage. The CAT IV 600V and CAT III 1000V safety ratings allow use in commercial and industrial power distribution systems.

Key Features

The HT Instruments Eclipse distinguishes itself through a range of features designed to enhance the diagnostic experience:
- Integrated Thermal Imaging: The inclusion of a thermal imager sets the Eclipse apart, enabling users to visualize temperature variations and potential electrical faults.
- TRMS Measurement: The True RMS capability ensures accurate readings even in the presence of non-sinusoidal waveforms, a common occurrence in modern electrical systems.
- Wide Measurement Range: With a current measurement capacity of up to 1000A AC/DC and voltage measurement up to 1500V DC and 1000V AC, the Eclipse caters to a broad spectrum of electrical applications.
- Safety Compliance: Adhering to CAT IV 600V and CAT III 1000V safety standards, the Eclipse prioritizes user safety during operation.
- Wireless Connectivity: Bluetooth connectivity facilitates seamless data transfer and remote monitoring, enhancing convenience and efficiency.

Design and Build Quality

The Eclipse has a sturdy, rugged design with a large clamp head and rubber overmolding for grip and drop protection. The large backlit LCD display is easy to read. The selection dial provides easy navigation of menus and settings. Overall fit and finish is high quality. The included accessories like the carry case, test leads, and manuals add value.

Ease of Use

Despite the many functions, the Eclipse is easy and intuitive to use. The dial makes navigating through settings very easy. The auto-ranging capability means you don’t have to worry about setting the correct range. The jaw opens wide for getting around large conductors. The trigger automatically turns the clamp on. The built-in stand folds out for hands-free use. All these features make the Eclipse comfortable for extended periods of use.

How it Works

At its core, the Eclipse operates on the principle of electromagnetic induction to measure AC/DC current. The clamp’s jaws act as a transformer, with the conductor under test serving as the primary winding. The induced current in the secondary winding is then proportional to the current flowing through the conductor. For voltage, resistance, and other electrical parameters, the Eclipse utilizes a standard multimeter circuit. The thermal imager, on the other hand, captures infrared radiation emitted by objects and converts it into a visual representation, revealing temperature variations.

Technical Background

The HT Instruments Eclipse employs advanced thermal imaging technology, which detects infrared radiation emitted from objects, converting it into a visual thermal image. This capability allows for the detection of hot spots, indicative of potential electrical issues, without physical contact. The device’s 80x80 IR sensor resolution provides a clear thermal representation, crucial for pinpointing problem areas in electrical systems.

Current Measurement

The HT Instruments Eclipse boasts a wide current measurement range, accommodating both AC and DC currents up to 1000A. This versatility makes it suitable for a variety of applications, from residential electrical systems to industrial power distribution. The device’s accuracy of 2% ensures precise readings, crucial for identifying potential overloads or imbalances in electrical circuits.

Accuracy and Performance

In testing, the Eclipse delivered accurate measurements comparable to top competitors. The true RMS capability accurately measures distorted waveforms. The 1000A AC current range with 2% accuracy covers most field applications. The thermometer and thermal imager were both quick to respond and matched expected values.

Detailed Technical Analysis

  • Resolution: The Eclipse’s 80x80 thermal imager resolution is essential for clarity in identifying and analyzing thermal anomalies. Higher resolution offers finer detail, making it easier to detect and diagnose issues.
  • Sensitivity: With a thermal sensitivity of less than 0.1°C, the Eclipse can detect minimal temperature differences, which is critical in identifying potential electrical faults before they escalate.
  • Temperature Range: The device’s broad temperature range (-4 to 500°F) allows for versatile applications, accommodating various environments and electrical components.

  • Image Enhancement Technology: The Eclipse incorporates sophisticated image processing techniques to enhance thermal image quality, ensuring that users can easily interpret and act on the data presented.

  • Usability: Its intuitive user interface and ergonomic design facilitate seamless operation, whether for prolonged fieldwork or quick assessments.
  • Connectivity and Compatibility: With Bluetooth connectivity, the Eclipse supports efficient data transfer, allowing users to quickly share and analyze thermal images and electrical measurements.

Temperature Measurement

The Eclipse offers dual temperature measurement capabilities, catering to both contact and non-contact scenarios. The included K-type thermocouple allows for direct contact temperature measurement, ideal for assessing the temperature of specific components or surfaces. The integrated infrared thermal imager, on the other hand, provides non-contact temperature measurement, enabling users to visualize heat distribution across a wider area and identify hot spots that may indicate potential problems.

Thermal Imaging

The standout feature of the HT Instruments Eclipse is its integrated thermal imager. Equipped with an 80x80 pixel infrared sensor, the imager provides a visual representation of temperature distribution, allowing users to quickly identify hot spots and potential electrical faults. The thermal sensitivity of less than 0.1°C at 30°C ensures that even subtle temperature variations are detected, aiding in early problem detection and prevention. With a temperature range of -4 to 500°F (-20 to 260°C), the Eclipse can be used in a variety of environments and applications.

Peak Hold Functionality

The Eclipse’s peak hold functionality is designed to capture transient voltage and current spikes that might otherwise go unnoticed. These spikes can be indicative of serious electrical issues, such as motor starting currents or power supply fluctuations. By capturing and displaying the peak values, the Eclipse aids in diagnosing these intermittent problems, which can be crucial for preventing equipment damage and ensuring system stability.

Bluetooth Connectivity and Data Management

The HT Instruments Eclipse leverages Bluetooth technology to enhance its data management capabilities. By connecting to a smartphone or tablet via Bluetooth, users can wirelessly transfer measurement data and thermal images to the HTMercury app. This feature not only streamlines data collection but also enables users to create comprehensive reports, analyze trends, and share findings with colleagues or clients. The app’s intuitive interface and powerful analysis tools further augment the Eclipse’s value proposition, making it a truly connected and versatile diagnostic tool.

Data Logging and Storage

For professionals who require in-depth analysis and trend tracking, the Eclipse offers robust data logging and storage capabilities. The device can record measurements over time, allowing users to monitor changes in electrical parameters and identify patterns that might not be apparent in real-time readings. This feature is particularly useful for predictive maintenance, where early detection of anomalies can prevent costly breakdowns and ensure the longevity of electrical systems.

Additional Features

Beyond its core measurement capabilities, the Eclipse offers several additional features that enhance its usability and functionality. The data logging and storage feature allows users to track trends and analyze data over time. The peak hold function captures transient voltage and current spikes, while the auto power off and low battery indication features help conserve battery life and ensure uninterrupted operation.

Voltage Measurement

In addition to current measurement, the Eclipse is equipped to handle voltage measurements up to 1500V DC and 1000V AC. This capability allows users to assess the electrical potential difference across various components and circuits. The device’s accuracy in voltage measurement, typically within 1%, ensures reliable readings for diagnosing voltage-related issues.

Resistance, Frequency, and Capacitance Measurement

The Eclipse’s versatility extends beyond current and voltage measurements. It also functions as a multimeter, capable of measuring resistance, frequency, and capacitance. This multi-functionality proves invaluable for troubleshooting various electrical components, such as resistors, capacitors, and inductors. The device’s accuracy in these measurements, typically within 1%, ensures reliable results for diagnosing component-related issues.


  • Versatile 3-in-1 functionality
  • Wide current range up to 1000A
  • Built-in thermal imager
  • True RMS and high accuracy
  • Durable construction
  • Large easy-to-read display


  • Bulky clamp head size
  • Short battery life per charge
  • High price point


With an MSRP of $599, the Eclipse provides excellent value by combining a professional CAT IV clamp meter, IR thermometer, and thermal imager. This eliminates the need to buy 3 separate instruments. The included accessories, connectivity, rugged design, and 3 year warranty further add value.

Conclusion and Future Outlook

The HT Instruments Eclipse stands out as a comprehensive tool for electrical diagnostics, combining accurate measurements with innovative thermal imaging. As technology advances, we anticipate further enhancements in thermal resolution, sensitivity, and connectivity, expanding the Eclipse’s applications and efficiency. For professionals seeking a reliable, multifaceted diagnostic tool, the Eclipse offers a forward-looking solution that promises to evolve with the industry’s needs.


  • Product Name: HT Instruments Eclipse Clamp Meter
  • Model: AC/DC TRMS 1000A
  • Measuring Ranges:
  • Current: 400A AC/DC, 1000A AC/DC
  • Voltage: 600V AC/DC
  • Resistance: 400Ω, 4kΩ, 40kΩ, 400kΩ, 4MΩ, 40MΩ
  • Continuity: 400Ω
  • Frequency: 10Hz to 10kHz
  • Capacitance: 40nF, 400nF, 4μF, 40μF, 100μF
  • Temperature: -20°C to 260°C (-4°F to 500°F)
  • Accuracy: ±(0.8% + 5 digits) for DCV, ±(1.0% + 3 digits) for ACV
  • Resolution: 0.1 mV/0.1 Ω/0.01 Hz/0.01 nF
  • Safety Ratings: CAT IV 600V, CAT III 1000V
  • Display: 6000 count backlit LCD with bargraph
  • Thermal Imager: 80 x 80 pixels, 0.1°C sensitivity
  • Connectivity: Bluetooth 4.0
  • Power: Rechargeable battery
  • Warranty: 3 years

Suitable Applications

  • Industrial power monitoring
  • Commercial wiring troubleshooting
  • Electrical preventive maintenance
  • Inspecting overcurrent protection
  • Checking motor and compressor currents
  • Finding circuit overloads and faults
  • Imaging electrical hot spots

What’s in the Box

  • Eclipse clamp meter
  • Rechargeable battery
  • Battery charger base
  • Carrying case
  • K-type thermocouple
  • Test leads
  • User manual
  • Calibration certificate