Product May. 14, 2014

Hioki Launches Clamp On Power Logger PW3365-20

World’s First Non-Contact Solution for Safe, Accurate Power Measurement

Nagano, Japan

Hioki E.E. Corporation is pleased to announce the launch of the Clamp On Power Logger PW3365-20, the world’s first instrument capable of measuring power safely and accurately without requiring the operator to make contact with a metal conductor.

Hioki developed the PW3365-20, the world’s first power meter to allow operators to measure voltage safely and accurately simply by clamping a sensor around an insulated wire, in response to the needs of customers who wish to measure power more safely. By equipping a power meter with a non-contact voltage sensor, the company has made it possible to avoid the risk of short-circuits and electric shock when measuring voltage by conventional means.

Development Background and Process
Currently, many companies are working to save energy, creating new opportunities for measuring power consumption. In the past, power measurement in settings such as large factories was overseen by workers with electrical knowledge and experience. However, as companies across the entire spectrum of sizes and industries are driving up the need for power measurement, such measurement is being increasingly carried out by workers who lack adequate knowledge and experience. Consequently, demand for products that enable power to be measured safely has been rising.

Against this backdrop, Hioki began developing a new product that takes a new approach to power measurement.

Advantages of Non-Contact Power Measurement
Dramatically improved safety
Clamp-style power meters have entered into widespread use in the field of power measurement. These instruments already had the ability to measure current using clamp-on sensors, allowing measurements to be made safely from outside insulated wires. However, operators have typically had to connect clips to the metal terminals of circuit-breakers or other components in order to measure voltage. This approach poses the risk of a short-circuit if the technician mistakenly allows one of the metal clips to come into contact with the adjacent metal terminal as well as the risk of electric shock if he or she inadvertently touches an exposed metal conductor.

Prior to the launch of the PW3365-20, Hioki launched the Safety HiTester 3258, a non-contact voltmeter, in 2008. By applying the measurement technology used in the 3258, the company was able to develop a sensor capable of safely measuring the voltage in an insulated wire from outside the insulation. In this way, the PW3365-20 delivers a dramatically higher level of safety to operators by delivering non-contact measurement capability for current, voltage, and power.

Measurement Principles of the World’s First Non-contact Voltage Sensor
The Voltage Sensor PW9020 used by the PW3365-20 is able to perform non-contact measurement by means of the principle described below.

Inside the PW9020 is a metal plate that serves as an electrode, and when this electrode detects a voltage (potential difference) in the object being measured, a minuscule current flows to it. By generating a voltage such that this current is eliminated, the sensor can accurately measure the voltage in the conductor.

Principal Applications
* Power management in factories and buildings
* Maintenance and management of electrical equipment


Established in 1935, HIOKI E.E. CORPORATION (TSE: 6866) has grown to become a world leader in providing consistent delivery of test and measuring instruments through advanced design, manufacturing, and sales and services. By offering over 200 main products characterized by safety and quality while meeting an expansive range of applications, we aim to contribute to the efficiency and value of our customers' work in research and development, production and electrical maintenance. HIOKI products and services are available around the world through our extensive network of subsidiaries and distributors. Information about HIOKI is available at

For more information, please contact:

Hioki PW3365-20 Clamp On Power Logger

Hioki's proprietary non-metallic contact voltage sensors