What is NCV?

NCV means different things in different fields. In the medical field, NCV refers to Nerve Conduction Velocity. In the electrical industry, it refers to Normally Closed Voltage.

Today, I will mainly introduce another definition of NCV: Non-Contact Voltage.

Part 1:The definition of NCV: Non-Contact Voltage

Definition: Non-contact voltage testing is a test method that detects whether the circuit or conductor under test is charged and the approximate voltage condition without direct physical contact with the circuit or conductor under test.

It is mainly based on the principle of electromagnetic induction. When there is an electric field around a charged conductor, the induction coil in the test instrument can sense the change in the electric field, thereby generating an induced electromotive force.

By analyzing, processing and converting this induced electromotive force, the instrument can determine whether the object under test is charged and estimate the approximate voltage range. In contrast to traditional contact voltage testing, this test method greatly reduces the risk of electric shock caused by direct contact during the test. It is also easy to operate and can play a role in a variety of complex environments and difficult-to-reach scenarios.

Part 2:Principle and development of NCV

In the field of electrical testing, non-contact voltage testing (Non-Contact Voltage) technology is gradually emerging and becoming a powerful assistant for many electricians and electrical enthusiasts. With its unique working principle and significant advantages, it provides us with a new, safer and more convenient way to deal with electrical problems.

Traditional voltage detection often requires the probe of the detection instrument to directly contact the conductor of the circuit or electrical equipment under test. This process may bring the risk of electric shock to the operator in some complex or dangerous electrical environments, especially when it is unclear whether the circuit is energized or there is a risk of insulation damage.

The non-contact voltage detection technology cleverly avoids this risk. Its core principle is based on the phenomenon of electromagnetic induction. When there is an electric field around a charged object, this electric field will produce an invisible "power line" distribution in space. The non-contact voltage detection tool is equipped with a highly sensitive induction coil. When the tool is close to a charged object, the electric field around the charged object will cause the magnetic flux in the induction coil to change.


According to Faraday's law of electromagnetic induction, the change in magnetic flux will generate an induced electromotive force in the coil. This weak induced electromotive force will be captured by the circuit system inside the detection tool and amplified, filtered, analyzed and processed in a series of ways. After a complex signal processing process, the detection tool can determine whether there is voltage based on the pre-set algorithm, and intuitively present the detection results to the user through sound and light alarms, display screens, etc.NF-8209S Non-contact Voltage Tester

Part 3: Application scenarios of NCV

Household Applications

  • Appliance Repair and Detection: When household appliances such as televisions, refrigerators, and washing machines malfunction, non-contact voltage testers can be used to detect whether the plugs, wires, and internal circuits of the appliances are electrified. This helps repair personnel quickly locate the scope of the fault and determine whether there are abnormal voltages or circuit interruptions. Moreover, it eliminates the risk of accidental contact without the need to disassemble the appliance casings.NF808 NCV Feature
  • Wire Inspection: During home decoration and wiring processes, it can be used to locate the electrified wires buried in walls, determine the routing and position of the wires, and prevent accidental drilling or nailing into the wires, which could cause safety accidents. It can also detect whether there are electrical leakage problems in the wires to ensure the safety of household electricity use.
  • Distinguishing between Live and Neutral Wires: Non-contact voltage test pens can conveniently detect the live and neutral wires in sockets. When detecting the live wire, there will be an audible and visual alarm, while there will be none when detecting the neutral wire. This provides convenience for the correct wiring of household electricity and fault 

Industrial Field

  • Equipment Maintenance and Fault Diagnosis: It can be used to detect the voltages of industrial equipment such as motors, transformers, switch cabinets, and frequency converters to ensure their normal operation and performance. Through non-contact measurement, it is possible to quickly detect the voltage situation while the equipment is in operation, promptly discover potential electrical problems such as voltage fluctuations, phase loss, and overload, improve maintenance efficiency and equipment reliability, and reduce downtime and production losses.
  • Power Transmission and Distribution Monitoring: In the power system, it can be used for voltage monitoring and fault diagnosis of transmission lines, substation equipment, and distribution networks. Power engineers can use non-contact voltage testing equipment to obtain voltage information in real time without affecting power transmission, judge the operating state of the power system, and promptly detect and handle abnormal voltage situations to ensure the reliable power supply of the power system.NF-8506 NCV Function
  • Production Line Inspection: For the electrical equipment and circuits in automated production lines, non-contact voltage testing can conduct quick inspections without shutting down the production lines to check whether the voltages of the equipment are normal and ensure the stable operation of the production lines and improve production efficiency.

Therefore, a test tool with NCV function is essential. Whether you are a home user or a non-professional, your safety is guaranteed with it.NF-8209s is worth recommending! It uses advanced electromagnetic induction technology to accurately detect voltage at a safe distance. It is extremely easy to operate without touching the conductor, and can easily cope with various complex environments and hard-to-reach places.

Whether it is home line inspection, electrical appliance repair, or daily maintenance and fault diagnosis of industrial equipment, it can show its prowess. It is small and portable, easy to carry and use. Its clear display and intuitive operation interface allow users to quickly obtain voltage information and effectively improve detection efficiency. It is a powerful assistant in the field of electrical detection. And it has more than just NVC function, for more functions, see:


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