Non-Contact Voltage and Current Detectors
Non-Contact Voltage Testers (NCV Tester) test for energized circuits and defective grounds, whether for an industrial installation or a DIY (do-it-yourself) project around the house. The tip of the pocket-sized tester will indicate when within close proximity of an outlet, terminal strip, or power cord where voltage is present.
How does a Non-Contact Voltage Tester Work?
NCV Testers rely on capacitive current only and essentially detect the changing electric field around AC energized objects. In other words, no direct metallic contact with the circuit is required. However a non-contact tester that senses electric fields cannot detect voltage inside shielded or armored cables.
How to select a Non-Contact Voltage Tester
What type of alarm?
Most NCV testers feature a light or change of light (green to red) and a loud chirping noise or a buzzer when voltage is detected, but some models feature a vibration alarm in the meter, for louder environments.
What voltage range are you working in?
NCV testers typically detect voltages from 100V – 1000V. However, this varies. There are specific models that can range up to 120,000+VAC and some models detect voltages as low as 24V. Confirm the voltage ranges to select a model suitable for your work.
Current Tester
Though a much smaller demand, there are detectors available that aim to measure current over voltage. These can be extremely useful as they can detect current through shielded wires, conduit, junction boxes and even through walls, using adjustable sensitivities.
NCV Tester feature built into Multimeter
Many multimeters have a non-contact voltage detector feature capability. It adds to the convenience of having less to carry. See our Multimeter section for a choice of models at Products > Multimeters >
Handheld Multimeter