Voltage / Continuity and Non-Contact Testers
Voltage and Continuity Testers and also Non-Contact Voltage and Current Detectors are some of the most basic electrical circuit testing tools
Voltage and Continuity Testers
Voltage and Continuity Testers can be as simple as a small light or buzzer connected to a plastic housing, with a battery and the two test leads completing the circuit. If the circuit you are testing has a path for electricity to flow, then the light/buzzer will activate, letting you know that the circuit is good. Otherwise one can assume that there is a break or fault within the circuit you are testing.
These devices can also specify what voltage you are in, not an exact measurement, like a multimeter but a common range, either 120 or 220, for example. These testers are much more prevalent in industrial applications where there are multiple voltage ranges in any area.
A continuity tester determines if an electrical circuit can be made between two points. There are two main types: solenoid testers and full-featured testers. Solenoid testers are the traditional model. Full-featured testers perform multiple functions and come with features that make the user’s job easier.
Continuity testers are used in residential, industrial, and commercial environments. They are used in a variety of applications, including electricians, cable TV and audio, alarm technicians, HVAC installers, auto repair technicians, and DIY homeowners. They come in various styles and sizes to meet a range of needs.
Continuity Testers Applications
- Measure volts ac and volts dc
- Troubleshoot low-voltage lighting
- Detect live voltage even when the batteries are dead
- Test GFCI circuits
- Resistance measurement
- Check the rotation of electrical motors
- Check the proper set up of 3-phase systems
- New home wiring
- Multiple cable and wire identification
- Local and remote continuity
- Home theatre installation
Types of Continuity Testers
- Traditional solenoid tester, also called Wiggy tester. Solenoid testers are extremely durable and easy to use. However, they have their limitations. For instance, they don’t work on low-voltage circuits. Solenoid testers get their name not because they are used to test solenoids but because they use a solenoid principle to operate.
- Full-featured tester. These testers are capable of testing and measuring multiple parameters and come with features, such as a built in flashlight, that make the user’s job easier.
Compare Solenoid Testers and Electronic Voltage Testers in this Fluke article:
Solenoid Testers vs. Electronic Voltage Testers
Key Features of Continuity Testers to Consider
- Continuity beeper
- 3 forms of ac/dc voltage indication: light, sound, and vibration for added user protection and convenience
- Detachable SlimReach™ probe tips are customized for national electrical standards
- CAT IV 600 V, CAT III 1000 V rated for added user protection
- Compliant with latest NFPA 70E recommendations
- Replaceable test probes for added flexibility and convenience
- Hazardous voltage warning light for added user protection
- Built-in flashlight
This video demonstrates Extech CT20 Remote & Local Continuity Tester and shows some of its many applications. It is just one of the continuity testers available.
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 Multimeters