Indicators, testers

Indicator, phase meter, tester and probe in action. Types of indicators and their applications

An electrical indicator, also called a single-pole voltage tester, is a simple measuring instrument for checking the presence of alternating voltage in the range from 100 to 1000 V at frequencies from 50 to 500 Hz. Despite being a simple device, there are several main types of indicators with different devices and designs. They are also called phase testers, electrical phase meters, voltage testers or voltage indicators, voltage probes. An electrical indicator is a portable device that is designed to detect the absence or presence of voltage in the network or on the current-carrying elements of electrical installations. This check is carried out before connecting portable grounding or turning on the grounding knives, as well as before starting work on electrical installations. In these cases, it is not necessary to determine the voltage value, you only need to know its presence or absence.
The electrician's safety depends on the voltage indicator. Only after making sure that there is no voltage on the elements he will be working on can he begin working on repairing a lamp, switch or socket.

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Types of indicators

What types of indicators exist and how do they differ?
According to the measured voltage:

• Up to 1 kV
• Above 1 kV

Measuring testers up to 1 kV are divided according to the number of poles:

• Single-pole indicators
• Bipolar indicators

Universal indicators are divided according to the type of current measured:

• For alternating current
• For direct current

According to the type of indicator:

• Indicator with glow lamp
• Phase meter with LED indicator
• Digital indicator
• Non-contact indicator

Glim lamp indicator Simple indicators consist of a series-connected measuring tip, a small glim lamp for glow, a ballast resistor of 820 kΩ to 1 MΩ and a contact surface. Mechanically, an electrical indicator is often constructed in the shape of a screwdriver. The tip of a standard indicator (a screwdriver blade) constitutes the measuring tip and is used for measurement by placing it on the conductor under test or inserting it into the socket in the socket. The other end of the indicator should be lightly touched with a finger, then the electrical circuit is closed by the human body. If the conductor is live, the lamp will light up. The current flowing through the finger is usually of the order of microamperes and is safe for humans. When the tip of an indicator touches the neutral or earth conductor, the lamp does not light up, since they are at the same potential as the environment.
In principle, a standard indicator cannot be fully relied on, since the current flowing depends on the transition resistance between the contact and the skin of the finger. If the glim lamp lights up when in contact with a neutral or grounding conductor, it can be assumed that the electrical indicator is damaged. The measurement with an indicator is indicative and cannot be considered as proof of a quality grounding. To assess the grounding, it is necessary to measure the resistance of the loop. This is the so-called resistance of the tripping loop, a mandatory part of the measurement during the revision of electrical installations.

Indicators vs. two-pole voltage testers

Electrical indicators are not suitable for a definite and reliable measurement of voltage. Two-pole voltage testers are suitable for a reliable measurement of voltage. These devices are also safer, since no current flows through the human body during the measurement. A damaged indicator, for example with a defective ballast resistor, can cause an electric shock. Commonly available multimeters or installation testers can also measure voltage, but this is no longer just a voltage tester in the original sense of the word. As a minimum check of the functionality of any indicator, it is recommended to check its serviceability before each use. At the very least, this will show a defective indication.
Using an indicator to check sockets with so-called child protection is not applicable. A common design of this protection is a plastic strip hinged to the inside of the socket cover. To turn the fuse and free access to the contacts, insert the pins into both sockets at the same time. This is to prevent an unwanted object (such as a nail, screwdriver) from being inserted into one of the socket holes and causing an electric shock. The principle of this protection prevents the use of indicators. For such measurements, two-pole testers can be used. They often have a holder that holds the two tips at an axial distance of 19 mm, i.e. the distance between the contacts of ordinary European sockets.

Non-contact tester

Non-contact indicators detect an electric field in the immediate vicinity of the conductor using a sensor and signal it optically, for example with an LED diode. A battery is required for operation. With sufficient sensitivity, it is possible to detect voltage even in an insulated conductor. Non-contact indicators are suitable for checking alternating voltage, they are not applicable for direct current voltages. There is no separate standard for voltage indicators, they must comply with the general standard for measuring instruments BDS EN 61010-1 and 2. Some non-contact phase meters have both light and sound signaling

Types of indicators

They differ in design, source of light indication signal. Often, electrical specialists are interested in the following types:

• Professional testers
• Quality testers
• Digital testers
• Non-contact testers
• Sound testers
• LED testers
• Inductive tester

You can find indicators or single-pole voltage testers for checking the presence of alternating voltage in the range from 100 to 1000 V at frequencies from 50 to 500 Hz in our online tool store.

Some basic rules for working with an indicator

It is forbidden to use an incandescent lamp instead of a phase meter as a homemade voltage indicator. This lamp is dangerous and unreliable.
To find the phase of current-carrying elements or wires using a single-pole indicator, you need to take your indicator in your right hand, holding the dielectric handle, touch the blade to the tested wire or current-carrying element. In this case, your left hand should be placed behind your back so that it does not accidentally touch current-carrying elements or grounding. With the finger of your right hand, touch the metal contact of the single-pole indicator. It is more convenient to touch with your thumb.
If the glim lamp lights up, it means that the conductive element you are checking is under phase voltage. If the lamp does not light up, then there is zero or no voltage at all.
In the case of a two-pole indicator or voltage tester, the pin of the body where the indicator is located touches one contact of the tested element. The second pin touches the other contact - phase or zero. The absence or presence of voltage is determined by the intensity of the lamp. Using such a device is not at all difficult.

When checking voltage, it is necessary to work carefully and accurately, observing safety rules, as this is very dangerous to human life.
Customers who like products from the Indicators, Testers category often also buy similar products from the main Tools category .
The technical specifications of the products in the category Indicators, testers are subject to change without notice. The images of the products in the category are provided by manufacturers and distributors, but may sometimes be for informational purposes only. The current price means the manufacturer's or supplier's recommended retail price.

Indicator, phase meter, tester and probe in action. Types of indicators and their applications
Types of indicators
Indicator with glow lamp
Indicators vs. two-pole voltage testers
Non-contact tester
Types of indicators
Some basic rules for working with an indicator