Voltage indicators are portable devices that serve to establish the presence or absence of voltage on all kinds of live parts of mechanisms and devices, as well as elements of the electrical network.
Carrying out such checks is a vital undertaking, since when working on disconnected conductive elements, as well as finding damages to installations connected to the electric network, and taking measures to monitor the health of various power supply elements, there is a certain probability of people getting under voltage. In turn, voltage indicators are a means that can guarantee the safety of the health and life of people working in repair and maintenance services.
However, it should be borne in mind that such devices can only establish the fact of the presence of voltage, however, they cannot measure and show its value. Traditionally, voltage indicators are equipped with a light signal, which provides information on the presence of the desired value on live parts. However, using this simple, but very effective device, one can judge not only whether there is voltage on any one current-carrying part, but also say that there is no interphase voltage that can occur between two or more conductive elements.
Modern voltage indicators can be divided into two groups. The first includes devices for indicating the absence of the desired parameter in networks and installations up to 1000 Volts. The second can include all other protective equipment that are designed to work with electrical installations of more than 1 kV.
Let's consider each of them in more detail.
The low voltage indicator is a device widely used both in industrial and domestic conditions. Among modern means of protection up to 1 kV, single-pole and bipolar devices are distinguished. Their fundamental difference is in the principle of action: bipolar can show the presence of voltage between two current-carrying elements of an electrical installation, while a unipolar one needs contact with any one conductive part. It should also be noted that the first of the listed devices can be used in both AC and DC networks, while the second can only be used to determine the presence of AC. In the event of contact with a live DC power supply, a single-pole voltage indicator will show a false result. The presented pointers are recommended to be used for checking secondary voltage circuits, meters, fuses, switches and other elements of the electrical network.
The high voltage indicator is used for similar purposes in networks above 1 kV. These devices have a structure similar to protective equipment up to 1 kV and include a working, insulating and signal part. According to the rules of use, when working with such pointers, it is necessary to use dielectric gloves.