Voltage indicators - safety devices for people

Voltage indicators are portable devices that serve to establish the presence or absence of voltage on all kinds of current-carrying parts of mechanisms and apparatus, as well as elements of the electrical network.

Carrying out such inspections is a vital measure, since when working on disconnected conductive elements, as well as finding faults on installations connected to the power grid, and carrying out measures to control the serviceability of various power supply elements, there is a certain probability of people getting under tension. In turn, voltage indicators are a means that can guarantee the safety of the health and life of persons working in repair and maintenance services.

However, it should be borne in mind that such devices allow only to establish the presence of voltage, but can not measure and show its magnitude. Traditionally, voltage indicators are equipped with a light signal, which provides information on the presence of the desired value on live parts. However, by means of this simple but very effective device, one can judge not only whether voltage is present on any one current-carrying part, but also to say that there is no phase-to-phase voltage that can arise between two or more conductive elements.

Modern voltage indicators can be divided into two groups. The first include devices to indicate the absence of the desired parameter in networks and installations up to 1000 volts. The second can include all other means of protection, which 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 environments. Among the modern means of protection up to 1 kV, one-pole and two-pole devices are distinguished. The principal difference lies in the principle of action: bipolar can show the presence of a voltage between two current-carrying elements of the electrical installation, while a single pole requires contact with any one conductive part. It should also be noted that the first of these devices can be used in both AC and DC networks, while the latter can only be used to determine the presence of alternating current. In the case of contact with a DC network under voltage, a single-pole voltage indicator will show a false result. The presented indicators are recommended to be used for testing secondary voltage circuits, meters, fuses, switches and other elements of the electrical network.

The high voltage indicator is used for similar purposes in networks over 1 kV. These devices have a structure similar to the means of protection up to 1 kV and includes the working, insulating and signaling parts. According to the rules of use, when working with such indicators it is necessary to use dielectric gloves.