Electrical work is always fraught with danger of electric shock. For this reason, specialists, in addition to training and periodic training, undergo many briefings and inspections. However, there are situations when the repair or maintenance of a home power network has to be done by a home foreman who does not have experience in such work. In this case, the voltage indicator becomes the main device that will be necessary for the beginning electrician. Similar devices, from simple to more complex, are used by professionals. It is on it that it is worth dwelling in detail today.
What is a similar device and how does it work
The network voltage indicator is a device that allows you to determine the presence of current on the contacts. The main objective of the device is to ensure the safety of an electrician. Depending on the type of indicator, it can indicate the presence of a linear or phase voltage (between two contacts), and when it contacts one of the terminals. Also, such devices can be non-contact - similar indicators are able to determine the presence of current even when it passes through hidden wiring in the wall.
The problem with many such devices is that they show guidance currents, which sometimes interferes with the determination of the phase conductor. However, with the right choice of the device and the ability to use it, the indicator will become an indispensable assistant for the home master.
Types and types of devices for determining the presence of voltage
Such devices can be divided by classification - these are unipolar and bipolar devices (professional probes). In the order of measurement, they can be contact or non-contact. Also, current and voltage indicators differ in the type of user alert element. It could be:
- battery-powered LED;
- neon;
- LCD display.
As an additional control of the network status, an audio buzzer is installed. The cheapest devices are indicators with a neon element. Their main disadvantage is a faint glow. With insufficient natural or artificial lighting, such an indication is quite problematic to discern.
The most common among homemasters are ordinary voltage indicator screwdrivers, which can be equipped with a neon lamp, an LED element or a liquid crystal display. It is on them that it is worthwhile to dwell in more detail.
Home appliances
You should start with a cheaper option - a screwdriver with a neon indication. Despite the insufficient lamp glow, such devices are deprived of the ability to capture guidance currents, which increases the accuracy of measurements. However, it is worth noting that the integrity of the circuit with such a device cannot be checked. In order to find out if a surface or a bare conductor is energized, you should touch it with the tip of a screwdriver and attach a finger to the metal platform at its rear. If there is a phase, the lamp will light.
A slightly more functional device can be called a voltage indicator on the LEDs. This device is equipped with batteries, which allows you to check the integrity of the circuit. The glow of the elements is brighter and more noticeable, and when checking the phase, touching the platform is optional. The problem with this indicator is to capture guidance currents, but sometimes it can help. For example, when making repairs or when you need to drill a hole in the wall. To do this, take the LED voltage indicator for the sting and guide it along the wall. In the place of wiring under the plaster, the LED will light up.
The most accurate amateur device is a screwdriver indicator, equipped with a liquid crystal display. In addition to the presence of a phase, the applied voltage will be displayed on the screen. The minus of the device in the absence of backlight, which does not allow it to be used in the twilight, not to mention the darkness.
Contactless indicators for checking the presence of voltage
Such devices have proven themselves not from the best side. Of course, they increase the safety of the user, additionally protecting him from electric shock, however, it will not be possible to verify which of the conductors is phase and which is zero with a similar device due to interference. All he can do is show the home master if there is voltage in a particular cable.
To carry out repairs on the home, experts advise you to purchase a non-contact voltage indicator only as an auxiliary tool and use it along with conventional devices for testing. With its help, it is quite convenient to specify the location of the wiring routes hidden under the wallpaper and a layer of plaster.
Multifunction devices and their application
Such digital voltage indicators are called testers or multimeters. These are complex devices that can determine the presence in the network of not only alternating, but also direct current, its strength, circuit resistance. All data is displayed on a liquid crystal display, which can be equipped with a backlight. Testers can also use a home master without experience, however, for this it is necessary to understand the position of the switch on the case, which is set depending on the operation being performed. In addition, you should have certain knowledge necessary in the production of measurements.
For example, everyone knows that checking the voltage involves connecting the probes in parallel (one per phase, the second to zero). If it is necessary to measure the current strength, then serial switching is necessary. Otherwise, the device will simply fail. And there are many similar nuances when using the multifunctional digital voltage indicator.
Two-pin network testers
Such devices are already considered professional, although their domestic use is also quite common. On one of the probes connected by a wire, there is a light bulb or a liquid crystal display. Such a voltage indicator requires the presence of a phase and a zero (in the 220 V network) or two voltage contacts (at 380 V). In this case, the voltage at the tested terminals must have a sinusoid with a shift. Simply put, you can check the voltage only between the opposite phases. If the neutral conductor burns out in the junction box of the apartment and voltage is applied to it, the bipolar indicator will not show the presence of current.
As a similar device, many use a test lamp, the wires from the cartridge of which are used as probes. However, this verification method is unsafe. A conventional lighting device is designed for a voltage of 220-240 V. When the zero breaks and closes it to a phase that has a shift relative to the main one, 380 V will be supplied to the lamp, as a result of which it will simply explode, which could result in personal injury. In addition, in such circuits, no limiting resistors are used, which can lead to electric shock when one probe comes into contact with a live contact, and the second with an unprotected part of the human body.
The bipolar voltage indicator is quite convenient when used in the installation and maintenance of switchboards. The device allows you to check the performance of not only phase and zero contacts, but also the grounding bus. At the same time, the convenience of working with it will depend on the length of the wire connecting the probes.
High-voltage indicators: the nuances of use
Such devices are called high voltage indicators (IOC). They are used in the maintenance and repair of electrical installations with a rating of 400 V to 10 kV. Outwardly, such an indicator of current and voltage looks like a long rod with a handle equipped with a restrictive ring to prevent slipping of the hand in the direction of live parts. The device consists of:
- A contact element that is in contact with the bus.
- A gas discharge or LED lamp indicating the presence of voltage.
- A special window through which you can see the glow.
- An insulated rod between the handle and the contact part. Its length can be constant or adjustable.
Interesting information! None of those on duty will sign a permit for servicing a transformer substation, if the tool kit of electricians does not have a high-voltage indicator and protective equipment for working with it (rubber gloves, dielectric bots, rug).
Such devices are not used for household power networks with a voltage of less than 0.4 kV. Modern devices are more high-tech and can be equipped with a unit with a liquid crystal display and a certain amount of memory. By measuring the performance at different phases of several transformers, you can analyze the information received later, in a calm environment and understand what actions need to be taken.
Vehicle voltage control devices
For such purposes, devices are manufactured that can operate at 12 V or 24 V. The on-board voltage indicators always have 2 probes - it will not work in a different way to check the car's network. The notification for such devices can be different - LEDs, incandescent lamps or a liquid crystal display. Also quite convenient in this regard are multifunctional indicators that can be set to a constant voltage of small values.
The on-board network is an area in which the use of warning lights as an indicator of vehicle voltage is allowed. Sudden jumps are excluded here, which eliminates the danger of a glass bulb exploding. However, protection is still necessary. A light bulb crashed on metal elements can injure a person.
DIY voltage indicator
Making the simplest device for checking the phase yourself is quite simple. To do this, you will need:
- socle from a burned-out lamp (E14 or E27);
- length of cable channel;
- a resistor with a resistance of 0.47-1 mOhm;
- LED or neon light;
- ordinary nail 50-70 mm long;
- soldering iron, electrical tape, wire, hot glue.
The algorithm for the production of work is as follows. Details are arranged sequentially - a nail, a resistor, a lamp. They solder among themselves. A contact platform disassembled from the base is soldered to the remaining free contact of the LED or lamp. Connections can be made directly, but it is much more convenient if this is done by pieces of wire. Such installation will increase freedom of action when placed in the case.
Then, opening the cable channel cover, the assembled circuit is carefully laid inside so that on one side, from the end, there is a contact area, and a nail sticks out from the second. After placement, the parts are fixed using hot melt adhesive. A hole is made in the lid through which you can see the lamp. It remains only to fix the case and isolate part of the nail, leaving it exposed no more than 1.5 cm. Thus, without any extra time and money, you can independently assemble a voltage indicator.
Indicator lamp for checking the vehicle electrical system
Everything is much simpler here. An ordinary 12 V incandescent lamp, two pieces of wire, a soldering iron and electrical tape - that's all that is required for its manufacture. Flexible copper conductors are soldered to the contacts of the base, after which they are isolated. It also does not hurt to cover the contact ends with a layer of tin or use small nails instead of probes. Verification is as follows. One of the probes is connected to the frame, the car body or the negative terminal of the battery. Care should be taken to ensure good contact, which can be prevented by a coat of paint. The second probe checks the contacts. In contact with a point carrying a positive charge, the lamp will glow.
It is also easy to make a device for monitoring the integrity of the electric circuit, popularly referred to as the "arch." To do this, it will be rational to use the LED from the lighter. If sound notification is required, a good device can be made from a children's toy. To do this, the power button is disassembled, instead of which 2 wires with probes are connected. In this case, when the buzzer or LED is shorted, voltage from the batteries will be applied. Such probes can be used to check the windings of electric motors, spirals of heating elements or various microcircuits.
Is it reasonable to make such devices yourself
Based on the cost, it’s a little more convenient to purchase the simplest indicator screwdriver in the store. Doing work with your own hands is justified only if the home master has a desire to do such things and free time. As for high-voltage voltage meters, the independent manufacture of such devices is strictly prohibited. It is impossible to calculate the degree of protection here. Moreover, if it is insufficient, it is possible to form an electric arc between the transformer bus and the rod. Even with protective equipment, such a discharge can cause many problems. Given that its brightness and temperature are much higher than the welding arc, it is easy to imagine which burns of the mucous membranes of the eyes can be obtained.
Final part
Every home foreman is required to be able to use voltage indicators, regardless of his education. These are pretty useful tools that make troubleshooting your home electrical network easier. Which type of device to choose is for everyone to decide. The main thing is compliance with safety rules when using it.