Electrical work is always associated with the danger of electric shock. It is for this reason that specialists, in addition to training and periodic advanced training, undergo many briefings and checks. However, there are situations when repairs or maintenance of the home power network have to be performed by a home master who does not have experience in such work. In this case, the main device that a novice electrician will need is a voltage indicator. Similar devices, from the simplest to the more complex, are also used by professionals. It is on it that we should dwell in detail today.
What is such a device and how does it work
Mains voltage indicator is a device that allows you to determine the presence of current on the contacts. The main task of the device is to ensure the safety of the electrician. Depending on the typeindicator, it can show both the presence of linear or phase voltage (between two contacts), and in contact with one of the terminals. Also, such devices can be non-contact - such indicators are able to determine the presence of current even when it passes through hidden wiring in the wall.
The problem with many of these devices is that they show guidance currents, which sometimes prevents the phase conductor from being detected. However, with the right choice of 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 classified according to the classification - these are single-pole and double-pole devices (professional probes). According to the order of measurement, they can be contact or non-contact. Also, current and voltage indicators differ in the type of user notification element. It could be:
- battery powered LED;
- neon;
- liquid crystal display.
An audible buzzer is installed as an additional control of the network status. The cheapest devices are indicators with a neon element. Their main drawback is a weak glow. With insufficient natural or artificial lighting, such an indication is quite problematic to make out.
The most common among home DIYers are ordinary voltage indicator screwdrivers, which can be equipped with a neon lamp, LED element orliquid crystal display. It is on them that it is worth dwelling in more detail.
Appliances designed for home use
You should start with a cheaper option - a neon indicator screwdriver. Despite the insufficient glow of the lamp, such devices are unable to capture induced currents, which increases the accuracy of measurements. However, it is worth noting that the integrity of the circuit cannot be checked with such a device. 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 put your finger on the metal platform at its back. If there is a phase, the lamp will glow.
A slightly more functional device can be called a voltage indicator on LEDs. This device is equipped with batteries, which allows you to check the circuit for integrity. The glow of the elements is brighter and more noticeable, and when checking the phase, it is not necessary to touch the platform. The problem with such an indicator is in capturing the guidance currents, but sometimes this can help. For example, when making repairs or need to drill a hole in the wall. To do this, take the LED voltage indicator by the sting and lead it along the wall. In the place where the electrical wiring is laid under the plaster, the LED will light up.
The most accurate amateur device is an indicator screwdriver 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 is the lack of backlight, which is notallows it to be used in dim light, not to mention darkness.
Non-contact voltage testers
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 check which of the conductors is phase and which is zero using such a device due to interference. All he can do is show the home master if there is voltage in a particular cable.
For home repairs, experts advise purchasing a non-contact voltage indicator only as an auxiliary tool and using it along with conventional test devices. With its help, it is quite convenient to specify the location of electrical wiring routes hidden under wallpaper and a layer of plaster.
Multifunctional instruments and their applications
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 current, but also direct current, its strength, and circuit resistance. All data is displayed on a liquid crystal display, which can be equipped with a backlight. A home master without experience can also use testers, 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 when making measurements.
For example, everyone knows thatvoltage test involves connecting the probes in parallel (one for phase, the second for zero). If you need to measure the current, then series switching is necessary. Otherwise, the device will simply fail. And there are many similar nuances when using a multifunctional digital voltage indicator.
Two-pin network testing devices
Such devices are already considered professional, although their domestic use is also quite common. On one of the probes, interconnected by a wire, there is a light bulb or a liquid crystal display. Such a voltage indicator requires the mandatory presence of a phase and zero (in a 220 V network) or two live 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 opposite phases. If the neutral conductor burned out in the junction box of the apartment and voltage was applied to it, the two-pole indicator will not show the presence of current.
As such a device, many use a test lamp, the wires from the cartridge of which are used as probes. However, this verification method is not secure. A conventional lighting device is designed for a voltage of 220-240 V. If zero breaks and is closed 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 is fraught with injury. In addition, in such schemes there are no restrictiveresistors, which can lead to electric shock if one probe comes into contact with a current-carrying contact, and the second probe touches an unprotected part of the human body.
The two-pole voltage indicator is quite convenient when it is 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 ground 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: nuances of use
Such devices are called high voltage indicators (UVN). They are used in the maintenance and repair of electrical installations with a rating of 400 V to 10 kV. Outwardly, such a current and voltage indicator looks like a long rod with a handle equipped with a restrictive ring to prevent the hand from slipping towards live parts. The device consists of:
- The contact element that comes into contact with the tire.
- A discharge or LED lamp that indicates the presence of voltage.
- A special window through which you can see the glow.
- Insulated rod between the handle and the contact part. Its length can be fixed or adjustable.
Interesting information! Not a single duty officer will sign a permit for servicing a transformer substation if there is no high-voltage indicator and protective equipment for working with it (rubber gloves, dielectric boots,mat).
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 indicators on different phases of several transformers, you can analyze the received information later, in a calm environment, and understand what actions need to be taken.
Voltage control devices of the car's on-board network
For such purposes, devices are produced that can operate at 12 V or 24 V. On-board voltage indicators always have 2 probes - otherwise it will not work to check the car's network. Notification for such devices may be different - LEDs, incandescent lamps or 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 lamps as an indicator of vehicle voltage is allowed. Sharp jumps are excluded here, which eliminates the danger of an explosion of a glass bulb. However, protection is still needed. A light bulb broken on metal parts can injure a person.
Making a voltage indicator with your own hands
It's quite easy to make a simple phase tester yourself. For this you will need:
- base fromburnt bulb (E14 or E27);
- cut cable channel;
- 0.47-1mΩ resistor;
- LED or neon bulb;
- regular nail length 50-70mm;
- soldering iron, electrical tape, wire, hot melt adhesive.
The algorithm for the production of works is as follows. Details are arranged in series - a nail, a resistor, a lamp. They are soldering among themselves. The contact platform dismantled 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 with pieces of wire. Mounting like this will increase the freedom of action when placed in the case.
Next, having opened the cover of the cable channel, inside the assembled circuit is carefully laid in such a way that on one side, on the end, there is a contact pad, and on the second, a nail sticks out. After placement, the parts are fixed with hot glue. 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 no more than 1.5 cm bare. Thus, without wasting time and money, you can independently assemble the voltage indicator.
Control lamp for checking the on-board network of the car
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 needed to make it. Flexible copper conductors are soldered to the contacts of the base, after which they are insulated. It also does not hurt to cover the contact ends with a layer of tin or use small probes instead of probes.nails. The check is performed as follows. One of the probes is connected to the frame, car body or negative battery terminal. Care should be taken to ensure that there is good contact, which can be interfered with by a layer of paint. The second probe checks the contacts. When in contact with a point that carries a positive charge, the lamp will glow.
It is also easy to make a device for monitoring the integrity of the electrical circuit, popularly referred to as "arkashka". To do this, it would be rational to use an LED from a lighter. If sound notification is required, a good device can be made from a children's toy. To do this, the contact switch button is disassembled, instead of which 2 wires with probes are connected. In this case, when the buzzer or LED is shorted, battery voltage will be supplied. Such probes can be used to test the windings of electric motors, coils of heating elements or various microcircuits.
Is it rational to independently manufacture such devices
Based on the cost, it is 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 production of such devices is strictly prohibited. Calculate the degree of protection here will not work. At the same time, if it is insufficient, an electric arc may form between the transformer bus andbarbell. Even with the presence of protective equipment, such a discharge can cause many problems. Considering that its brightness and temperature are much higher than the welding arc, it is easy to imagine what kind of eye burns can be received.
Final part
To be able to use voltage indicators is required for every home master, regardless of his education. These are quite useful devices that make it easier to troubleshoot problems in the home electrical network. Which type of device to choose is up to everyone to decide for themselves. The main thing is to follow the safety rules when using it.
