Generator circuits for testing multi-core wires. Cable and wire testing - methods, diagrams, testers

Many have encountered this situation when there is no voltage in the outlet. The reason for this in most cases may be a broken wire. In this case, you need to ring the cable that powers this outlet. Continuity testing is a test of electrical conductors for integrity, breaks and the absence of short circuits between them. This action will help determine where the breakdown occurred in the electrical network. Next, we will tell you what devices can be used to test wires and cables.

Dialing methods

There are several ways to ring wires at home:

Using a light bulb and battery. This is the simplest and quick method. In order to construct such a device, you need to have a light bulb and a battery (several batteries can be connected together), as well as connecting conductors and a probe. In addition, do not forget that the voltage of the light bulb and the battery should be the same, or the battery should have more, but not vice versa. The connecting wire must be long enough to ring the wire from a distance.

In order for the dialer to work correctly, it is necessary to mark the cable in any order. The operating method of such a device is as follows: a wire that comes from the battery is connected to one core, and a light bulb is attached to the probe. Use this probe to touch the conductors at the opposite end of the cable one by one. If the light comes on, it means this wire is connected to the battery.

You can learn how to ring the wires of a light bulb and a battery from this video lesson:

Using a multimeter. This device measures various parameters of the electrical network (for example, voltage, current, resistance). In the house, such a device will be indispensable if you need to check an outlet or switch, check for a break, or find out where the wire goes.

You can test the cable with a multimeter using the following method:

1. The dialing function is installed. Depending on which model of device is used, this mode is designated differently. As a rule, it is indicated by a diode.
2. Then you need to find the phase in the distribution box. This is done as follows: you need to turn on the power and use an indicator screwdriver to check each cable. We mark the one we need with tape or tape and then determine zero.
3. After this, you should find the voltage. To do this, set the multimeter to the “voltage measurement” mode. Using a probe, we check each wire. If the next time you touch the probe, it lights up around 220 V, then the right one has been found.

To check the electrical wiring in the wall for integrity, you need to disconnect the cable from the power source. Set the multimeter to resistance measurement mode. When the probes are closed, zeros should appear on the screen.

The video below clearly demonstrates the technology of testing a cable with a multimeter:

These two methods are convenient if the dialing is carried out over a short distance and can be done by one person. If the cable is long and its ends are located in different rooms in the apartment or outside, then use a different method.

Using handsets. Dialing with telephone headsets is carried out as follows: the capsules in the handset are connected to each other and a battery is connected to them, the voltage of which does not exceed two volts. Thanks to this technique, workers can talk to each other over the phone and coordinate their actions.

Cable wiring diagram using telephone handsets:

You can ring as follows: the cable on one side is connected to the tube conductor, and the other conductor is connected to any core. On the other hand, the cable connects to the tube conductor, and the other to each core in turn. If workers can hear each other on the handset, it means they are connected to the same conductor.

You can see the entire technology of work in this video example:

Using a transformer. There is another way you can call cable lines- this is a continuity test using a transformer, which has several taps coming from the secondary winding. The technique is as follows: the beginning of the winding is connected to the grounded shell of the conductor, and the transformer taps are connected to the cores and power each of them. If you measure the voltage that exists between the shell at the other end and the conductors, you can determine whether the end belongs to a specific conductor. The dialer will allow you to identify and mark the necessary cores. You can find out about this from our article.

Cable phasing

Phasing is the ability to determine in what order the phases alternate when parallel connection. This is necessary in order to avoid. Indeed, in order to increase the reliability of power supply, sometimes one conductor is not enough (or if the consumer’s power is too high). In order for the electrical installation to work normally, another wire is placed in parallel. In this case, it is necessary to take into account the phase rotation. The phasing diagram is shown below:

Phasing can be done in several ways: using a voltmeter or an incandescent lamp. A voltmeter is used for 380/220 V installations. The technique is as follows: cable 2 in the first installation is connected using a switch, and in the second, thanks to a voltmeter, it determines the voltage between the core and the bus to which it is planned to be connected.

If the voltage is linear, then the core and bus have unequal phases, so connecting them is prohibited. If the voltmeter displays zero, then this indicates that the wire and the bus have the same potential, respectively, they have the same phase and can be connected. Other conductors are tested using the same method.

If there is no voltmeter, then phasing can be done using two incandescent lamps that are connected in series and have a rated voltage of 220 volts. If the lamps do not light, then the wire and bus belong to the same phase.

You should also take into account the fact that after such actions a certain voltage remains on the cable cores, which is associated with a residual capacitive charge. Therefore, the cable should be discharged after the next passage of voltage. This is done by connecting the conductors to grounding.

So we looked at the main methods of testing wires and cables, as well as devices that can be used for such work. We hope the information provided was useful and interesting for you!

Situations when electricity stops flowing to devices arise quite often and are familiar to any electrician firsthand. There can be a lot of reasons for this, but in most cases the so-called break in the line is to blame. Such a malfunction can only be determined by checking the wire. In this article, together with the site, we will answer the question of how to ring the wires and determine which of the many has suffered damage? In addition, we will talk about how professional electricians determine the location of damage to hidden electrical wiring.

Wire testing device photo

How to ring wires: methods and devices used

Testing wires at home can be done in two ways: using a multimeter and using improvised means such as an ordinary light bulb with a socket. The last option is somewhat inconvenient, but the first is quite simple and accessible for independent implementation. We will consider both options, since sometimes it happens that there is no device at hand, but the result is needed immediately.

Let's start with the first method, which involves using a multimeter. To make it clearer, let’s look at a simple example and use a wire tester to check the integrity of the wire for connection system unit computer to . As a rule, it contains three cores - we will work with them.

How to connect wires photo

We take out a multimeter, turn it on in resistance measurement mode (ohmmeter), close the contact probes and set the indicator arrow to zero. Now let's start testing the cable. We attach one probe to one of the contacts of the plug, and insert the second one in turn into the holes of the connector to connect the cable to the system unit. We observe the indicators of the device, or rather its needle - if the ohmmeter shows the wire resistance within 2-3 Ohms, then the wire is in good working order, but if it exceeds 10 Ohms, this is a clear sign that there is a break on this wire. It may happen that the multimeter needle does not react at all to your actions - this only means that the contact on the plug and on the connector do not belong to the same core.

How to test wires with a tester

This is the way to test the wires with a multimeter. I would like to note that this testing method is suitable for wires for any purpose - telephone, computer, electrical.

It is not recommended to use the so-called “beeper”, which is equipped with almost all modern multimeters, to determine the integrity of the wire. It operates in the range from zero to several hundred ohms, and it will not be possible to determine the faulty wire with its help.

In almost exactly the same way, you can carry out dialing using a tester equipped with a voltage indicator. It should be understood that no voltage is supplied through a broken wire, and in order to ring the wires with a tester, it is enough to measure the voltage on its wires. On the indicator it should be displayed with identical digital values ​​that have different sign(“+” or “-”). The only drawback of this testing method is that the tester is able to determine the parameters of the wire only when it is energized.

Wire continuity photo

Another testing method is suitable for testing exclusively electrical wiring cables - it involves using a piece of ordinary wire with a light bulb. If we are talking about continuity of the lighting circuit, then you can get by with a long piece of single-core wire. The essence of this method is as follows. In the distribution box, the wires leading to one or another consumer of electrical energy are one by one discarded from the general power circuit and instead of them, a separate wire is connected directly to the consumer, the operability of which is beyond doubt. If everything works, then it can be considered faulty. If not, then restore it to its place and repeat the operation with another wire. electrical circuit.

In principle, by changing the starting point of connecting the additional wire and using a lamp as an indicator, you can ring almost any section of the apartment wiring. The method is excellent, and most importantly effective - its only drawback is some inconvenience associated with constant switching of wires.

How to test wires with a multimeter photo

Methods for detecting breaks in electrical wiring

We have sorted out the question of how to test the wires with a multimeter; the only question left is how to determine the location of the break? If this question does not concern hidden wiring, as for connection cords, there are few options here - the wire probably broke near the plug or plug. But what to do if we are talking about a break in a cable hidden in the wall? How then?

For these purposes, modern industry has developed a lot of devices of the “E-121” type - among professional electricians such a device is called a “woodpecker”. With its help, you can not only determine the location of the electrical wire, but also, if necessary, find the location of its break. Working with it is quite simple - guide it along the cable laid in the wall and watch the special signaling device. At the location of the gust, special electromagnetic anomalies are formed, to which the device reacts by sounding a sound signal.

Testing wires with a multimeter photo

There are also so-called old-fashioned methods of detecting hidden and faulty electrical wiring, tested over the years and by more than one generation of radio amateurs. To do this, you will need an ordinary radio receiver tuned to a wave frequency of 100 kHz. When moving it along the electrical wiring, you need to listen extraneous noise– where, in addition to increasing hissing, intense crackling will be heard, there is a wire break.

Now you know how to ring wires, and without the help of a specialist you can easily determine the reason for the lack of electricity in a particular place in the wiring, and, if necessary, locate the location of the break.

When carrying out electrical installation work, it may be necessary to test the cable, for example, when marking cores and wires, checking the insulation and integrity of the wiring, as well as searching for a broken electrical cable. Let's consider the ways in which testing can be carried out, as well as the equipment necessary for this purpose.

Methods

Testing methods depend on the purpose for which it is performed. To check the integrity of the cable for a break or electrical connection between its wires (short circuit), the test can be done with a tester based on a battery and a light bulb, or you can use a multimeter for this purpose. The latter is preferable.

Despite the fact that the price of a multimeter is higher than a primitive device, we recommend buying it; this device will always be useful in the household.

To check the cable, the multimeter must be turned on in the appropriate mode (diode or buzzer image).

The testing methodology is as follows:

When checking a wire for a break, the tester is connected to its ends as shown in the figure. If the cable is intact, the light will glow (when testing with a multimeter, a characteristic sound signal will be heard).

Explanations for the picture:

• A – electrical cable;
• B – cable cores;
• C – power source (battery);
• D – light bulb.

If the cable has already been laid, then on one side it is necessary to connect the wires together and ring the wires at the other end;

when checking the presence of electrical connection between the cable cores, the tester probes are connected to different wires. Unlike the previous example, there is no need to twist the wires on the other side. If there is no short circuit between the wires, the light will not light (when testing with a multimeter, no beep will sound).

Testing multi-core cables for the purpose of marking them

When marking multi-core cables, you can use the methods described above, but there are ways to significantly simplify this process.

Method 1: the use of special transformers that have several secondary winding taps. The connection diagram for such a device is shown in the figure.

As can be seen from the figure, the primary winding of such a transformer is connected to the power supply network, one end of the secondary winding is connected to the protective shield of the cable, and the remaining terminals are connected to its conductors. To mark the wires, it is necessary to measure the voltage between the screen and each wire.

Method 2: Using a block of resistors with different values ​​connected to the cable wires on one side, as shown in the figure.

To identify the cable, it is enough to measure the resistance between it and the screen. If you want to make such a device with your own hands, then you should select resistors in increments of at least 1 kOhm to reduce the influence of wire resistance. Also, do not forget that the value of the resistors has a certain error, so first measure them with an ohmmeter.

When checking a multi-core telephone cable, installers often use a dialing headset, for example TMG 1. Actually, these are two telephone handsets, one of which is connected to a 4.5 V battery. Such a simple device allows you not only to check the cable, but also to coordinate your actions during installation and testing.

Insulation check

To test insulation with a megohmmeter or multimeter, the principle of continuity is the same as when searching for an electrical connection between cable cores.

The testing algorithm is as follows:

• set the maximum range on the device - 2000 kOhm;
• connect the probes to the wires and see what the device display shows. Considering that the wires have a certain capacitance until it is charged, the readings may vary. After a few seconds, the device display can display the following values:
• one, this indicates that the insulation between the wires is normal;
• zero – there is a short circuit between the cores;
• some average readings, this can be caused either by a “leak” in the insulation or by electromagnetic interference. To determine the cause, switch the device to the maximum range of 200 kOhm. If the insulation is faulty, the display will display stable readings; if they change, then we can confidently talk about electromagnetic interference.

Attention! Before checking the insulation of the electrical wiring, it must be de-energized. Second important point– when taking measurements, do not touch the probes with your hands, this can introduce errors.

Video: Wire continuity check - integrity check.

Finding the break point

After a break in the electrical wiring has been discovered, it is necessary to localize the place where it happened. For dialing in this case, you can use a tone generator, for example, Cable Tracker MS6812R or TGP 42. Such devices allow you to determine the location of the break with centimeter accuracy, as well as determine the route of hidden wiring; in addition, the devices have other useful functions.

Devices of this type include generator sound signal and a sensor attached to the earphone or speaker. When the sensor approaches the place where the UTP cable pairs or electrical wiring wires are broken, the tone of the sound signal changes. When a tone test is performed, before connecting sound generator it is necessary to de-energize the wiring otherwise the device will fail.

Note that with the help of this device you can dial both power and low current cables, for example, check the integrity of twisted pair cables, radio wiring or communication lines. Unfortunately, such devices will not allow you to determine the correct connection; special equipment is used for this purpose - cable testers.

Cable testers

This class of devices allows you to check both the integrity of the cable and the correctness of its connection, which is very important for Internet provider networks. These can be simple devices that check crossover or complex devices on a PIC controller that have an ADC and a built-in multiplexer.

Naturally, the cost of such devices does not encourage their household use.

Homemade contactless dialing

Below is a diagram of a simple non-contact break detector; it can be assembled within one evening. Considering the small number of parts, you don’t have to bother making a printed circuit board, but use wall mounting.

List of required radio components:

• variable resistance R1 – 100 kOhm;
• resistor R2 – from 4 to 8 MOhm;
• electrolytic type capacitors: C1 and C3 – 220 µF, C2 – 33 µF;
• ceramic capacitor with a capacity of 0.1 μF;
• D1 – LAG 665 chip (preferably in a DIP package);
• SP – regular earphone from a telephone headset.

The circuit can be powered from a source with a voltage of 2 to 5 volts.

The feeler gauge (P) is made on the basis of a regular spoke from a bicycle wheel.

Correctly assembled contactless cable testing does not require adjustment.

Video: Do-it-yourself cable testing. How to test wires using a light bulb and battery

The most simple work Electrical related tasks are difficult to perform without measuring tools.
It is not at all necessary to measure the parameters of an electrical circuit with a tester; in many cases it is more convenient to use a universal probe that indicates the presence of these parameters through light signals. This is quite enough for convenient and safe work with electrical circuits.
The probe-indicator circuit under consideration does not contain batteries. Instead of the energy typically used in battery probes, it uses the energy of a charged capacitor.

Functionality.
The probe allows you to monitor the presence of alternating and direct voltage in the range from 24 to 220 V, carry out continuity testing of an electrical circuit with a resistance of up to 60 kOhm and determine the polarity in circuits DC.
When the XP1 and XP2 probes are connected to a direct current source in accordance with the input polarity, the green LED HL1 lights up, indicating not only the presence of direct voltage in the controlled circuit, but also the presence of a plus at the point of contact of the XP1 probe.
Changing the polarity on the probes to the opposite causes the red LED HL2 to light up, which, in addition to the presence of voltage, indicates contact with the plus of the HP2 probe.
When monitoring AC voltage, both LEDs light up simultaneously.
The continuity of the circuit during testing is indicated by the lighting of the red LED HL2.
This is the kind of information you can get with just two LEDs built into this simple indicator probe.

Probe design.

Radio components. To sell the device, you must purchase or find in your supplies the following parts:
Resistors R1-220 kOhm and R2-20 kOhm, power 2W, R3-6.8 kOhm;
LEDs HL1 – AL 307G, HL2 – AL 307B;
Diodes KD2 – VD5 – KD103 (possible replacement for KD 102);
Zener diode VD1 – KS222ZH (possible replacement for KS220ZH, KS522A);
Capacitor C1 - K50-6 1000x25.

Frame. Particular attention should be paid to the choice of housing - the convenience of working with the probe depends on its configuration and dimensions. Let's consider two housing options. The first option uses a relay cover, the second uses the body of an unknown gadget.

Holes are made in the housings for the output of the wire with the XP2 probe, LEDs are installed (only for the first option) and the XP1 probes are attached.
Pay. The dimensions of the case determine the geometry of the board. Installation can be hinged, but it is not difficult to do it on printed circuit board. All radio components (except for LEDs in the first version) are mounted on a board, which is mounted inside the case.

After installing the board into the case and soldering the conductors to the XP1 and XP2 probes, the probes and indicators are ready for use. The device does not need to be set up.
The charging time of the probe capacitor at a network voltage within 220-24V is 3-25 seconds. The capacitor discharge time when the probe probes are short-circuited is at least 2 minutes.