Quite often, even in domestic conditions, it becomes necessary to measure direct or alternating current without damaging the integrity of the electrical circuit. For this purpose, special clamp meters and a device with similar design features for alternating current were invented.
Application of electrical measuring clamp
AC and DC clamp meters are designed to measure current without breaking the circuit. None of the analogues provide such functionality. For example, to measure parameters with a multimeter, it is imperative to break the wire, which is not very convenient and safe.
You can connect a current clamp for measuring DC and AC current to any wire, it does not matter whether its surface is insulated or not. During operation, the pliers are required to be applied to the wire or to just one bus. The value of the measured parameter should be displayed on the panel.
Most modern models are equipped with a special locking button that allows you to take readings in hard-to-reach places.
Clamps for measuring current strength have a fairly large list of functions. Used in the following cases:
- Calculation of the amount of electricity consumed by a specific electrical appliance.
- Determination of equipment power.
- Calculation of the actual network load.
The devices are actively used in various industrial enterprises, power plants, factories, as well as in other industries. In everyday life, they are also often used to determine the power of home appliances.
Clamp meter measurement methods
There are only two ways to measure the parameters of the electric current in the circuit. The first is indirect or inductive current measurement, and the second is referred to as direct measurement.
Inductive way
In this case, DC and AC current clamps operate on the principle of a current transformer. The primary winding is the measured conductor, the secondary is the clamp itself.
Advantages of the indirect method:
- safety;
- in comparison with the direct method, the ability to measure large currents;
- the ability to take measurements without breaking the circuit;
- simplicity and portability of the procedure.
Among the disadvantages of inductive measurement, it is worth highlighting the large error and the inability to determine the parameters in hard-to-reach places.
Direct way
Direct measurement is carried out using an ordinary ammeter, it is connected at the point where the electrical circuit is broken. The essence of the method lies in the passage of current directly through the ammeter. As a result, the obtained value of the measured parameter is displayed on the control panel.
The advantages of this method include:
- simplicity, ease and convenience of computing;
- measurement accuracy, which depends on the quality and accuracy class of the device.
The disadvantages include the inability to measure large currents due to technical characteristics. It is also impossible to carry out calculations without breaking the circuit.
Measurements in electrical installations with voltages above 1000 V have no specific features. Clamp meters allow you to quickly, with high accuracy, without much effort, calculate the parameters of the current in the circuit.
To take measurements, you need to perform the following manipulations:
- The measured value is set using a special switch.
- Pincers are bred to the side and put on the conductor.
- The handle is lowered and the device is closed.
The equipment counts the data, after which it can be turned off.
Advantages and disadvantages
The great demand for the tool is due to the advantages:
- Possibility to save values in the device's internal memory.
- The small size of the devices allows them to be used even in hard-to-reach places.
- The non-contact method of measurements allows you to increase the permissible limits up to 10,000 V, which is not possible when the ammeter is connected in series in the circuit.
- Easy and safe measurements even in electrical circuits where voltages can reach 10,000 V.
- Clamp meter measurements can be made without breaking the circuit for daisy-chaining equipment.
Experts point out the following disadvantages:
- Low measurement accuracy: the maximum class is only 2.5.
- The wire must have an exact location relative to the plane of the frame, sometimes, in cramped conditions, it is not possible to fulfill this condition.
Universal equipment that combines the functions of a clamp meter and a multimeter is gaining rapid popularity. The price of such devices fluctuates over a fairly wide range.
What to consider when choosing
In order for the selected device to be able to fulfill all the tasks assigned to it, it is necessary to select the correct modification with optimal technical characteristics. When making a purchase, you should adhere to the following rules:
- The equipment should be purchased in specialized stores or from official representatives of manufacturers of current measuring equipment. If there is not enough experience for an independent choice, you can get advice from specialists.
- Before purchasing, it is important to test run the clamp to ensure that the measurements are as accurate as possible.
- When choosing, you should also pay attention to the type of measured current. Equipment designed to measure AC / DC current is marked AC / DC, respectively.
- For use in everyday life, it is recommended to give preference to models that additionally calculate the circuit resistance, voltage and its "continuity".
- Before purchasing, you need to decide what quantities you will have to deal with in measurements. Each device has a maximum and minimum allowable values.
- It is worth refraining from buying an expensive device with a large number of additional functions, if it is needed solely for calculating the current strength.
- It is necessary to analyze the diameters of the tires and wires with which you have to work. Based on these data, the size of the ticks is determined.
- Sensor type. There are different types of clamps, each of which can measure current in different quantities, for example, mA, A and AC. This should also be considered when buying.
- The material from which the body is made. To protect a person from possible electric shock, only high-quality materials should be used for manufacturing. It is worth refraining from purchasing models of dubious quality, with an unpleasant smell. If there are gaps in the body, the parts are movable - the assembly leaves much to be desired.
Having chosen a certain model, it is important to carefully read its technical characteristics, as well as to make sure that the accompanying documentation and a warranty card are available.
