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Explore what is the leakage current and the application ...

Jul. 29, 2024

Explore what is the leakage current and the application ...

15 Mar,

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Author: Cherry Shen

Leakage current is the current flow going through a piece of insulating material when certain voltage is applied. It can be used to estimate insulation resistance in power systems, since almost none insulation material can be 100% nonconductive. The flow of leakage current indicates the losses of voltage in insulator, thus the determination of its insulation performance can be made.

The principle of measurement: After applying a direct current voltage to the test equipment, the microameter will record the gradual attenuation of the charging current in a certain period of time, and the final reading roughly reflects the leakage current. To ensure the reliability of the test results, repeatability measurement and control of the test environment conditions can be taken.

Leakage current tester is a very useful electrical testing tool, which helps users detect and find out electrical safety hazards, and ensure its safe operation. This tester is widely applied in lots of scenes such as home, industry and hospital, and it is quite easy to operate: make sure that the equipment is correctly grounded first, then plug the tester probe into the power socket and connect to the grounding point, finally, start up the tester and check the testing results. If leakage currents is found, further inspection of the electrical system should be made for timely repair and correction. Apart from testing leakage currents, the tester can be used for testing short circuit of line, grounding fault and other security hazards, regular use can improve safety of electrical appliance.

When Using Leakage Current Tester, Noted Points Should Be Kept In Mind:
1. In the electrical test, the leakage current value should be read in steps by increasing the voltage step by step. After each voltage increase, keep for 1 min, and wait for the microampere meter to be steady, then read the leakage current value and draw the characteristic curve;
2. Before the test, check the connection, the range of the instrument, and the zero position of the voltage regulator; After the test, first turn the regulator back to zero position, then disconnect the power supply and ground the tested product;
3. Record the on-site temperature, convert the leakage current to the standard current under the standard temperature (generally the calibration temperature is 25') for comparison. These are the important points to be aware of when conducting electrical safety tests.

As a type of electrical equipment insulating tester, leakage current tester has multiple significant advantages during use, including wide test range, high-precision testing, easy operation, safe and reliable and data recording and analysis. Firstly, leakage current tester can test various types, powers of electrical appliance, equipment and wires, including single-phase and three-phase current testing. Secondly, it has high-precision testing functions with small testing errors, ensuring accuracy of testing result. Moreover, it operates easily with 10.4 inch full-color touch screen, which helps users input testing parameters quickly, and the testing interface shows dynamic test process during the entire testing, so the test result is crystal-clear.

In addition, it is loaded with multiple safety protection functions to prevent current short-circuit or other accidents, which ensures safety and reliability of test. Finally, it can save test data locally and provide data analysis functions for quickly judging whether the test result meets requirements or not. Hence, it can be seen that the leakage current tester becomes increasingly important in electrical safety inspection.

Based on its convenience, easy operation, reliable testing, leakage current tester is widely used in multiple industries, for example, lighting industry, home appliance industry, power tools industry, new energy vehicle industry and electronic instrument industry. Lights such as desk lamp, street lamp and car lights can use leakage current tester to test their leakage current; home appliance like refrigerator, cold storage and air conditioner can use this tester to view their leakage current status; moreover, electrical equipment like drill, planer and saw, components and new energy vehicle, and electronic medical equipment, laboratory equipment, industrial automatic equipment can use the tester for testing and monitoring. The emergence of leakage current tester relieves users from complex test procedure and effectively carry out electrical safety test, providing them with more excellent operation service.

Leakage current tester tests the leakage current of electrical equipment in a fast and effective manner, determines if its safety performance meets requirements, and it is an important instrument in safety production management, as well as a reliable choice in leakage current detection of electrical equipment. The use of leakage current tester can significantly reduce the danger of electrical equipment leakage current, and solve the security problems of electrical equipment, protecting personnel and property security, as well as improving the safety level of production and society.

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The leakage current test

Do I feel safe?

Am I doing everything right?

You will know for sure in a few minutes.

Safety tests are mandatory and are part of every final inspection of your electrical product.
Learn the most important facts about the leakage current test.
We explain the WHY?, WHERE? and HOW?
And if you would like to learn more, you can download even more detailed information at the end of this page free of charge!

The INSULATION?

As is the case with the insulation resistance and high voltage test, the leakage current test is all about the quality and safety of the insulation.

The leakage current test takes place during the actual use of the electrical product. For this purpose, the electrical device is connected to the operating voltage and tested to see whether too high a leakage current flows through the insulation to the housing. It is therefore a combination of a safety and functional test.

WHY?

Safe insulation is the central protective measure to ensure electrical safety. It ensures that the user does not touch live conductors and that no short circuit can occur between the conductors or to the housing of the equipment. Because if it did occur, a life-threatening current could flow through the user if he or she touched the housing. Obviously, the protective earth conductor should ensure that this does not happen. But in the worst case it could also be defective. And it would also only be an evasion of the effect, not of the cause.

In order to guarantee all this, the insulation must work perfectly! And this must be proven and documented by you with a leakage current test before the electrical product is delivered.

This test is not mandatory for all electrical products. However, it may well be required for the certification of the electrical product in the type test. If it is required during manufacture, it is a routine test. This means that every piece, i.e. every single electrical product you put on the market, necessarily requires a leakage current test .

HOW?

Since the insulation has 'something to do with the voltage', the test is carried out with increased nominal voltage. The increase is typically + 6%, + 10% or + 15%. The reason: since the mains voltage could be increased by up to + 10% at the end customer's premises, this should be simulated accordingly during the test. The electrical product is thus in an operating state with overvoltage.
This type of procedure has the advantage that during the test, as many components of the electrical product as possible are temporarily or permanently live.
The test is often referred to as the 'warm leakage current test&;. Logically, there is also the 'cold leakage current test&;. Consequently, the electrical product is not operated in this test. The test intensity is lower here.

The aim is to measure the current through the insulation in a wide range of fault conditions. This is because it is the evaluation criterion for the insulation. It must never be greater than a specified maximum current during the entire test period.
The upper limit of the leakage current can be defined differently from product to product and in different regions/continents. Therefore, you must take the test parameters from the standard applicable to the product and region.

The current measurement is not only a simple current measurement with a multimeter!
No, the user is simulated by various RC networks (resistor-capacitor networks). These are defined in the standards for different, possible error cases.

The test is carried out under various fault conditions automatically simulated by the tester.
The leakage current in the protective earth conductor of the electrical device is measured.

If there are housing parts on the electrical product that are not connected to the protective earth conductor, the test is performed using a test probe.

For 25 years, complex tests have therefore always been carried out automatically at any test points via the SCHLEICH-typical matrix, which is fully programmable:

Test parameters

typical norm values

Are you interested in learning more about current leakage tester? Contact us today to secure an expert consultation!

SCHLEICH | from standard to customized

test voltage
1.05 ' 1.1 x Unominal
1.0 ' 1.15 x nominal voltage

max. permissible test current
1 ' 30 mA
1 µA ' 500 mA

minimum test duration
1 s
from 0.1 s to 24 h

measurement circuits EN
3
1. measurement circuits: unweighted touch current
2. measurement circuits: touch current evaluated for perception and reaction
3. measurement circuits: touch current evaluated for release

measurement circuits EN
1
1. measurement circuits: EN

measurement circuits UL
1
1. measurement circuits: UL + UL

measurement frequency
500 Hz, 1 MHz
up to 500 Hz / 1MHz

With this range of requirements, it is of course ideal to use a test device that covers as many of the world's standards as possible.
That is SCHLEICH's strength.

LEAKAGE CURRENT up to 1 MHz ?

More and more modern electrical products have integrated electronic components. Very often switching power supplies are used for internal power supply. These can produce pulse-like leakage currents with very high frequency parts of up to 1 MHz. In order to be able to test these, the leakage current measurement technology must also be dimensioned to 1 MHz.

The effort involved is not inconsiderable.
SCHLEICH offers the 1 MHz leakage current test including factory calibration or DAkkS calibration! The harmonic response of the measuring circuit is also documented.

All set? Want more details?

Our mission ' know-how, know-how, know-how' Those who understand the test methods with technical and normative certainty will get the most out of their test device.
' Dipl. Ing. Martin Lahrmann

Yes ' tell me more. I want maximum security for our customers, our company and myself.

Send me more detailed information from the SCHLEICH test method handbook.

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