PAT for electrical equipment safety

The global trend of electrification means that there are more and more devices around us powered by electricity: from computers, televisions or coffee machines, through construction equipment such as power tools, or welders to industrial equipment such as presses and lathes. We use them every day and often reflexively, but are they safe? Defective devices are a common cause of fire, accident, loss of health and even death.

How to test such devices? Norms and legal acts relating to periodic testing of electrical equipment come in handy. In many countries where device testing is mandatory, norms are often cited in legal acts and are obligatory to use, e.g. the German standard VDE- 701/702. However, if there are no clearly defined regulations that should be used, you can refer to harmonized standards or norms of other countries - German, British, etc.

The group of standards for the safety of electrical equipment also includes a norm that clarifies the rules for checking welding equipment. This is the EN 60974. The conditions in which welders usually work can be considered heavy - not only for man, but also for the equipment used

What to do? The measuring instrument should enable assessment of the device's efficiency in accordance with applicable standards, allow to save and store data and have appropriate documents confirming its efficiency (EU declaration of conformity, calibration certificate). PAT-86 was created for testing electrical devices and welding machines. It not only meets the above requirements, but also Sonel's high standards of product design.

One of the first things to do during check-ups is the visual test. PAT-86 has the ability to program a visual test according to your preferences. During the measurement, the meter will force you to inspect individual elements and confirm this action by checking the appropriate boxes on the screen. The elements for verification can be pre-programmed by the PAT Analysis software when creating the measurement procedure. By default, the test contains the overall result of the examination.

For devices in the first protection class, the continuity and resistance of the protective conductor should be measured. The purpose of this test is to check that the available metal components are connected to earth. The PAT-86 meter gives the possibility to check the protective conductor connections with a 200 mA current. In addition, thanks to the use of an efficient current generator, it can be measured with a 10 A or 25 A current, which results in an accuracy of 1 mΩ.

Two measuring methods are available: two- and four-wire. In the case of the two-wire method, there is the possibility of auto-zeroing, i.e. correction of the result by the resistance of the used test leads. and for the four-wire method, the resistance of the test leads is compensated and does not affect the final result.

The next step is to measure the insulation resistance. Good insulation is the basis for effective protection against electric shock. PAT-86 provides measurements with voltages of 100 V, 250 V, 500 V and 1000 V DC at a current of up to 1 mA! In connection with a large measuring range (even up to 599.9 MΩ), it gives the possibility of an accurate control of the insulation condition.

Standards - whether international, German or British - often require checking leakage currents. These are the currents flowing to the ground:

- through the device insulation,

- through capacities present in the device,

- as a result of unwanted conditions such as short circuits or insulation damage.

A distinction is made between substitute, differential, touch and PE leakage current. PAT-86 measures each of the abovementioned currents.

During the measurement of the substitute leakage current, the meter gives a reduced safe voltage and converts the result to the current that would occur during operation with the nominal voltage. When measuring the differential, touch and PE leakage current, it is possible to change the polarity. In addition, the measurement of the differential and PE leakage current can be made using clamps, which facilitates tests of devices permanently connected to the power supply network.

Often one of the tests of an electrical device is the idle test. PAT-86 gives you the option of performing a functional test. The meter checks the current consumption, active, reactive and apparent power of the device, cosϕ, power factor (PF), current and voltage THD. The measurement can be done with current clamp and voltage leads or via a schuko socket.

With the optional accessories, the meter allows testing of extension cords and IEC cables. During these measurements, PAT monitors the protective conductor resistance, insulation resistance and carries out a polarity test. Increasingly, you can find extension cords or devices protected by RCDs (PRCDs). These switches can be checked easily with a new PAT, regardless of whether it is a general purpose switch or a 10 mA, 15 mA or 30 mA short-time delay switch. You can choose the shape of the current waveform, as well as measure the response time at rated current multiplications (0.5 I∆, 1 I∆, 2 I∆, 5 I∆). In addition to portable circuit breakers, the meter can check stationary residual current devices in the switchgear.

The measurement of welding equipment is a very important advantage of PAT-86. For welders, in addition to the visual test, continuity of the protective conductor, insulation resistance and leakage current in the PE conductor, you must also perform:

- primary to secondary resistance measurement (welding circuit),

- PE to secondary resistance measurement,

- welding circuit leakage current and no-load welding circuit voltage.

All this can be done with the new PAT-86 meter!

The PAT-86 has a clear 5.6 '' LCD touch screen and an automated autoprocedure system, fully programmable by the user. Thanks to the ability to set limits and the duration of the measurement, the meter can perform the measurement sequence itself and evaluate their results. Data transmission via USB, Wi-Fi or LAN is possible - along with the optional PAT Server application, the meter can operate in the cloud system, which allows remote, smooth operation and data management.

A clear and simple memory structure in a tree-like form enables the creation of clients, objects and devices, which in combination with a QR code system (the meter works with a printer and a code scanner) significantly facilitates work and recording. The meter also has a "multibox" function, this function allows multi-point measurements, it is useful when the device has more than one measuring point, e.g. PE continuity measurement of multi-socket extension cords. The whole is closed in a durable, compact housing.

 

Michał Cichoń

Junior Product Manager

SONEL S.A.