Several issues to consider when choosing a grounding resistance tester:
Does the test site have high soil resistivity and/or require longer test leads?
Whether the soil resistivity of the area to be tested is very high or whether the distance required for the auxiliary rod to perform the potential drop test is unusually long. If the answer to either or both of these questions is yes, and you intend to perform potential drop and/or soil resistivity tests, the instrument's injection current and test voltage must be considered. Typical injection currents range from a few milliamps to several hundred milliamps.
High soil resistivity usually produces high contact resistance to the auxiliary electrode. This may be of concern when using a low-cost grounding resistance tester that typically provides 10mA test current; Therefore, in this case, we recommend using a ground resistance tester that provides a higher test current. Before we leave the subject of auxiliary electrodes, please note that clip-on ground resistance testers do not require any auxiliary rods or leads. Another advantage is that you do not need to use a grounded system to perform tests.
Is there electromagnetic interference (EMI)?
Another consideration is whether there is electromagnetic interference or EMI at the test site. EMI can lead to erratic or inaccurate readings, especially at lower test frequencies. A common test frequency is 128Hz. Ground resistance testers with automatic test frequency selection can find "clean" available frequencies, which is advantageous in high EMI environments.
Clamp type grounding resistance testers can also be effective in these locations, as they are usually tested at higher frequencies. Newer AEMC clamp-on models also offer test frequency selection. Note that in some highly sensitive environments, lower test frequencies can produce more reliable results.
How are measurements used?
The choice of grounding resistance tester also depends on how you intend to use the data obtained. For example, if you plan to save, analyze, and distribute test results, data storage and report generation become important considerations. Newer, smarter grounding resistance testers, including 3-pole and 4-pole testers and clamp-on models, can store test results in internal memory. This data can then be downloaded and analyzed using software running on a computer or mobile apps for smartphones and tablets.
Do you need to test the connection of grounding system components?
If you plan to test a complex grounding system consisting of many components including floor MATS or grids, you will need to test the continuity of connections between the various components. This test is usually performed using DC voltage and current. Multiple grounding resistance testers provide this functionality, testing current up to several hundred milliamps. In addition, a microohmmeter can be used for more complete testing. The advantage of using the digital grounding resistance tester is the ability to test at high test currents up to 200A. This can reveal problem areas that do not always show up when tested using milliamperes.
Wuhan Xinshengneng Technology Co., Ltd. specializes in the production of grounding/insulation series of test equipment, the production of a variety of products, complete models, cost-effective products, welcome to call 0312-3188565 consultation!
