Surge Arrester Grounding

Panel-type LV Surge Arrester Systems must be used in all main and sub panels of facilities within the scope of IEC 62305 Standards. In our article published last month on the blog, we explained surge arrester selection and installation in detail. So, how should surge arrester grounding be in the installation of surge arrester systems? Before addressing this issue, we need to focus on product selection. Your panel grounding structure varies according to the condition of the earth and neutral lines as TT, TN-C, or TN-S. Surge arresters should also be designed according to these grounding types. In product selection, we should primarily choose the correct product for the correct grounding structure. In terms of product technology, it is definitely more appropriate to choose products that perform bidirectional chemical damping rather than selecting only varistor-based products. Because these products provide damping independent of the grounding value. However, we should never give up the fast response characteristic of the varistor. For this reason, we recommend Raycap systems with 3-circuit VG technology.

When we examine the standards, no specific value is given for surge arrester grounding resistance. In fact, such a strict resistance value is not required. What is important is that the surge arrester is connected to the grounding line from the shortest possible point. The cable cross-section of this connection is of great importance depending on the product class. Class B products must be connected with 16 mm2 cables, and Class C products with 6 mm2 cables. The connection must be solid and free from arcing. Therefore, products manufactured by companies producing in accordance with IEC standards should be used.

If we do not want the lightning impulse to be directed to our facility through the grounding line or want to reduce its effect, an equipotential bonding must definitely be established within the facility with the external lightning protection system. However, this equipotential bonding connection must be made using damping surge arresters.

For surge arrester system selection, installation, reporting and technical inspection, you can always receive support from the expert team of the Lightning Protection Center.

Remember that application and product selection are the most important points in surge arrester usage.