Surge Arrester Installation

The most important point, as much as the selection, technology and product quality of the LV surge arrester, is the installation and application of the LV surge arrester. If the product is installed incorrectly, it will not operate properly and will not protect your system. Unfortunately, based on our observations as Yılkomer, it is seen that LV surge arrester systems are installed incorrectly. The most common mistakes include excessively long surge arrester connection cables inside panels, routing the surge arrester cable throughout the entire panel, and connecting the surge arrester at the top of the panel and then reaching the lower busbars with very long conductors. The most important characteristic for surge arresters to provide protection is the Up value. If the Up value is high, the surge arrester cannot provide proper protection; a value below 1.5 kV is considered medium level, and below 1 kV is considered very good. However, since long conductors have inherent voltage, it is impossible for the Up value to reach these levels when the surge arrester is installed with long cables. In fact, with today’s technology, wireless-connected surge arresters such as Strikesorb stand out as products with the highest level of protection.

Panel-type Type 1 Class B and Type 2 Class C surge arresters must be connected in parallel to the system. For Class B, a minimum conductor cross-section of 16 mm2 must be used, and for Class C, a minimum of 6 mm2 must be used. Keeping cable lengths under 50 cm is the most ideal connection for us. Installation should be carried out at points close to the grounding busbar; products connected in parallel to the system do not have to be mounted at the top of the panel. Lightning generally reaches the facility through the ground, and placing the product close to this busbar is the most correct installation method. Type 3 Class D surge arresters are connected with 1.5 mm2 cables and can be connected either in series or in parallel to the system.

A protective fuse can be used in front of the products in line with the product technology. The NH-type fuse rating to be selected is provided to the user by the manufacturer. However, generally, 125 A fuses can be used for Class B and 63 A fuses for Class C. In addition, connection cables should be kept as short as possible. However, the use of fuses is not always correct; especially in remote facilities, unnecessary fuse tripping may leave the system unprotected. In such cases, RAYCAP Safetec technology products are suitable for fuse-free use. Although they have internal protection circuits, they do not require the use of fuses.

So how should surge arrester grounding be in the installation of surge arrester systems? Before this, we must 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 differently according to these grounding types. In product selection, we must primarily choose the correct product for the correct grounding structure. In terms of product technology, it is definitely more appropriate to select products that perform bidirectional chemical damping rather than products that rely solely on varistor endurance. Because these products provide damping independent of the grounding value. However, we should never give up the fast activation characteristic of varistors. For this reason, we recommend Raycap surge arrester systems with 3-circuit Safetec technology.

When we examine the standards, a clear value is not specified for surge arrester grounding resistance. In fact, such a strict resistance value is not required. What is important is connecting the surge arrester to the grounding line from the shortest possible point. Manufacturers who trust their products should never use grounding values as an excuse. For example, for Raycap Strikesorb technology products, it is sufficient that they are only connected to ground.

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

You can always receive support from the expert team of the Lightning Protection Center for the selection, installation, reporting and technical inspection of surge arrester systems.

Remember that in the use of surge arresters, application and product selection are the most important points.