Case studies(Introduction examples)

Lightning protection for factories

No. 1 impact of lightning damage. Factories are among the facilities with the highest lightning risk.

Modern factories are built with all equipment controlled and extensively networked. The factory is wired in a variety of ways. For example, remote monitoring is done between the factory and the head office using serial communication such as RS485 to monitor production equipment. Even within the factory premises, wiring for pump control, communication, ITV cameras, etc. are connected between the factory and different buildings. When there are production facilities in multiple buildings, there are various types of wiring running between the buildings. In many cases, the wiring is several dozen meters to several hundred meters long, making it easy for a potential difference to occur between the grounds (making it easy to be affected by lightning surges).
In addition, factories are often located in the suburbs near mountainous areas, and because mountainous areas are prone to updrafts, thunderclouds are easily generated, making them even more susceptible to the effects of lightning.

Dangers if no measures are taken
  • Production facilities damaged by lightning surge; production records and other data lost
  • Temporary suspension of operations and delays in shipments, etc., from the time of damage until recovery work

Lightning protection points for factories

Countermeasure points
The rooftop and bottom floor of the factory, the electric power intake area, and the telephone line intake area are affected by direct lightning surges (LPZ1), so SPDs (Class I, Category D1) are installed for direct lightning surges. The middle floor is affected by induced lightning surge (LPZ2), so SPD (Class II, Category C2) should be installed to cope with induced lightning surge. It is effective to install SPD for power supply on each floor or each distribution board.

As a characteristic of factories, damage due to potential differences caused by wiring between multiple buildings is expected. For this reason, SPDs should be installed at each wiring entrance to control the potential difference. It is important that the SPDs at each wiring entrance are grounded for each device, and that the SPDs are not connected to each other. If the SPDs are connected, the grounding of each piece of equipment will be connected to each other, and there is a risk of generating a potential difference between the groundings.
For important equipment such as pumps and central monitoring panels, implement measures for each individual piece of equipment. When there are multiple grounding poles, a potential difference occurs between these poles and lightning surges can enter, so Class I SPDs are connected between each grounding to suppress the potential difference.

A lightning receiving unit should be installed as required. When installing a lightning receiver, it is necessary to install a SPD (Class I, Category D1) that is capable of handling direct lightning surges, since the inflow of current from direct lightning strikes is also expected. In addition, using grounding resistance reduction material and lowering the grounding resistance value is very effective because it can smoothly neutralize lightning surges even if lightning strikes the receiving area.
We also offer SPDs for equipment that can be mounted directly inside the equipment. By attaching it to the main body of a machine tool, etc., the equipment can be more reliably protected from lightning surges.

Installation example

Lightning protection products for factories