Termination rods suitable for external lightning protection. It can be used as single sensor element or part of passive protection, complementing the protection conductive mesh (Faraday cages). Made of AISI 316L stainless steel or copper.


In order to design an effective lightning protection system with Franklin rods or capturing meshes, the following rules shall apply:

  • IEC 62305:2013 Lightning protection (Parts 1, 2, 3 y 4).
  • UNE - EN 62305:2011 Protection against lightning (Parts 1, 2, 3 y 4).
  • NFPA 780:2014 Standard for the installation of lightning protection systems.

In addition to these rules, legislation may exist in each country to be taken into account.


WAT Franklin Plus E.S.E Lighting conductors has an online tool that allows the risk calculation according to IEC 62305 (Part 2), which allows the calculation of risk and the implementation of protective measures quickly and easily.

Calculation methods of the protection zone

Accepted methods for determining the area of passive protection systems according to IEC 62305 (Part 3) are:

Protective angle method

It is best suited method for buildings with simple shapes, although it is limited to a maximum height to the level of protection applied (See graph).

The volume of protection resulting from the application of the protection angle method in a termination rod is shown in central image.

Once calculated, the different angles of protection of the termination rods that make up the system verifies that the building is fully protected.

Ángulos de protección correspondientes a las clases de los SPCR norma IEC 62305-3.
Volumen protegido por una punta franklin pararrayos
volumenes franklin en edificio

Rolling sphere method and the mesh method

When a structure has a height higher than indicated in Figure 5, the protection angle method is not applicable. For these cases, IEC 62305-3 indicates to use: rolling sphere method (valid for all types of buildings), or mesh method (indicated when flat surfaces are protected)

Applying the rolling sphere method. The location of the capture system (point or mesh) is adequate if any point of the protected structure comes into contact with a notional sphere of radius r (see Table).

metodo esfera rodante nivel de proteccion

esfera rodante puntas captadoras
Método de protección
Clase de SPCR Radio de esfera rodante r (m) Tamaño de la malla Wm (m)
I 20 5x5
II 30 10x10
III 45 15 x 15
IV 60 20 x 20

Taller structures remaining above the Faraday cage should be protected with lightning rods.