Lightning protection of physical research laboratory

Physics research is not complete without expensive high-precision equipment. It's work should not be disturbed by interference and overvoltage arising, inter alia, due to lightning strokes. The first line of laboratory lightning protection will be the installation of an external lightning protection system. Technical Center performed exactly the same task.

To protect sensitive equipment, internal lightning protection carried out using surge protection, shielding, galvanic isolation, and other measures, is no less important. Internal lightning protection – is a separate task that we will talk about in the future.

Today's news is about external lightning protection labs. We will consider the solution proposed to the Client.

Task

To calculate the lightning protection of the laboratory.

Solution

Calculations of laboratory lightning protection are made in conformity with the following documents:

1. "Electrical Installations Code" EIC 7th edition. (further – EIC)
2. "Instructions for the installation of lightning protection of buildings, structures, and industrial communications" SO 153-34.21.122-2003 (further – SO).
3. "Instructions for mounting the lightning protection of buildings and structures" Working Documentation 34.21.122-87 (further – WD).

Interception rods were used to protect the Theater for Young Audiences from lightning strokes. Lightning discharger consists of an interception rod, intercepting a lightning discharge, the main conductor cable, and the ground electrode. All these elements let us to divert lightning current into the ground safely, without any damage to the protected facility.

The laboratory belongs to ordinary objects from the point of view of lightning protection in accordance with SO and to the 3rd category according to WD.

Laboratory lightning protection system description

A set of arrangements ensuring compliance with the lightning protection requirements is based on the following solutions:

1. The installation of four interception rods 8 m high is performed with wall fastening. It was taken into account that the fastening takes 2.5 m of the interception rod height.
2. Main conductor cables made of steel copper-clad wire with a diameter of 8 mm are laid from lightning rods, which are connected to the columns acting as main conductors using terminals ZZ-005-064.
3. The main conductor cables are mounted (installation step 0.6-1 m):
   • to the wall using connection terminal GL-11703A;

A set of measures to ensure the necessary requirements for the grounding arrangement is represented by the following solutions:

1. Installation of a grounding arrangement consisting of a horizontal electrode (galvanized steel strip with a cross-section of 4x30 mm), laid in the form of a contour around the building, depth 0.5 m, distance to the wall 1 m
2. As per clause 2.13 WR, only a circuit, without the installation of vertical electrodes is considered as sufficient.
3. The connection of horizontal electrodes to each other, as well as to metal columns is carried out using connection terminals ZZ-005-064.

The location of the elements of lightning protection system and the grounding arrangement is shown in Figure 1. The depicted protection area corresponds to area B, constructed as per Appendix 3 of WD.

Picture 1. Laboratory Lightning Protection Layout

Условные обозначения - Conventional symbols
Стержневой молниеприемник H=8 м - Interception rod H = 8 m
Горизонтальный заземлитель - Horizontal ground electrode
Токоотвод - Main conductor cable
Зажим для подключения проводника (ZZ-005-064) - Main conductor connection terminal (ZZ-005-064)

Laboratory lightning protection components

Do you have any questions about grounding and lightning protection of the laboratory? Please, contact the ZANDZ Technical Center!

CALCULATION EXAMPLE OF WORKING GROUNDING FOR AN ELECTRIC LABORATORY

SCREENED CHAMBER GROUNDING

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