# LIGHTING PROTECTION OF SATELLITE ANTENNAS ON THE ROOF OF THE BUILDING

Nowadays, satellite dishes are installed on the roofs of many houses, providing people with digital television and the Internet. Today it is simply a vital necessity for almost every person! However, not many people think about possible problems that may arise during a thunderstorm. At any time, a signal loss or equipment failure resulting from a lightning strike can occur.

В ZANDZ Technical Center received a request to protect satellite dishes on the roof of an office building. Let's have a look at the solution we offered.

Initial data:

• object: office building;

• type of roof: flat.

• calculate the lightning protection system of satellite dishes;

• calculate protective grounding device.

According to EIC-7, p. 1.7.103. The total speading resistance of the ground electrodes (including natural) of all repeated groundings of the PEN conductor of each overhead line at any time of the year should not exceed 10 ohms at line voltage of 380 V of a three-phase power supply or 220 V of a single-phase power source.

## Solution:

1. Lightning protection of satellite antennas is made in accordance with IS 153-34.21.122-2003 "INSTRUCTIONS FOR THE INSTALLATION OF LIGHTING PROTECTIONS OF BUILDINGS, STRUCTURES AND INDUSTRIAL COMMUNICATIONS" and AD 34.21.122-87 "INSTRUCTIONS FOR INSTALLATION OF LIGHTNING PROTECTION FOR BUILDINGS AND STRUCTURES".

2. In accordance with the technical inquiry, the object must be protected according to the 2nd category of lightning protection. System reliability must be not less than 0,95.

3. Lightning protection of the object is made in the form of a lightning protection mesh with a pitch of not more than 10x10 m, using a copper-bonded copper wire with a diameter of 8 mm (GL-11149). All towering objects are protected by air terminals masts with the height of 10 and 4 m, fastening is carried out using holders to the vertical surface.

4. Copper-bonded steel wire is used as down conductor (thickness of the copper coating not less than 70 mcm), d8mm wire (GL-11149).

5. Installation of down conductors is carried out with the help of clamp GL-11711 - on a flat roof, GL-11703А - on vertical surfaces and parapets. Distance between the clamps- from 0.8 up to 1.0 meter.

6. To connect rolled metal over the length and in the nodes, a universal clamp GL-11551A is used.

7. All metal elements, placed on the roof must be connected to the down conductor with the help of clamps GL-11545А. Stairs and hand railings are connected with the help of a clamp-bridge GL-11514.

8. Copper-bonded steel electrodes 3 m long are used as a vertical grounding electrode. A copper-bonded steel tape with the cross-section of 30x4 mm (GL-11075), which unites all vertical electrodes, is used as a horizontal grounding electrode. The distance to the object foundation- not less than 1 m. Burial depth of the tape 0,5-0,7 m.

9. In accordance with the EIC-7 ed., P.1.7.55 - Grounding devices for protective grounding of electrical installations of buildings and structures and lightning protection of the 2nd and 3rd categories of these buildings and structures, as a rule, should be common.

The calculated value of the grounding device resistance is 1.61 Ohms.

11. If there are metal reinforce concrete framings, they must be connected to down conductors/ grounding device.

12. Connection to the grounding device is carried out with the help of clamps ZZ-005-064.

Results of the calculation carried out with the software developed by the OJSC "Energy Institute to the name of G.M. Krzhizhanovsky (JSC "ENIN"):

Density of lightning strikes into the ground - 4 strikes / sq. km per year

The total number of strikes into the system in: 0.065 (once in 15 years);

The total number of breakthroughs is 0.0023 (every 435 years)

System reliability - 0,965

Probability of a breakthrough into all the system objects - 0.035

Grounding device resistance calculation:

The design resistance of the grounding device is 1,61 Ohms, which is less than the required resistance of 10 Ohm.

The location of the equipment is shown in Figure 1.

Figure 1 - Location of equipment for lightning protection and grounding of satellite dishes.

The list of required equipment and materials is given in table 1.

Table 1 - List of required equipment and materials.

 № Product item Name Quantity, pcs. Weight, kg Note 1. ZZ-201-010-3 ZANDZ Vertical air-terminal mast 10 m high with a set of 3 fastenings to the wall (stainless steel) 4 2. ZZ-201-004 ZANDZ Vertical air-terminal -mast 4 m (stainless steel) 1 8,50 3. ZZ-203-002 ZANDZ Fastening for a lightning rod to the chimney (stainless steel) 1 7,40 4. ZZ-202-001 ZANDZ Clamp to the lightning rod for down conductors (stainless steel) 1 0,20 5. ZZ-202-001 ZANDZ Clamp to the lightning rod D42 mm for down conductors (stainless steel) 4 0,43 6. GL-11149-50 GALMAR Copper-bonded wire (D 8mm / S 50 mm²; coil of 50 meters) 12 0,41 В метрах 7. GL-11149-20 GALMAR Copper-bonded wire (D 8mm / S 50 mm²; coil 20 meters) 1 0,41 В метрах 8. GL-11545A GALMAR Clamp on the gutter for a down conductor (painted galvanized steel) 30 0,112 9. GL-11551A GALMAR Clamp for connecting down conductors (painted galvanized steel) 100 0,07 10. GL-11711 GALMAR Clamp on a flat roof for the down conductor (plastic, concrete) 300 1,20 11. GL-11703A GALMAR Clamp to the facade for down conductor with its elevation above the clamp to 15 mm (painted galvanized steel) 320 0,02 12. GL-11514 GALMAR Clamp-bridge on a gutter for down conductor (tinned copper) 20 0,076 13. GL-11075-50 GALMAR Copper-bonded tape (30 * 4 mm / S 120 mm²; coil of 50 meters) 4 0,98 В метрах 14. ZZ-001-065 ZANDZ Copper-bonded threaded grounding rod (D14; 1.5 m) 16 2,00 15. ZZ-002-061 ZANDZ Threaded coupler 9 0,08 16. ZZ-003-061 ZANDZ Starting tip 8 0,07 17. ZZ-004-060 ZANDZ Driving head for a jackhammer 4 0,09 18. ZZ-005-064 ZANDZ Clamp for connecting conductors (up to 40 mm) 14 0,16 19. ZZ-006-000 ZANDZ Conductive grease 1 0,10 20. ZZ-007-030 ZANDZ Waterproof tape 4 0,40 21. ZZ-008-000 ZANDZ Header for a jackhammer (SDS max) 1 0,50

Do you have questions or if you need to calculate a lightning protection system for satellite dishes? Send your request to info@zandz.ru.