Grounding and lightning protection for a medical center

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25.06.15                        , , ,

The requests for calculation of grounding and lightning protection that our technicians receive, there are cases and organization of grounding and lightning protection systems for medical institutions: hospitals and medical centers. In addition to the "standard" grounding contour for the entire electricity mains of the building, customers almost always ask to calculate a separate grounding device for the specific equipment (body scanner, X-ray, cardiograph etc).

So we decided to tell you about calculation of grounding and lightning protection for medical institutions on a real example.

It could not have come at a better time, but, recently, our technicians received such a request to identify a set of measures for the protection and operation of equipment at a medical center in Moscow.

• perform lightning protection system (step 6x6 m) and a grounding device (GD) that provides resistance of 4 ohms;
• perform separate grounding device with the resistance of 2 Ohm for an X-ray machine.

Type of soil - clay loam (100 Ohm * m), available area for the installation of an independent grounding device - 15x15 m.

The solution is based on the following measures:

1. Organization of lightning protection mesh with the help of copper-bonded steel wire D = 8 mm.
2. Arrangement of down conductors with the use of copper-bonded wire D = 8 mm. See figure below.
3. Installation of the first (4 Ohm) grounding device, which consists of eight vertical electrodes 3 m in length, combined by a horizontal electrode (copper-bonded wire D = 10 mm). The distance from the electrode to the walls of the building is not less than 1 m, embedding 0.5 - 0.7 meters.
4.

5. Проволока омедненная - copper bonded wire

6. The second grounding device (2 Ohm) is designed as a grounding mesh (copper-bonded wire D = 10 mm) consisting of four cells with the step of 7x7 m each. Vertical electrodes 6m long are mounted at the intersection points of the horizontal conductor. Embedment to 0.5 - 0.7 m. Distance from the building not less than 10 m. It is necessary to isolate the horizontal conductor (grounding device not more than 2 Ohm) at the to eliminate possible interference. See figure below.

Объект - object

Электрод - electrode

Проволока омедненная  - copper bonded wire

1. Full list of equipment:

 1 GL-11149-50 GALMAR Copper-bonded wire (D 8mm / S 50 mm²; coil 50 meters) 13 2 GL-11150-50 GALMAR Copper-bonded wire (D 10 mm / S 80 mm²; coil 50 meters) 2 3 GL-11150-20 GALMAR Copper-bonded wire (D 10 mm/S 80 mm ²; coil 20 meters) 1 4 GL-11551A GALMAR Clamp for the connection of down conductors (painted galvanized steel) 100 5 GL-11706 GALMAR Holder on a flat roof for down conductor (D8 mm; for bonding, plastic) 500 6 GL-11703A GALMAR Clamp to the facade of down conductor (painted galvanized steel) 150 7 GL-11562A GALMAR Contorl clamp for the connection of down conductors wire + tape (painted galvanized steel) 8 8 ZZ-001-065 ZANDZ Copper-bonded threaded ground rod (D14; 1,5 m) 52 9 ZZ-002-061 ZANDZ Threaded coupler 36 10 ZZ-003-061 ZANDZ Starting tip 17 11 ZZ-004-060 ZANDZ Guiding head for a breaker hammer 11 12 ZZ-006-000 ZANDZ Conductive grease 4 13 ZZ-008-000 ZANDZ Breaker hammer header (SDS max) 1 14 ZZ-005-064 ZANDZ Сlamp for conductor connection (up to 40 mm) 20 15 ZZ-007-030 ZANDZ Waterproof tape 5

The activities are carried out in accordance with the EIC 7th ed., industry standard 153-34.21.122-2003 "Instructions for lightning protection of buildings, structures and industrial communications" (hereinafter industry standard), and AD 34.21.122-87 "Instructions for lightning protection of buildings and structures".

Will you also need calculation of grounding or lightning protection? Contact us and we will surely help!

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