# Functional Grounding for A Commissioning Area

The ZANDZ Technical Center has received a request to calculate the functional grounding arrangement for a commissioning area. Let's consider the offered solution.

Calculation data:

The soil resistivity accepted for calculations is 500 Ohm * m.

Task:

To calculate functional grounding arrangement with the resistance not more than 1 Ohm.

Grounding is made in accordance with the EIC, Rev. 7, Chapter 1.7

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

- installation of 39 sets of a vertical electrolytic grounding ZZ-100-102MB, which are combined using a corrosion-resistant steel copper-plated bar with a cross-section 30 x 4 mm;

- distance between the electrodes and from the electrode to the facility is at least 3 m, depth is 0.5-0.7 m;

- connection is made using clamps ZZ-005-064.

Ground terminal resistance calculation:

Resistance of the ZZ-100-102MB set:

Ом - Ohm
Верт - Vert

where C is a non-dimensional factor, describing the electrolyte content in the surrounding soil, 0.25;

ρ  – is soil equivalent resistivity, 500 Ohm m;

L is vertical electrode length, 3 m;

d is vertical electrode diameter, 0.065 m;

Horizontal electrode resistance:

Гор - Hor

where ρ is soil resistivity, 500 Ohm·m;

b is horizontal electrode width, 0.03 m;

h is horizontal grounding depth, 0.5 m;

Lhor is horizontal electrode length, 168 m.

Electrical impedance of the grounding arrangement:

ЗУ - GA

where n – is a set number, 39 pcs, horizontal grounding electrodes - 1 pc;

kutil is a utilization ratio of sets - 0.8; of horizontal grounding electrode - 0.7;

rated resistance of the grounding arrangement is 0,98 Ohm, which is less than the required value of 1 Ohm.

The location of the equipment is shown in Figure 1.

Комплект электролитического заземления - Electrolytic grounding set
Полоса омедненная 30х4 мм - Copper-plated bar 30 x 4 mm

Figure 1. Layout of grounding arrangement parts

Table 1. List of required materials.

 № Part number Name Quantity, pcs 1. ZZ-100-102МВ ZANDZ Electrolytic grounding kit (vertical; 3 meters) 39 2. GL-11075-50 GALMAR Copper-plated strip (30 * 4 mm / S 120 mm²; 50-meter strip bundle) 4 3. GL-11075-20 GALMAR Copper-plated strip (30 * 4 mm/ S 120 mm²; 20-meter strip bundle) 1 4. ZZ-007-030 ZANDZ Waterproofing tape 15 5. ZZ-005-064 ZANDZ Conductor connection terminal (up to 40 mm) 45

Do you have any questions about grounding of a commissioning area or other facilities? Please, contact the ZANDZ Technical Center!

Related Articles: