# Example of Grounding Calculation for a Server Room in the Krasnoyarsk Territory

A server room is a telecom room wherein much active telecom equipment is located. The grounding of the server room is mandatory according to the EIC. Fail-safety of the informational support and a good condition of the equipment depend on its design.

For such rooms, the required grounding resistance should not be more than 4 Ohms. The ZANDZ Technical Center has received a request to calculate such grounding system for a server room. According to the task, there should be a grounding system made of stainless steel and installed to the clay loam. Let's consider a solution offered by our engineers.

Grounding arrangement resistance calculation:

According to the engineering and geological survey provided by the customer, the prevailing soil type is clay loam.

The estimated soil resistivity is taken to be 100 Ohm ∙ m.

Horizontal electrode resistance:

Гор - Hor

where ρ is soil resistivity, Ohm*m;
b is horizontal electrode width, m;
h is horizontal electrode depth, m;
Lhor is horizontal electrode length, m.

Vertical electrode resistance:

Верт - Vert

where ρ is soil resistivity, Ohm*m;
L is vertical electrode length, m;
d is vertical electrode diameter, m;
– is depth, i.e. the distance from the ground surface to the ground terminal, m;

where t is depth of the top of the electrode, m

Electrical impedance of the grounding arrangement:

ЗУ - GA
Исп гр - Util

where n – is number of sets;
kutil is utilization ratio

Ом - Ohm
Верт - Vert
ЗУ - GA
Гор - Hor

The estimate resistance of the grounding arrangement is 3.82 Ohm, which is less than the required value of 4 Ohm.

Grounding solution

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

A set of measures to ensure the requirements for the grounding arrangement is based on the following solutions:

• the horizontal ground terminal made of stainless steel with a cross-section of 3x30 mm, 20 m long, at the depth of 0.5 m, is laid;
• 3 vertical electrodes (rods made of stainless steel having diameter 16 mm), 10.5 m long, are installed;
•  vertical and horizontal electrodes are interconnected using clamps ZZ-005-064.

Grounding equipment layout is provided in the drawing in a separate file.

Click here to view the diagram in full.

План до перепланировки - Plan before reconfiguration
Асфальт - Asphalt
С этой стороны асфальт - Asphalt from this side
С этой стороны здания необходимо выполнить заземление для серверной - Server room grounding shall be made from this side of the building
Условные обозначения - Legend
- горизонтальный заземлитель - horizontal grounding electrode
- вертикальный заземлитель длиной 10,5 м - 10.5 m vertical electrode
- зажим для подключения проводника - clamp for connecting conductors

Table 1. List of required materials

 Item No. Fig. Part number Product Amount Grounding arrangement 1 ZZ-502-303-25-H ZANDZ Stainless steel bar (30*3 mm; 25 m bundle) 1 2 ZZ-005-064 ZANDZ Clamp for connecting conductors (up to 40 mm) 3 3 ZZ-001-165 ZANDZ STAINLESS STEEL Grounding rod, threaded (D16; 1.5 m; 5/8 UNC) 21 4 ZZ-002-161 ZANDZ STAINLESS STEEL Threaded connection couple (5/8 UNC) 19 5 ZZ-003-061 ZANDZ Takeoff Tip 3 6 ZZ-004-060 ZANDZ Guide head for jackhammer attachment 5 7 ZZ-006-000 ZANDZ Conductive grease 2 8 ZZ-007-030 ZANDZ Waterproofing tape 1 9 ZZ-008-000 ZANDZ Attachment to the jackhammer (SDS max) 1

Do you have any questions regarding grounding of a server room or other facilities? Please contact the ZANDZ Technical Center!

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