Please review my earthing system for small data center

Thread Starter


Joined Feb 27, 2021
*Wire Size
Common Ground Terminal -> Ground 1 (10mm2)
Common Ground Terminal -> Ground 2 (16mm2)
10mm and 16mm is clamped together at some point
Lightning Terminal -> Ground 3 (50mm2)
Lightning Terminal -> Lightning Arrester/Rods (50mm2)
Ground 3 -> Ground 2 (10mm2), for prevent equipotential difference
Metal fence -> Ground system (6mm2)
Water pump and solenoid -> Ground system (10mm2)
Smart Meter -> Ground system (10mm2)
Surge Arrester 1 Phase 40kA for Each Phase -> Ground system (25mm)
Surge Arrester 3 Phase 65kA -> Ground system (25mm)
Electrical Panel -> Ground system (10mm)
Bonding wire (sensitive appliance, there is small data center inside), (10mm)
LAN Cable Surge Arrester -> Ground system (Various size, 2.5mm/4mm/6mm)
Isolation Transformer Body -> Ground system (10mm)
Voltage Stabilizer Body -> Ground system (10mm)

*Ground Electrode
Ground electrode 1, Steel 4x 13mm 4 meters
Ground electrode 2, Copper bonded rods 5/8" 3 meters + Copper rods 3/4" 4 meters (We add this electrode because we think ground electrode 1 isn't good (not standard ground rods but 8ohm resistance))
Ground electrode 3, Copper rods 5/8" 8 meters

*Ground Electrode Deep
Ground electrode 1, is 50 cm deep
Ground electrode 2, is 30 cm deep
Ground electrode 3, is 140cm deep

*Ground Electrode Distance
Ground 1 -> Ground 2 Distance = ~300cm
Ground 2 -> Ground 3 Distance = ~650cm
Ground 1 -> Ground 3 Distance = ~600cm
Ground electrode location is looks like triangle

*Surge Arrester Devices
A9L15586, for 3 phase
A9L15687, for 1 phase, each phase
For LAN Surge Arrester, I use Mikrotik and APC manufacture

*Electricity Load
Small Data Center

*Electricity System
Location : Beijing - CN.
Client : Government (Secret Location and Name).
Voltage : 220v/380v Three Phase.
Amps : 3x 100a (66000 va).
Utility's Transformer Protection : Horn Arrester, Earthed Transformer Metal Body, Lightning Rods.
Ground system : TT.
Earthed Neutral from Utility is Not Connected to Consumer Ground System (Prohibted)...
But Neutral at Isolation Transformer Secondary Winding is Earthed Grounded, also Voltage Stabilizer Secondary (Use 25mm wire size).

Please review and advise If I have mistakes in that installation.


Joined Jan 17, 2007
That grocery shop list doesn't tell much about how effective the grounding system will be. It would have to be accompanied by a detailed wiring diagram with distances between devices also shown.
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