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Proper Building Service Grounding

Proper Building Service Grounding

Proper Building Service Grounding

I wish to install 300 Amp service to a building. I am installing 3-10 ft ground rods vertically in a triangle pattern 10 ft apart. I will be bonding the rods with 1/0 copper conductor. I then will be routing the copper conductor back to the service fused disconnect.

My question is: How do I ground the service panel? Do I continue to bond from the disconnet to the service panel neutral?

The service is in conduit. How do I run the ground conductor? Do I run it bare on the outside of the conduit or place it in it's own conduit or...?

I read the code for grounding. To me it's confusing. Any help appreciated.

BTW-The building is metal. Are there any considerations here? There will be a water line but it will be PVC up to 10 ft before the building and then it will be 3/4" copper.



RE: Proper Building Service Grounding

Article 310 Table 16 75 C 350 MCM ampacity 310 amps.
Article 250 states if you have water service see table 94.
Article 250 Table 94 1/0 copper conductor for grounding electrode to be connected to cold water service pipe.
In addition to this you must take a #6 to the ground rod
The metallic water service must be in direct contact with the earth for 10 feet 250-81a.  
Since you do not have a metallic water service you can ues # 4 awg to concrete encased electrode 250-81c, or # 1/0 awg to the metal frame (columns) of building if effectively grounded 250-81b, or #2 to ground ring 250-81d.

The grounding electrode terminates at the service disconnect. If their is a neutral conductor it will also terminate at the service disconnect switch. Only at this point will the neutral be bonded to the metallic system.
The metal condit if installed correctlly will continue the
bonding of all metal components.
The distribution panel may contain the service disconnct devise, if so all bonding occours here. remember you only ground the neutral at the service disconnect.
Make sure panel is service entrance rated.
The triangle rod array needs only # 6 awg.

Hope this helps!

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