Mike Dolt Enterprises
Mike Dolt Enterprises
User: zcanyonboltz, Location: denver
Asked on: Sunday, May 30, 2021 at 11:38 am EDT
Answered on: Thursday, June 20, 2024 at 11:17 am EDT
Question: I'm doing two separate service changes on a duplex. There is very little space in the back of the units where the panels are going. I was able to separate 1 unit's ground rods 6 feet apart. When I do the ground rods for the other unit I can get them six feet apart.... but the question is I may not be able to have 6 feet between each separate system...any thoughts on this. Thanks
NEC Code Requirements
The National Electrical Code (NEC) requires that ground rods for separate electrical systems be at least 6 feet apart (NEC 250.53(C)(2)). This is to ensure that the ground rod systems do not effectively merge into one ground system, which could create potential safety hazards due to paralleled current paths.
Possible Solutions
In your situation, where the limited space may prevent you from maintaining a 6-foot separation between the ground rods of the two units, you have a few options: Increase the ground rod depth
Dig deeper holes for the ground rods to extend them below the minimum 8-foot minimum depth required by NEC 250.53(A)(3). This will increase the separation between the rods and the bottom of the footings.
Use multiple ground rods
Install multiple ground rods for each system, spaced at least 6 feet apart vertically. This will create a larger ground potential difference and reduce the risk of paralleled current paths.
Consult with an electrical engineer
A qualified electrical engineer can assess the site conditions and determine if there are any alternative solutions that comply with NEC requirements.
Considerations Soil conditions
The soil conditions can affect the effectiveness of ground rods. If the soil has high moisture content or is highly conductive, it may be difficult to achieve the required separation between the ground rods.
Proximity to other structures
Ensure that the ground rods are not installed too close to other metal structures, such as building footings, gas lines, or water mains. This can reduce the effectiveness of the ground rod system.
Safety
It is essential to maintain proper electrical safety by ensuring that the ground rod systems are effectively separated and securely connected to the electrical equipment.
Recommendation
Given the limited space constraints, it is recommended that you explore the option of using multiple ground rods or consulting with an electrical engineer for alternative solutions. It is crucial to prioritize electrical safety and ensure that the ground rod systems comply with NEC requirements to minimize potential hazards. Flag for review