1. North Carolina Department of Insurance Office of State Fire Marshal
Risk Management
State Electrical Division
2017 State Electrical Code
Grounding Electrodes For
Single Family Dwellings

2. Notice:
The following illustrations are approved by the State Electrical Division of the North Carolina Department of Insurance, Office of State Fire Marshal. These illustrations are intended to demonstrate but not supersede the official written interpretations found at the following web address:
Joseph Starling
Chief State Electrical Engineer & Inspector
Illustrated by:
Danny Thomas
State Electrical Inspector

3. Only one? Or two? Date: June 12, 2018 2017 Electrical Code
Acme Meter
Subject: Grounding Electrodes for Single Family Dwellings
Section (A)(2) and (D)(2)
Question 1:
If only ground rods are used as an electrode system for a single family dwelling, are two required?
Only one?
Or two?

4. 250.53(A)(3) requires rods to be located a minimum of 6 feet apart
Date: June 12, 2018
2017 Electrical Code
Subject: Grounding Electrodes for Single Family Dwellings
Acme Meter
Section (A)(2) and (D)(2)
250.53(A)(3) requires rods to be located a minimum of 6 feet apart
(If the GEC is not continuous then 2 clamps may be required)
If more than 25 ohms then rod is required to be supplemented
25 ohms or less only one rod required
250.53(A)(2) Exception
However, the installer is required to assure this system meets this requirement and submit proof that is acceptable to the local electrical inspector
Minimum 6 feet apart

5. Subject: Grounding Electrodes for Single Family Dwellings
Date: June 12, 2018
2017 Electrical Code
Metal Water Pipe
Subject: Grounding Electrodes for Single Family Dwellings
Section (A)(2) and (D)(2)
Question 2:
If a metal underground water pipe is used as part of an electrode system and is supplemented with a ground rod, is another grounding electrode required to supplement the ground rod?

6. Date: June 12, 2018
2017 Electrical Code
Subject: Grounding Electrodes for Single Family Dwellings
Section (A)(2) and (D)(2)
Answer 2:
No. The requirement of section (D)(2) requires one supplement electrode of a type chosen from sections (A)(2) – (A)(8), in which a rod is listed in section (A)(5).
Both the water pipe and the rod must comply with the installation requirements of section (A). Because the water pipe and the rod make two electrodes, each supplement the other, thus (A)(2) is satisfied.

7. Connection must be made within first 5 feet 250.68(C)(1)
METAL WATER PIPE
Connection must be made within first 5 feet
250.68(C)(1)
(Unless permitted otherwise by exception)
Only one rod required as supplement for metal water pipe
250.53(D)(2)
METAL WATER PIPE ELECTRODE
Permitted if 10 feet or more in direct contact with the earth
250.52(A)(1)