Ground Rod Resistance Testing

Ground Rod Resistance Testing
How to test the ground rod resistance. Code requires a second ground rod if the ground resistance is more than 25 ohms.

Also, the code does not specify the diameter of ground rods above 1/2”. It does say that if the rod is not UL listed then it needs to be at least 5/8” in diameter. Any ground rods you may be required to install that are larger than 5/8” will because the specs ( the Engineer) has called it out as a requirement.

The Code also states that for driven rod electrodes, the electrode conductor does not need to be larger than #6 copper.

Table 250.66 is for sizing all other electrode conductors and bond jumper.