# Adding second ground rod. Is this an acceptable way of bonding?

I recently found out that our sole ground rod is only 4 feet long. That said, I want to add a properly-sized ground rod to "improve" the grounding system and hopefully comply properly with the electrical code.

Our current electrical system is the one in blue, where M is the meter, B is the breaker. Both are grounded via #8 wires connected to the ground rod. The ground bus bar in the main panel is also connected to the ground rod via a #8 wire.

The existing ground rod is in front of the house. However, there isn't much space in front to place another rod there. That said, I'm planning on putting the additional rod at the back of the house. In effect, the two rods will be around 20 meters apart.

Now, the question is: Can I just run a #8 or #6 wire from the 8-ft ground rod back to the Main Panel and just bond it to the ground bus bar, in effect bonding the two ground rods? Or do I need to run a separate wire all the way from the 8-ft rod to the 4-ft rod? Note that the Main Panel will be closer to the 8-ft rod. They will be just 7-8 meters apart.

• Is there any chance of replacing the existing ground rod instead? In the event of a lightning strike nearby there could be a very high potential difference between two rods. Cows can be killed like that, and their legs are less than 2 meters apart. Advice for humans caught outdoors with lightning nearby includes keeping one's feet together. Mar 10, 2017 at 12:36
• @AndrewMorton -- that's not an issue if the two rods are solidly bonded together. The reason why two isolated rods can have a high potential difference in a lightning scenario is because the conductivity of ground is quite poor compared to that of #6 copper wire -- in effect, what's going on here is that the potential difference between the two rods is "shorted out" by the grounding system. Mar 10, 2017 at 12:47
• What you are calling the main panel is really a sub-panel, and should have a 4 wire feeder from the breaker under the meter, which in this case is the actual main panel. Your additional ground rod should connect back to that main breakers panel, even if it's just a single breaker enclosure. Mar 10, 2017 at 13:05
• @ThreePhaseEel Thanks, the information regarding the relatively low conductivity of the ground is a good point. Mar 10, 2017 at 14:36