How big a wire should be used for grounding the battery cabinet

What size ground wire do I Need?

To figure out the size of the ground wire, you consult the copper grounding conductor size chart, and you see that you need an 8 AWG copper ground wire for 3 AWG copper wire (for 100 amps, you can use 8 AWG copper ground wire). Now, there is nothing wrong if you use a 6 AWG or even 4 AWG ground wire; it will do the same job, it will just cost more.

Do I need a ground wire?

For every wire, you will need a ground wire. As you may know, the ground wire doesn't have to be as big as the main wire. Example: 1 AWG copper wire doesn't require a 1 AWG copper ground wire. It requires a 6 AWG copper ground wire. A ground wire size chart that follows will tell you exactly the size of the grounding conductor you need.

What size ground wire for 100 amps?

You can check what size wire you need for 100 amps here. To figure out the size of the ground wire, you consult the copper grounding conductor size chart, and you see that you need an 8 AWG copper ground wire for 3 AWG copper wire (for 100 amps, you can use 8 AWG copper ground wire).

What size grounding conductor do I Need?

Then consult NEC Table 250.122 to find the minimum grounding conductor size. For example, a 100-amp circuit requires 8 AWG copper or 6 AWG aluminum grounding conductor. Always use the size corresponding to your OCPD rating, not the conductor size.