Grounding electrode...

[xformer]

Where in the code can I find Grounding Electrode size requirements??

 

[augie47]

Very few grounding electrodes have a size requirement. Those that do, such as rods, are covered in 250.52
Grounding Electrode CONDUCTOR sizes are covered in 250.66

 

[infinity]

Electrode or conductor size?

Water pipe minimum of 10' buried.
CEE minimum of 20' #4 rebar or #4 cu conductor.
Ground rod 8'-5/8" or larger, 8'-1/2" if listed.