In fact, the ground resistance is the criterion to determine whether the grounding rod is in a level state after it is connected to the ground, and the ground resistance contacted varies with the depth of the grounding rod. Generally speaking, the length of the grounding rod should not be less than 240 centimeters, that is, 240 centimeters. Moreover, most importantly, unless there is a proper protective device at the top of the grounding rod, the upper end of the grounding rod should be horizontal or lower than the ground. If you want to reduce the ground resistance when grounding, you need to use a longer grounding rod or use more than two grounding rods. If the latter is chosen, the distance between the grounding rod and the grounding rod should not be less than 180 cm.
But traditionally, the grounding rods of electric power and other electrical appliances are 2-2.5m. Basically, it is one dozen. It is suggested that the 2.5 inch pipe be used to sharpen the head into the soil with more moisture. According to probability statistics, the Pearl River Delta can basically satisfy the value of 4-5 Euros.
In summary, the grounding rod should be buried underground in general, so the depth of the grounding rod buried underground depends on the overall length of the grounding rod.