Assuming that the question is being asked about "dirt"; in the United States, the volume of dirt is calculated in cubic yards. In the rest of the world, the volume of dirt is calculated in cubic meters.
A cubic yard of dirt is the volume of dirt that fits in a space 1 yard (36 inches) by 1 yard by 1 yard.
A cubic meter is 1M X 1M X 1M.
Yes, there are ground wire gauges. The approiate size ground wire must be matched to the size service you are installing. For instance a 200 amp serivce must be grounded with a # 4 bare copper ground wire.
# 10 bare copper.
Use #10 copper.
A 100 amp residential service requires a size #8 copper wire, it should be insulated in green.
#6 bare copper wire.
To calculate the wire size, a system voltage is needed.
A #14 wire will do fine for grounding a 20 amp device. That is the size of the ground wire in a 2 conductor # 12 wire building cable.
Yes, there are ground wire gauges. The approiate size ground wire must be matched to the size service you are installing. For instance a 200 amp serivce must be grounded with a # 4 bare copper ground wire.
The ground wire in a two or three conductor #12 cable is a #14 bare ground wire.
A 200 amp service panel will require a # 4 bare copper ground wire.
Yes, as long as it is the same size wire or larger as the hot and neutral wires.
Yes, NEC has an entire chart on grounding.
1/0 copper
# 10 bare copper.
six awg
Use the National Electric Code wire size tables for various applications.
How to calculate a cable size of 3kw motor