# 10 bare copper.
# 8 copper ground wire
Use #10 copper.
#6 bare copper wire.
The ground wire should go from the dryer directly back to the distribution panel. An external ground wire is not required. The ground wire that is in the cord set that is connected to the frame of the dryer and the ground wire that is in the feeders coming from the distribution panel, that is connected to the ground terminal in the dryer receptacle, is all that is required to satisfy the code requirement.
#6 wire is needed. If placing the subpanel in a garage at a good distance, it is recommended to also install a seperate ground rod .
A typical panel has three large wires entering the main panel from the electric meter and a bare ground wire. Two of the large wires are hot and go to the busses where the breakers are mounted. The third wire is common and is connected to one or more common bus locations. It will usually be silver in color with a screw on top to connect white wires from branch circuits. The ground is the metal of the panel itself and there will be one or more ground busses usually copper colored that are connected to the metal of the panel by screws there by "bonding" these ground busses to the metal of the panel. You should also see a copper wire coming from a ground rod connected to the metal of the panel. At the main panel you need to bond the common to the ground. There is usually a screw that allows this bonding to occur. If you have subpanels ground and common are NOT connected at the subpanels.
A 200 amp service panel will require a # 4 bare copper ground wire.
Ground wire to neutral wire.
Use #10 copper.
The ground wire should come from the ground rod and to the main electrical panel grounding terminal.
#6 bare copper wire.
The ground wire should go from the dryer directly back to the distribution panel. An external ground wire is not required. The ground wire that is in the cord set that is connected to the frame of the dryer and the ground wire that is in the feeders coming from the distribution panel, that is connected to the ground terminal in the dryer receptacle, is all that is required to satisfy the code requirement.
On a 200 amp or any size service the ground wire is easily identified. Look in the distribution panel for the neutral bus bar. This is where the service neutral (white wire) is connected to the distribution panel. There you will see a bare copper wire connected to the same neutral bar. This is the ground wire that is connected to the ground rods out side of the house.
#6 wire is needed. If placing the subpanel in a garage at a good distance, it is recommended to also install a seperate ground rod .
A conductor used for grounding of the main service should be a single wire. The code book has a table that states the size of ground wire for different service panel amperages.
You do not use a ground wire in the connection from the meter base to the distribution panel. A bonding wire may be required if the service is using PVC conduit.
#8 would be fine if you ground each panel separately to the ground rod
A 3/0 copper wire with an insulation rating of 90 degrees C is rated at 210 amps.