This is highly dependent on the source voltage and expected current. This cannot be done by an amateur. Find a competent electrician for this installation.
Use #10 copper.
#6 bare copper wire.
AWG # 3/0 copper.
# 10 bare copper.
A 200 amp service panel with a 60 amp sub-panel.
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.
The wire size in a meter stack is governed by the size of the first over current device.
Yes, they are the same size wire.
bed
The price per meter of electrical wire depends on many things like the size, type and many others. The prices vary from $0.1 per meter to $200 per meter.
Use #10 copper.
The voltage of the solar panel is less important than the total amperage. Proper wire size is determined by amperage that will be going through the wire. Wire INSULATION determines the voltage that a wire can carry.
Copper SE cable gauge 00 from the meter socket to the breaker panel for a 200A service. Then 8, 10, 12, and 14 gauge wire depending on the load.
A 200 amp service panel will require a # 4 bare copper ground wire.
#6 bare copper wire.
The wire size is dependent upon the wattage size of your water heater. The higher the wattage the larger the wire size. A standard 3000 watt heater will use a two pole 20 amp breaker connected to 2C #12 wire.
AWG # 3/0 copper.