If you mean 2/0 copper wire it is rated 175 amps. # 2 wire is 115 amps. If you are referring to 2.0 metric it is rated 15 amps.
Aluminum 4/0 wire car carry 180 amps at at 75 degrees Fahrenheit or 205 amps at 90 degrees. .
3/0 gauge
At the service entrance you will need AWG 1/0 gauge.
As a service entrance wire you need AWG # 3/0 gauge copper.
There are two distinct questions here. To determine the wire size to carry 15000 volts the circuits load amperage must be stated. The wire size for a 550 amp service is, an 800 MCM copper conductor with an insulation factor of 90 degrees C. This conductor is rated at 555 amps. Parallel 250 MCM will give you a total capacity of 580 amps. A triple run of 2/0 will give you a total capacity of 585 amps.
Aluminum 4/0 wire car carry 180 amps at at 75 degrees Fahrenheit or 205 amps at 90 degrees. .
3/0 gauge
You are probably thinking about 1/0 wire (1 ought wire). In copper it is rated at 175 amps and in aluminum 125 amps.
Each hot leg to the neutral wire of the service has the ampacity of 200 amps, that is why 3/0 wire is required. A 3/0 copper wire with an insulation factor of 90 degrees C is rated at 210 amps.
At the service entrance you will need AWG 1/0 gauge.
3/0 wire 3/0 wire
A 1/0 copper wire with an insulation factor of 75 or 90 degrees C is rated at 150 and 155 amps respectively.
No they can not, because the electrical code states that wires in parallel can only be 1/0 AWG and larger. The ampacity of 1/0 wire is 150 amps. The ampacity of a wire for 60 amps is #6 which is much smaller that 1/0 wire.
Service wire required is AWG # 3/0 copper.
The wire size used in a service entrance distribution panel is governed by the size of the services over current device. The larger the service, the larger the fault current could be, the larger the ground wire to carry the fault current to ground. If the largest service conductor carries 100 amps use a #8, 200 amps - #6, 400 amps - #3, 600 amps - #1, 800 amps - 1/0 and over 800 amps - 2/0 for the ground wire. <<>> Golden Valley Electric Assoc. in Alaska requires #4AWG copper wire for a ground from the breaker box to earth ground rod. The same goes from the service entrance panel on the pole.
250 amps maximum.
Wire is not sized by voltage. It is sized by current measured in amps. Some common copper wire sizes and their current capacities are: 15 amps -- 14 gauge wire 20 amps -- 12 gauge wire 30 amps -- 10 gauge wire 40 amps -- 8 gauge wire