The required size of a conduit raceway for a 3-5000 mcm wire is 300 kcmil. It maximizes the limits on the wire fill for raceways.
You can pull 10 #3 gauge wires in a 2 1/2" conduit.
For new 200 amp services the conduit size should be 3 inch PVC.
A trade size hole for a 2-1/2" EMT conduit connector, the hole needs to be 2-7/8" in diameter. A 3" rigid conduit can also use this size hole without the lock nuts falling into the hole.
For a distribution panel rated at 400 amps parallel runs of 3/0 conductors will do the job.
The required size of a conduit raceway for a 3-5000 mcm wire is 300 kcmil. It maximizes the limits on the wire fill for raceways.
You can pull 10 #3 gauge wires in a 2 1/2" conduit.
For new 200 amp services the conduit size should be 3 inch PVC.
A trade size hole for a 2-1/2" EMT conduit connector, the hole needs to be 2-7/8" in diameter. A 3" rigid conduit can also use this size hole without the lock nuts falling into the hole.
The amount of conductors per conduit size example code says 3 number 4 conductors in a 1'' conduit
For a distribution panel rated at 400 amps parallel runs of 3/0 conductors will do the job.
There are two things here to keep in mind. If you are trying to add more conductors to an existing conduit run use the cross sectional area of the conduit to see if more wires can be fitted. The second thing that's relates to length is the voltage drop at the load. To size the conduit work backwards from the load amperage to size the wires. If a long distance is involved a voltage drop calculation will be needed. Then select the conduit size to accommodate the wires recommended for that load amperage. The length of conduit run is not brought into the equation on de rating wire size it is always about keeping the voltage up at the load end of the run by increasing the wire size and selecting the proper conduit size for that wire.
Conduit is just a medium to get the wires from one place to another. There is no voltage restrictions in low voltage wiring (750 volts or less). When it comes to conduit fill, electricians are governed by the electrical code conduit fill tables. The conduit is sized to accommodate the conductor size for a specific load.
Conduit is sized by the number of conductors that are being pulled into it. The conduit size of 1/2" will allow one #4 wire to be pulled into it. 3/4" will allow 2 and 1" will allow 4 #4 conductors to be pulled into it.
EMT is electrical metallic tubing. In the electrical trade there are nominal sizes expressed as a standard size. To answer your question you must state the conduit size in either electrical terms or in standard size terms to get a conversion size.For example standard size 1/2" EMT has an actual diameter size of 3/4" and the 1/2"EMT connector for the 1/2" EMT conduit needs a 7/8" hole.Likewise with 3/4" EMT the actual outside diameter is 15/16" and the 3/4" EMT connector needs a 1-1/8" hole.
The minimum size you can use is 3/4 conduit. The code allows for a maximum of 4 each # 6 gauge wires in a 3/4 inch pipe. You'll likely be running 3 ea # 6s, two hots and the neutral and a #10 ground wire.
A 3/0 wire with an insulation factor of 90 degrees C is rated at 210 amps. The electrical code book states that 3 - 3/0 wires can be pulled into 41 mm conduit (1-1/2"). Most mast kits utilize 53 mm (2") schedule 40 conduit.