We are pulling out an old compressor and replacing it with a new air cooled package compressor. Full load amps of the package compressor is 318 Amps. There is one 4" conduit running to the old compressor I would like to reuse. Here is what I need help under standing. In the summer the compressor room stays around 100 F. The wire will be THHN. I would like to make the run a parallel run in the one 4" conduit just to make it easier to work with. If I run it parallel in the same conduit will I need to correct for 6 current carrying conductor in one conduit? Please tell me if this math is right.

80% of load.

318 Amps X 1.25 = 397.5 Amps

6 current carrying conductors 80%

397.5 Amps X 1.25 = 496.87 Amps

Ambient temperature correction factor THHN 90C column 100 F ambient 87%

496.87 Amps X 1.15 = 571.40 Amps

I need to size my wire for 571.40 Amps

Is this math right or am I going the wrong route with this.

80% of load.

318 Amps X 1.25 = 397.5 Amps

6 current carrying conductors 80%

397.5 Amps X 1.25 = 496.87 Amps

Ambient temperature correction factor THHN 90C column 100 F ambient 87%

496.87 Amps X 1.15 = 571.40 Amps

I need to size my wire for 571.40 Amps

Is this math right or am I going the wrong route with this.

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