Unbalanced 3 Phase kilns and why the amperage can be odd

A distributor asks:

On 208V 3P, why does the e23S-3 pull 34.6 amps, but the e23T-3 only pulls 27.7 amps? Is that a typo, or does it have something to do with splitting 3 phase over 4 elements?

Answer: On an e23T-3 you have three balanced circuits. There is a total of 48 amps being split three ways. A simple way to calculate this is that each phase is taking 16 amps X the 3-phase factor of 1.732 to get 27.7 amps on each phase. On the e23S-3 the full amperage of 40 amps is split between two phases with one phase unused. So 20 X 1.732 = 34.64 per phase. You take the highest amperage on any phase to get the amperage of the device.

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