3-Phase to 1-Phase Amperage Draw

Single Phase Watts = Volts x Amperes x Power Factor

Three Phase Watts = Volts x Amperes x Power Factor x 1.732

Single phase at 208v = 9.6A

Three phase at 208v = 5.54A

Thank you for your responses.

single phase= 2000/208

three phase= 2000/208/3

assume heaters are resistive not inductive nature

To adapt this heater between single phase and three phase, it would require 3 separate elements which are assumed to be resistive so there is no Cos component involved in the calculation.

In single phase mode the three separate elements would be combined in parallel with a total load of 2000W/208V = 9.6A.

Because you are quoting a 3 phase Line voltage of 208V which is the same as the phase voltage, the resistance/voltage relationship per phase is equivalent to one element at 65ohms and as there is no benefit of a higher voltage on the three phase supply then the phase current is the same 208/65 = 3.2A per phase.

When the higher voltage is not applicable the 1.732 component does not apply.

Did you mean to state 208V - 3 phase?

Uh . . . At what voltage is the heater rated for 2000 W? If it's a 240 V heater rated at 2000 W, then it won't put out 2000 W at 208 V. 208 V is 208 V whether it's 1 phase or 3 phase.

Bill is correct.

The element resistance is designed according to the rated design voltage of the equipment and the correct answer to your question requires the original rated voltage.

Your other replies are also correct - on the basis of your information the single phase current is 9.6A

If the element is Star connected to a 3 phase -4 wire supply, then the phase current is 3.2A

If the elements are Star connected to a 3 phase 3 wire supply the phase current will be 1.85A

If the elements are Delta connected to a 3 phase 3 wire supply the current will be 5.5A.