How to calculate the current of the heating tube delta connection and star connection?

1. First, follow the triangular connection method, that is, according to the three electric heating tubes as a group, the first connection is connected in a triangular shape, so that the wiring power supply is 380V, and the single rated voltage of the heating tube is also 380V:

The voltage E between the lines is equal to the phase voltage EP

Current between each phase IP=E/R

Phase power PP=E^2/R

The total power P is the sum of the power of each phase P=3PP=3E^2/R

The line current is 3 times the line current

2. Star connection, that is, the power supply is 380V, the rated voltage of a single heating tube is 220V, and each of the three heating tubes is connected.