Delta/star connections are available, considering only the amount of heat required, regardless of balance and efficiency. The method is that three groups are connected in parallel, and the other one can be connected to the 220 phase voltage separately, so that only one group is independent, which has little effect on your three-phase balance and will not trip.
In addition, it is also possible to use three groups, and the star point is not grounded. Although the power is reduced, it is very durable! Many large water heaters use this connection. This connection has another advantage, that is, When one phase opens and the other two phases operate as usual, the remaining one pipe is connected to a line and a zero.
If the star point is not connected to zero, the star-connected three-phase load must be balanced. Therefore, 10 heating tubes are divided into three groups, two of which can be balanced, the third group can not be balanced, and the star points must be zero. All three groups use the star connection with star point and zero. In this case, the balanced current of each of the two groups is about 18A, and the phase current of the third group is about 36A. If the incoming line is 32 square copper wire, then there is no problem, use it with confidence.
The Delta connection, the three contacts are connected to the three phase lines. The end of each element of the heating tube is connected to the end of the other element and does not affect the feasibility of this connection. The delta connection is three times more powerful than the star connection power and current. The three electric heating tube components are rated at 380 volts, such as the resistance values of the three components.