Three Phase Line Currents from 3 Single Phase Loads

Mr. PSLACK hello!!!

"Phase A&B is 100 A ; Phase B & C is 98 A and for Phase C & A is 105 A. "

LOL, doesn't even know the difference between voltage and current...

Even more sad if he is relaying EXACTLY the way his INSTRUCTOR has worded the problem!

Sir, maybe you dont understand me. The 100A, 98A and 105A are the line currents of the three single phase loads connected to phase A, B & C. This is very important in sizing the three phase conductors that will carry these currents in our three phase source where our single phase loads are connected to this panelboard.sori if my question is not clear.

Ah! It sounds like the OP has three single-phase loads connected line-to-line (delta), with currents I_a-b, I_b-c, and I_c-a as he listed. He now wants us to tell him what the line currents Ia, Ib, and Ic into this delta will be. Sounds like a homework question to me.

You need to do a delta-wye conversion, which is not difficult. However, the quick answer, since the 3 load currents are nearly equal, is assume they are going to split pretty evenly, which puts about 100A on each phase. If you size your cables for the largest (105A), you will cover yourself. But before that, what is your bus rating of the panel? You really should base your cable sizing on that, wince someone may come after you and add to any of the loads.

Peter thanks for your comment. Our utilities in the Philippines are in DELTA-WYE distribution we are still planning to give the specs for the bus size in purchasing a panelboard for this installation.