Kirchhoff's junction rule (KCL) is a consequence of:

1. KCL: Σ I_in = Σ I_out at any junction; equivalently, net I in = 0. 2. Charge cannot accumulate at a point in a steady current, so total charge entering = total leaving. 3. Kirchhoff's voltage rule (KVL), by contrast, is conservation of ENERGY around a loop. _Source: syllabus Physics Ch 3 §3.9 Kirchhoff's Laws_