Primary: The main distribution panel, supplies power from the transformer. Let's make an example for clarity: A newly constructed residential area introduces a 10kV power line to a substation. Inside, the power is split into multiple, smaller circuits that run to different areas—like the kitchen, bedrooms, lighting, and air conditioning. This box protects your home from electrical dangers and facilitates easy control and monitoring of your. The Secondary Distribution Box (SDB) receives power from Main Power Distribution box via an extender cable and provides a central power distribution to feed normal branch circuits to the electric floor modules through snap-on extender cables.