Hi...
Can I add on to or extend the main cables in the house to install a dishwasher (the power box on the dishwasher is on the far side and the main house (hot, black, ground) wires don't reach..

Thanks ~ Janet

I don't understand the question. The main incoming power wires have nothing to do with the circuits. You cannot tap into the main lines for a circuit. That is what the breaker panel is for.