Went on a service call today to install some timers in a multi gang new work box in a fairly new dwelling and the grounding conductors were made up seperatly for each set of switches according to the circuit that they were fed from.I was taught that the grounding conductors must always be all connected together at each juction box even if from different circuits.

Am I correct?

What code requires the grounds to be connected together at each juction?

shortcircuit