Q: What is the difference between the R-3K and the R-T3?

A: The main difference between the two units is how they are installed. Both units use a 30mm punch hole.

The R-T3 must be wired into each phase. The R-3K on the other hand, uses the wires from an accompanying voltage indicator to receive its power. The voltage indicator wires are just routed through the R-3K which means only one wire has to be landed on each phase.