Good evening: I have replaced all receptacles in teh past 3 homes I owned. Recently bought a home built in 1968. I attempted to replace the kitchen receptacles with GFCIs. However, when I pulled the existing receptaclres from their boxes, each contains 2 black, 2 white and 2 red wires. I assume the red are hot like the black, but what are they and how do I wire the line and load of the GFCI?
Thank you for your time.