what is the voltage on a Cat5 computer net cable? I have a situation where we stubed up a conduit and a J box and run a 18-3 t/stat wire for a zone sensor for a HVAC system and then the network cable guy decided to run 2 cat5 wires down my conduit, i am having problems with the zone sensor not reading right should be about 1.5 volts @ 70 deg, could the cat 5 wire induce a higher voltage and cause me problems?