Red Blue Yellow Electrical Wires. Blue and yellow electrical wires. Conductors larger than 6 awg are only available in black and are color taped at the ends. Since red wires conduct current they are considered hot.
3 core cable was changed from red live to brown live neutral blue to neutral grey additional from yellow to black with earth bare or green yellow. This was the neutral wire. Active red neutral black earth green. Instead blue and yellow wires are used as the live wires pulled through a conduit.
Old australian colour code multiphase.
For example you might see yellow wires as switch legs to ceiling fans structural lights and outlets paired with light switches. This was the neutral wire. Blue and yellow electrical wires. I m guessing these are probably low voltage thermostat wires that come from the heater and not from a power source. While wires in these colors carry power they are not used in typical outlet wiring.