[rbgray1]

In the above examples, if your fan circuit is running at 20amp demand, 14 gauge wire can be a maximum of 4.6 feet in length AND the connections need to be very sound to not contribute to additional voltage drop.

Since the fan relay circuit is probably closer to 6 to 8 feet in length, a 20 amp circuit REQUIRES a minimum of 12 gauge wire with sound connections and a relay capable of carrying 20amp plus. 10 gauge wire is probably a better choice in combination with soldered connections and dielectric grease on all spade connections.