How to wire a relay into a circuit?

I am setting up a home automation setup to allow me to turn on my hot tub over the phone. I am going to use a telephone controller from Honeywell (http://www.aubetech.com/products/produitsDetails.php?noProduit=46&noLangue=2) and a relay I bought from McMaster. The relay says the control voltage is 20–60 volts. Does this mean when I connect it to the Honeywell box that it will ONLY send the 20 volts the relay needs? The wires wont be in conduit and will be running through my walls. I want to make sure I wont start a fire!