Remote Switch wiring for a gas log fire place
I thought any time you came within 18" of a stove or insert (fireplace type) you were supposed to use "glass" or high temp appliance wire (but this may be an Oregon thing).  It is about a buck a foot here in the pacific northwest. You only need a small gauge to control your gas valve; 18 would probably do just fine but it may be easier to find 14awg.  The wire I am talking about has a glass braid on the outside and some type of plastic inner insulation, this type of wire can handle the heat unlike standard AWM/NM/THHN. Plumbing and electric stores usually have it; I'm not sure about the big box stores.