Heres what I am wondering about. I understand the use of "FT6-plenem rated" for use in ceilings that are considered a return air duct.
The extra cost of this type of wire(station wire for low voltage burglar alarm panel connections specificly) is usuually double or more than the FT4 normal stuff.
At our local Home Depo they have in stock wire that is much less expensive than my local wire supplier but it says on the box "raceway approved...and vertical runs...." do I interpret this as the same as FT6\plenum approved? hard to find much reference to this as the more one looks the more one gets confused. Going to call the an inspection office for comments but would like comments\links of any here. Thanks to any who would comment on this.