Keeping hot tub (spa) circuit line inside attic properly
In my area if the cable is for future use the current carrying conductors in the panel board must be capped and marked for future use. 
The ground conductor if bare secured to the ground buss, if insulated capped. The conductors at the other end must be in a box and capped.
I have lived and worked in 4 states and all 4 had different rules. 1 required future use to be marked and all conductors capped together.
If you remove the wire from the panel it could be considered abandoned and in most states it is to be removed. Is your panel is in the attic or a junction box?