Spare wires into junction box


Senior Member
I have plans which brings in brand new 120V, 208V #10 wires from 20A breakers in panelboard into junction box and then to wire mold that has receptacles or has 208V single phase load. However some of the wires in the junction box brought are spares and they do go to any load in the wire mold. They are spares and not sure they maybe used for future or not.

Does NEC 2014 or 2017 allow these spare wires to bring to junction box or not?