With no load on a circuit, I measure approx 15volts
Is this normal 


It is most likely a capacitatively coupled voltage from "hot"/"live" wires running adjacent to the wire being measured using a high-impedance multimeter. If your meter has a "low-Z" setting, try that. If the voltage is zero using a low-Z setting, there is nothing to be concerned about.

See


Fluke - Ghost Voltages
NEMA - Phantom voltages



  Due to the high impedance of measuring instruments, a voltage reading may be 
  detected on open conductors where there is no hard electrical connection to a voltage 
  source. Conductors that are installed in close proximity to one another, and are 
  capacitively coupled to each other, can cause this a.c. voltage reading. Such a reading 
  could be 2 or 3 volts, or it may be as high as the voltage on the adjacent conductors. 
  This is what is referred to as a “phantom” voltage.
  ...
   NEMA recommends the use of a Listed low impedance multimeter in 
  place of a high impedance multimeter or other high impedance measuring device for 
  testing on open conductors where there is no hard electrical connection. Without a low 2
  impedance measuring device, a high voltage reading is an inconclusive indication of 
  possible faults in the cable