First, there is no other profession or line of work that would fully prepare you to become a home inspector. Although construction related fields require an understanding of how homes are built, they almost never deal with the extended use and age related deterioration of components that the home inspector encounters daily. You will need extensive detailed knowledge in many areas such as electrical systems, plumbing systems, heating and cooling systems, and roofing. You will also require knowledge of components that are obsolete yet still in service.
Some multi-inspector firm owners believe that anyone can be trained to perform home inspections. However, if you have absolutely no background in construction work, you are at grave risk practicing in the field. The ability to recognize conditions that may be a problem comes in part from experience with "what goes wrong." No single course, nor even a collection of courses, can prepare you for all of the significant or even life-threatening conditions that occur in the field. An inspector who fails to recognize such defects is guilty of failure to meet the due-diligence standards of professional services. Worse, an error can result in catastrophic financial loss or even death.