To the OP, my apologies for off topic responses. I believe anyone in the electrical industry should have a solid foundation of electrical theory. As stated in previous posts, an estimator with field and classroom training will probably " over-analyze " the estimate, and include costs outside the said scope of work. I have lost quite a few bids from this rookie estimator behavior. Most of the good electricians I know came up in an accredited apprenticeship which will ALWAYS start with electrical history and theory. Estimating is an art which cannot be taught, it is; through blood, sweat, and usually more blood; learned. However, knowledge of electron flow is THE foundation of all we do. Why not start with something solid?