The OP said he was going for an electrician's position; not an EE position, or anything else where showing off electronics prowess was needed. I'm willing to bet the answer was "use a transformer rated for the input voltage and current needs"; unless the OP is using the term "electrician" to mean something else...
I do agree, though, that if you are going in for an interview, and the competition is tight (or you think it will be), having a portfolio and/or physical project with you will make you stand it; you are there in the interview to sell your skills and your knowledge to the employer - they'll remember the competent guy with the project.