Book updated Apr 2024. NEC 2020 has just been adopted here. We create these self-practice test questions (220+ questions) referencing NEC established technical standards (as well as a little bit of state specific licensing/OSHA requirements) currently valid in the trade. Each question comes with an answer and a short explanation which aids you in seeking further low voltage related technical information.This product focuses on the technical aspect of low voltage works in general. It does not specifically cover fire alarm, satellite or other specific disciplines. You should therefore use this product together with other study resources for the best possible exam prep coverage.