Electrical Instruments in Hazardous Locations is a clear and practical guide for maintaining the safety of electrical instruments in areas where flammable gases, vapors or dust may be present. It explains the science of combustion and ignition in simple terms, then demonstrates how this science informs real-world safety decisions, such as classifying hazardous zones and choosing protection methods, including explosionproof enclosures, intrinsic safety, pressurization, sealing or encapsulation. This book also includes practical chapters on device and system design, testing and the documentation necessary for approvals, as well as specific concerns like ignition by light or dust, and balancing safety, cost and functionality. Additionally, it explains how standards agencies create rules for safe electrical equipment and installations in hazardous (flammable) environments, and how these rules have developed into documents used for legal compliance and product approval.