New IEEE Standard - Active. Standardization of circuit integrity cable testing is beneficial to cable manufacturers, distributors, and users. Uniform procedures, consistent, repeatable results, and measurable test acceptance criteria are required to allow comparisons among competing products and to allow selection of the correct product for the application. In a tunnel environment, electrical cables are relied upon to operate life safety systems. Circuit integrity cables serve as fire resistive protection for electrical circuits. Circuit integrity cables are expected to protect the electrical circuit from the effects of severe fire conditions to allow emergency lighting, emergency ventilation, and other life safety circuits to remain functional for the required time for safe evacuation of occupants and aid first responders.