What is the best method a fire investigator can use to verify that electrical wiring in a fire building is safe to examine?

The best method for a fire investigator to verify that electrical wiring in a fire building is safe to examine is to first ensure that the power to the building has been completely shut off at the main circuit breaker. Additionally, using a voltage tester or multimeter to check for any residual electrical current in the wiring can help confirm that the system is de-energized. It is also advisable to wear personal protective equipment and follow safety protocols to minimize risk during the examination process. Finally, consulting with a licensed electrician or electrical engineer can provide an added layer of safety and expertise.