Failures of underground cables and accessories can result in the release of toxic gases and large amounts of energy. These failures include smoking manholes, manhole fires and manhole explosions. These failure events can damage underground infrastructure and pose a risk to the maintenance crews and the public.
The guide examines the root causes, prevention, early detection, mitigation and response to failures of accessories and cable inside of, and connected to underground electrical structures (i.e. manholes, vaults, handholes, etc.). It suggests methods that can help prevent manhole events from occurring and identifies methods that can mitigate the severity if a manhole event should occur.