These blankets are designed and tested to protect a worker from blast energy, heat, and flash flame caused by faults in high voltage cable and gear, in compliance to OSHA requirements for manhole protection (29 CFR Part 1910.269(t)(7). The nature of an electric plasma arc is unpredictable therefore reference to your own work methods and practices is important. The blanket is not intended as an insulator against electric shock. It is designed to protect against plasma arc explosions.