Specifies requirements for two classes of insulating mat to protect personnel where circumstances involve the possibility of contact with conductors or electrical equipment whose nominal voltage does not exceed 650 V whether a.c., r.m.s. or d.c., between conductors or between conductors and earth. Does not cover the safe and proper field use of insulating mats, and does not apply to insulating mats rated at greater than 650 V nor insulating covers.