What type of meter and test leads must be used when testing high-voltage circuits on a hybrid vehicle?

When testing high-voltage circuits on a hybrid vehicle, it is essential to use a meter and test leads that are rated for Cat III. This rating indicates that the equipment is designed to safely measure voltage in an industrial environment, including higher voltages like those found in hybrid vehicles.

Hybrid vehicles often operate with high-voltage systems, typically in the range of 200 to 600 volts or more. Using equipment rated for lower categories can pose significant safety hazards, including electric shock or damage to the equipment. Cat III rated equipment provides the necessary insulation and safety mechanisms to handle these higher voltages safely.

In comparison, other categories such as Cat I and Cat II are meant for lower voltage applications, and using them in high-voltage situations would not provide adequate protection and could lead to hazardous situations. Cat IV is typically used for overhead line work and while it is rated for very high voltages, it is not commonly necessary for automotive applications like hybrid vehicles that usually require Cat III equipment. Thus, Cat III is the appropriate choice for ensuring the technician's safety while also effectively conducting testing on high-voltage circuits in hybrid vehicles.