In the technical data sheets are for components that contain plastics (connectors, switches, ...) fire safety classes according to standard UL94 indicated. This standard was originally used in the United States for the testing of plastics for electrical appliances and has now become established worldwide for the classification of the flammability and fire safety of plastics. The letter V stands for a vertically clamped specimen material of certain dimensions:

V0 means self-extinguishing after 10 seconds flaming droplets are not allowed

V1 means self-extinguishing after 30 seconds flaming droplets are not allowed

V2 means self-extinguishing after 30 seconds flaming droplets are permitted.

source: http://de.wikipedia.org/wiki/UL94