Term: FR
– FIRE RESISTIVE. To the following standards referred:
IEC 60331: Tests for electric cables under fire conditions. Circuit integrity.
The difference between Retardant and Resistive is that Retardant one resists the spread of fire into a new area and Resistive one maintain the circuit integrity and can continue to work (under specific conditions) for a time.
To know more about the most used acronyms cabling: CABLING ACRONYMS