| FAA | Federal Aeronautics Administration |
| Farad | A unit of electrical capacity |
| Fatigue Resistance | Resistance to metal crystallization which leads to conductors or wires breaking from flexing |
| FEP | Fluorinated Ethylene Propylene is a melt extrudable fluorocarbon resin |
| Field | Area through which pass electric and/or magnetic lines of force |
| Figure 8 Cable | An aerial cable configuration in which the conductors and the steel strand which supports the cable are integrally jacketed. A cross section of the finished cable approximates the figure "eight". |
| Filled Cable | A telephone cable construction in which the cable core is filled with material that will prevent moisture from entering or passing through the cable |
| Filler | 1) A material used in multi-conductor cables to occupy large interstices formed by the assembled conductors. 2) An inert substance added to a compound to improve properties or decrease cost. |
| Film | A thin plastic sheet |
| Flame Resistant | The ability of a material to resist propagating a flame once the heat source is removed |
| Flame Retardance | Ability of a material to prevent the spread of combustion by a low rate of travel so the flame will not be conveyed |
| Flammability | The measurement of the material's ability to support combustion |
| Flammability Test | A test to determine the ability of a cable to resist ignition when placed near a source of heat or flame and to self-extinguish when removed from this source |
| Flat Cable | A cable with two smooth or corrugated but essentially flat surfaces |
| Flat Conductor | A wire having a rectangular cross section as opposed to round or square conductors |
| Flat Conductor Cable | A cable with a plurality of flat conductors |
| Flex Life | The measurement of the ability of a conductor or cable to withstand repeated bending |
| Flexibility | The ease with which a cable may be bent |
| Flexible | The quality of a cable or cable component which allows for bending under the influence of outside force, as opposed to limpness which is bending due to the cable's own weight |
| Foamed plastics | Insulations having a cellular structure |
| FPL | Designation of cable which meets Vertical Tray flame test for Fire Protection Signaling Systems |
| FPLP | Designation of Plenum cable which meets Steiner Tunnel test for Fire Protection Signaling Systems |
| FPLR | Designation of Riser cable which meets Riser flame test for Fire Protection Signaling Systems |
| FR-1 | A flammability rating established by underwriters Laboratories for wires and cables that pass a specially designed vertical flame test. This designation has been replaced by VW-1. |
| Frequency | Number of times an alternating current reverses itself in one second. Expressed Hertz (Hz), which is one cycle per second. |
| FT1 | A flammability rating established by CSA for wires or cables that pass a specially designed vertical flame test |
| FT4 | A flammability rating established by CSA for multi-conductor cables that pass a specially designed vertical tray fire test |
| FT6 | A flammability rating established by CSA for multi-conductor cables that pass a horizontal flame and smoke test sometimes referred to as the "Steiner Tunnel Test". |
