TFFN & TFN

What Is TFFN Fixture Wire?

Type TFFN wire falls under the National Electrical Code as a fixture wire. This wire has a voltage rating of 600 volts and a maximum usable temperature of 90 degrees Celsius. You can use TFFN as per the NEC for the wiring of lighting fixtures and other types of equipment where the wires are enclosed and protected. You're also permitted to use fixture wires to connect to branch circuits, although fixture wires may not be part of a branch circuit.

Although relatively flexible, the NEC requires that wires aren't subject to twisting or bending during use. There are only two approved wire sizes, 18 and 16 American Wire Gauge, with a specified maximum ampacity of 6 amps for 18 AWG and 8 amps for 16 AWG.

The Letters TFFN indicate that the wire has thermoplastic insulation, in this case, polyvinyl chloride, is a flexible fixture wire, and has a nylon jacket.