What is the maximum run length of an 18AWG fixture wire tapped onto a 20A branch circuit?

The maximum run length of an 18AWG fixture wire tapped onto a 20A branch circuit is 50 feet. When determining the appropriate length of wire to use, one must consider the wire gauge, the current it needs to carry, and the associated voltage drop over that distance.

In this case, 18AWG wire is generally rated for a certain amount of current, which is notably less than that of thicker gauges like 12AWG or 14AWG. For a 20A circuit, using 18AWG wire means it has to be short enough to minimize the risk of overheating and excessive voltage drop.

The National Electrical Code (NEC) indicates that the wire should not exceed certain lengths when connected to branch circuits to maintain safety standards. For an 18AWG wire on a 20A circuit, the maximum length is specifically set at 50 feet. This ensures that while the fixture wire is operating, it remains within safe temperature limits and allows for a sufficient voltage level to reach the fixtures without significant loss.

Thus, recognizing the implications of wire gauge, current, and length is crucial for electrical safety, and in this context, the correct run length for 18AWG wire tapped on