Florida InterNACHI State Practice Exam 2025 – Complete Prep Resource

Knob and tube wiring is recognized as one of the earliest methods utilized for residential electrical systems. This wiring technique, which became common in the late 19th and early 20th centuries, consists of individual wires being run through ceramic knobs and secured with tubes where they pass through wooden frame members.

The design was intended to insulate the wires from contact with wooden structures, mitigating the risk of fire. Its simplistic and effective system allowed for the distribution of electricity in homes during a time when electrical infrastructure was just beginning to emerge.

In contrast, twisted pair wiring is a category often associated with telecommunications and data networking, while Type NM cable, also known as non-metallic sheathed cable or Romex, is a more modern method introduced later, primarily used for residential wiring since the mid-20th century. Both of these methods offer different advantages and serve different purposes compared to knob and tube wiring, which is mainly of historical importance at this point.