tube, Romex , BX, UF cables: What is 2-wire Romex, and what is it for?
Knob-and-tube The oldest wiring system you’re likely to encounter is called “knob-and-tube” (K&T). It was installed as recently as the mid-1930s. Individual wires are mounted on ceramic posts (knobs) and run along joists or studs. When the wires run through a joist or stud, ceramic tubes (tubes) protect the insulation from the wood. Wires are connected or spliced by twisting them together, soldering, and wrapping with tape. When K&T isn’t color-coded, a tester is required to identify “hot” and “neutral” wires. In general, electricians installing knob-and-tube were careful; the workmanship tends to be pretty good. The wire, insulation and insulators tend to stand up very well. Most K&T I’ve seen, for example, is in quite good condition. The distance between the wires added another safety factor: squirrels gnawing cables in your attic or basement cannot chew through the insulation in one bite and short out the hot and neutral. Since it tends to be in pretty good condition, knob-and-tube
Related Questions
- Each tube uses approximately the same electricity as a 40-watt light bulb. How many lamps do you recommend for induct home installations?
- Why do the brake cables route along the top of the top tube on Jabberwocky and Bandersnatch models?
- tube, Romex , BX, UF cables: What is 2-wire Romex, and what is it for?
