A Knob-and-Tube Wiring Inspection involves checking one of the oldest methods of electrical wiring in buildings. From the 1880s to the 1930s, this was a standard method of wiring in North America. This wiring method uses knobs which help hold in copper wires insulated by ceramic tubes that run through the joist and stud drill-holes. The actual wire consists of just a hot – black – and neutral – white – wire with no ground wire. Unlike the wires used now which are contained within a plastic sheathing, both wires in a knob-and-tube wiring system must run separately to fixtures.
New constructions no longer use knob-and-tube wiring, but many older buildings might still have it throughout or in portions of the structure. A knob-and-tube wiring system uses porcelain insulating knobs, tubes and flexible non-metallic tubing for the protection and support of single-insulated conductors.
Knob-and-Tube Wiring Inspection – Exposed Wires and Conductors
The type of wiring behind the walls is obviously not visible, but very often there are exposed wires in the unfinished attic or basement. If you find any exposed sections of knob-and-tube wiring, check the outer insulation covering for broken and open sections. The insulation is often dry and brittle and chips easily.
If there are exposed conductors, cover the exposed areas with some electrical tape as a safety precaution. If no modifications are made to that portion of the electrical system, knob-and-tube wiring is considered safe, although it is obsolete.
Any modifications to knob-and-tube wiring should be made only by a licensed electrician. In addition, keep in mind that the outlet receptacles of a knob-and-tube wiring system are not grounded, so as a precautionary method they should be used only with appliances that do not require grounding.
A knob-and-tube wiring system is safe, however the downside is that it is too outdated to be used in the modern home, especially with all the heavy-duty electrical appliances commonly used nowadays. Many insurance companies are actually not willing to cover homes that have existing knob-and-tube wiring, or will cover them only at a much higher rate.
Under certain circumstances, this type of wiring may have a few problems. The insulation used is rather brittle and cannot withstand high temperatures, and if the knob-and-tube wiring has been used inappropriately it can cause the insulation to break, leaving the wire exposed.
In addition, improper splicing can also be a hazardous problem, especially because splicing into the knob-and-tube wiring is not a simple process. If you have this type of wiring in your home, it is extremely important to conduct a thorough inspection of the wiring system. A proper inspection, preferably conducted by a licensed, professional electrician, will help find the faults within the wiring. Timely repairs and proper maintenance can ensure the longevity of the wiring.
If you need to get the wiring changed, an experienced electrician will be able to replace it with copper. Moreover, you can get your entire house wiring upgraded in order to meet all the current electrical codes and standards. Look for electrical contractors who offer comprehensive installation services, including arranging for all permits and inspection, and plastering the holes they make in the walls.