In 1879, Thomas Edison exhibited his new invention, electric lighting, in a neighborhood in Menlo Park, New Jersey.  Originally, this new invention was only available to the wealthiest of families. Yet, by the turn of the century, electricity inside of residences were commonplace.  

Now, 137 years later, many changes have occurred regarding electrical wiring within your home, thanks mostly, to the National Electrical Code requirements and modern technology. Contributions to the NEC code are made and revised every three years in an attempt to prevent loss of life or property due to improper installation of electrical systems. Therefore, electrical systems and wiring particularly, has evolved greatly over the years. Although much of the practices and materials that were used in the past have been phased out, much of the early wiring that was installed are still present in homes across lake Almanor and Susanville.

Do I need to rewire my home?

Countless times I have been asked by homeowners for an estimate to rewire their homes due to their “old” wiring. Many times the reason for their concerns are due to misinformation.  One should not be concerned with the type of wiring that they have as much as the instillation of the electrical components, open splices and contact of live wires with years of insulation that is not compatible with their electrical wiring.

Common types of electric wiring in your home

Knob and Tube Wiring

Knob and tube was the earliest residential wiring system used in the United States. Electricians would use individual conductors which consisted of an outer cloth braid with an inner rubber coating covering the conductor (wire). Wherever the conductor passed through any wooden Close up photo of Knob and Tube Wiring at Slusher in Chester castructure, porcelain tubes were used to deflect any heat or arcing that may occur between the wire and the wood. Also, porcelain knobs and cleats were used to support the wire as it passed along the attic to its termination point. At certain locations, it was required that the wire be spliced in order to redirect the wires to different locations. These splice points are the points that the homeowner should pay close attention to. These splice points were often soldered together or simply twisted together and then electrical tape was placed over the splice. Due to the open air installation of the knob and tube wiring, dissipation of heat was good, however these splice points would become hot and could melt the tape. Another concern with knob and tube is that in the days of knob and tube there was no insulation to speak of. During the mid 70’s it became popular to blow in insulation and contact with these splices created a fire hazard.

Cloth Braided Wire

During the 1950’s the wire industry began to transition from from the knob and tube wiring to cloth braided wire and the insulation on the wire from the gum-rubber insulation to thermoplastic or PVC rubber insulation. Rubber was very soft, so a cotton braid or wrap was added as an outer Cloth Braided Wiring in your homecovering for mechanical protection. This new cloth braided wire was actually suitable for outdoor use due to the incorporation of three braids or wraps that were saturated with a waterproofing compound. This new rubber PVC held color pigment better and would not become brittle and crack with age. The biggest concern with this type of wiring is often times the person who installed the wire would use staples to hold the wire in place and would, sometimes, hammer the staple too tight and with time the wire would become hot at that point and defect. Another concern would be that at points where the wire is terminated, the insulation should be trimmed back in a clean manner because the frayed cloth prevents a fire concern.

NM-B Jacketed Cable

nmb-jacketed-cable-slusherCurrent residential wiring applications consist of a wire called non-metallic sheathed cable or NM-B. It is used in both exposed and concealed areas of dry locations only. The conductors are coated with PVC rubber. The ground wire is wrapped with paper and laid parallel between the two insulated conductors. The entire construction is wrapped in paper under the outer jacket. This wire is approved by the NEC and the only real concern is whether the wire is terminated properly in a junction box with a cover to insure the wires cannot be tampered with.

Things to look for when inspecting your electrical wiring

Knob and tube wiring was phased out in the 1930’s yet is still present in many homes throughout the United States. It is highly suggested that, if you have knob and tube, and insulation around your knob and tube, that you upgrade your wiring. Unfortunately, cost is a factor. In the meantime, it is worth the homeowners time to inspect the tubes, knobs and splice points and look for apparent “hot spots”. All splices should be placed in junction boxes by a licenced electrician. As soon as the homeowner can afford to do so, replace the knob and tube wiring with NM-B wiring.

Cloth braided wiring should be thoroughly inspected. Check to make sure that all staples are secure, yet not so tight that the wire is being crushed. Also, if there are any splices that are not in junction boxes, they need to be. And insure that if they are in junction boxes, that they are connected in a neat and clean fashion and a cover on the box to insure safety.

NM-B wiring should be inspected and like with the cloth braided wire, all connections should be in junction boxes with covers and staples should be loose but secure.

When is it time to bring in a professional?

If you have any issues with your electrical wiring or are concerned about your home’s wiring, don’t hesitate to hire a professional electrical contractor like Slusher.  Slusher Plumbing Heating Cooling Electric is a licensed and certified Electrician and serves the Chester, Susanville and Quincy areas.  

Other common electrical services we offer:

  • Landscape lighting
  • Christmas light outlets & installation
  • Fixture installation
  • Switch & outlet repairs
  • Electric water heaters
  • Electric wall & basement heaters
  • Roof & gutter snow & ice melt
  • Home automation
  • Home theatre systems
  • Security
  • Over and under cabinet lighting
  • recessed and track lighting installation
  • Spa hookups