Week 26 - Miles of Electrical Wires

The construction is still moving at a very nice pace - sadly, the pictures just don't show how hard everyone is working. Below are some pictures that hopefully capture the miles of electrical wires that are being installed. Good thing is that now the house will have a solid electrical system instead of the knob + tube system that was originally in the house. 

Week 25 - Plumbing

It may seem like baby steps, but this week we saw major movement on the plumbing.  It is amazing the amount of yardage of copper and galvanized pipes that are required for providing water throughout the house and taking waste away.  Below are a few photos of the plumbing as it is being installed.

Week 24 - Fire Sprinkler System

While the installation of the siding continued on the exterior of the house, the plumbing subcontractors were busy this week installing the fire sprinklers throughout the house.  In the below pictures you can see all the fire sprinkler lines in orange tubing with spray heads being positioned in the ceilings of all the rooms.

Week 23 - Corner Window

This week the installation of the redwood siding continues on the house and we finally saw one of our favorite elements of the Park Hill facade begin to take shape.  Below is the original rendering and in the lower left hand portion of the house you can see a small transom-style window.  The intent behind this specific window was for it seem as if it was carved out of the redwood siding.  The following pictures show the meticulous installation of the redwood to achieve this intended look.

Knob + Tube

One of the more interesting aspects of the house we uncovered after the demolition was the knob and tube electrical wiring system.  Knob-and-tube wiring (sometimes abbreviated K&T) was an early standardized method of electrical wiring in buildings, that was commonly used in North America from about 1880 to the 1930s. Below are some images showing the components that made up the knob and tube system.

The individual conductors (wires) were run spaced apart at least 2-1/2 inches (if exposed), but as the wires passed through walls and floors, they could be susceptible to dampness and abrasion, which could eventually lead to leakage of current and potentially, arcing fires. For protection in these places, “insulating tubes” were used. These tubes were made of porcelain, with a flange on one end and set on an angle to prevent the tube from sliding through the hole. The below figure is an illustration showing the placement of tube through a stud and supporting a wire.

To support the individual conductors in other places, a wide variety of insulators, including porcelain knobs and cleats were used. These were nailed to the wood structure, and would have a leather washer under the nail head to prevent the porcelain from being cracked when it was hammered in place. 

Although knobs had two grooves, they could not be used to support two wires of opposite polarity. However, cleats could be used when wires were run in parallel. In addition to keeping the wires spaced apart, these knobs and cleats also helped keep the conductors away from wood and other damp surfaces, as well as providing a degree of strain relief. Where free ends of wire attached to boxes, fixtures, and other devices, a special water resistant cotton braid tubing known as “loom” was used to cover the wire. 

Historically, wiring installation standards were less stringent in the age of knob-and-tube wiring than today. Compared to modern electrical wiring standards, the main shortcomings of knob-and-tube wiring are: knob-and-tube wiring never included a safety grounding conductor; did not confine switching to the hot conductor (the so-called Carter System places loads across the common terminals of a three-way switch pair); and it permitted the use of in-line splices in walls without a junction box (and thus exposing a potential fire hazard of an uncontained spark caused by arcing following mechanical failure of the splice). Compared to modern thermoplastic wiring insulation, the K&T wiring was less resistant to damage.

Knob-and-tube wiring systems began being phased out in the 1930’s, probably because of the then growing popularity of non-metallic and armored cable systems for residential buildings. Knob-and-tube wiring has not been permitted for new installations since the mid-1970’s.

Below are some pictures of the existing knob and tube wiling system in the house before it was removed to make way for a more updated up-to-code wiring system.

Durring the demolition we collected the porcelain tubes throughout the house.  Once we move into the renovated home we will figure out  way to highlight them as a small piece history from the house.