History of Wiring

Posted on:

Wiring has changed a lot over the years.  Here we take a look at some of the technological advances that keep electricity running safely through your home.

Wiring is, of course, how we take advantage of the power of electricity.  Wiring systems move electricity through our homes and businesses, supplying energy for lighting and the many machines that are now so essential.  Like all technology, wiring systems and the wires and cables that comprise them have continued to improve over time.  Today we’ll briefly explore some of these.  If you’d like to know more about some of the electrical terms we’ll be using in this blog, please check here.

As hard as it might be to imagine today, some of the first wiring systems used wires that were either bare or covered with cloth.  Staples were used to attach the wires to the building’s frame or running boards.  This wires were protected with cloth tape when going through walls.  You can see an example of cloth-covered wiring here:

Cloth covered wiring, history of wiring

One of the first standardized wiring systems was knob-and-tube wiring.  In North America, knob-and-tube wiring was in common use from 1880 through the 1930s.  Insulated copper wires ran through “tubes” lined with porcelain insulation when moving through in joists and studs.  Porcelain “knobs” were attached to walls to support the wires themselves.  The wires were set up on opposite sides of structural members to protect against accidental short-circuits.

knob-and-tube wiring, history of wiring

Armored cable was originally called “Greenfield Flexible Steel-Armored Conductors” after one of its inventors, Harry Greenfield.  Two experimental versions were made, one called “AX” and the other “BX.”  (The “X” stood for “experimental.”)  The ”BX” version was produced.  Much as we often call all tissues “Kleenex,” armored cable is referred to as “BX,” even if it wasn’t produced by the trademark holders.  Armored cable is still used today for a variety of purposes.  You can see old “BX” wiring here.

Old armored or "BX" wiring, history of wiring

Armored cable was originally called “Greenfield Flexible Steel-Armored Conductors” after one of its inventors, Harry Greenfield.  Two experimental versions were made, one called “AX” and the other “BX.”  (The “X” stood for “experimental.”)  The ”BX” version was produced.  Much as we often call all tissues “Kleenex,” armored cable is referred to as “BX,” even if it wasn’t produced by the trademark holders.  Armored cable is still used today for a variety of purposes.

Romex wiring, history of wiring

In 1922, the Rome Wire Company in Rome, NY invented cable that was not sheathed in metal.  This nonmetallic-sheathed (or NM) cable was marketed under the trademark “Romex.”  Much like “BX” cable, “Romex” is still used as a broad if imprecise term for all NM cable.  An example of this type of cable can be seen here.

The wires in early NM cable were insulated in a cotton braid that was impregnated with certain substances to keep out moisture.  The insulators and cable jacket were made of other materials as textile manufacturing advanced.  These included rayon, thermoplastic, and compounded PVC.

The advancement of wiring systems and the wires and cables in them have certainly changed over time.  If you need help around your home with wiring from any era McCauley Electrical Service can help.  Give us a call at 678-362-2881 to discuss your needs.  If you have any feedback you’d like to share, please leave  a review through Google.  Hearing from our customers helps us give deliver the best service possible!