Bellingham WA Home Inspector, Steven L. Smith of King of the House Home Inspection, has produced a narrated video on the old electrical branch circuit wiring system that is known as "knob and tube wiring". The video describes the history of, and some problems with, this system that was popular in the United States and Canada during the early to mid-20th century. Smith is a licensed home inspector and a licensed structural pest inspector. His firm, King of the House, Inc, is based in Bellingham, Whatcom County, WA. (revised 12/08/10 audio normalized modified edit)