Pressing power on the microwave causes the lights to flicker and brewing a cup of coffee blows a fuse. The room is darkened by the lack of electricity. Finding your way down to the circuit box to flip a switch is no easy task. This is a common problem in many homes throughout the Duluth community due to the original electrical wiring. "It's generally in the kitchen," said Elsa Swenson, a tenant in Duluth. "If you try and run the electrical tea kettle and the toaster at the same time, the power goes out in most of the house."
There are only two electrical outlets within her kitchen. The lights in the stairwell flicker and the power goes out in the bathroom if too many appliances are plugged into the outlets.
“When they originally built a lot of these homes, they had what you call knob and tube wiring,” said Linus Olson, owner of Electric Builders, a company located in Hermantown.
According to livingwithmyhome.com, knob and tube wiring is one of the oldest techniques used to electrify residential homes.
Many of the homes in Duluth were built between 1920 and 1950. Knob and tube wiring was the predominant wiring system through the 1920s and 1930s. If the original wiring is not tampered with, it can still successfully carry electricity throughout a home. Olson says most of this wiring should have been completed in an attic. The wires can be placed inside the walls as long as it’s not insulated. This is because the insulation on the wire cannot handle high temperature environments.
“In other words, you cannot cover it,” Olson said.
Olson said they did a good job with building and wiring many of the homes in Duluth at the time with the materials they had to work with. According to knobandtubewiring.com, many homes with this type of wiring are subject to limited distribution of electricity. This is because there was a limited amount of circuits and a limited number of electrical outlets per room. Knob and tube wiring is not a grounded system and cannot be used to wire modern electrical outlets.
Scott Marshall, owner of Marshall Hardware, says it might be best to call an electrician and have them re-wire the home if it is still equipped with knob and tube wiring.
“It is very safe and works great,” Marshall said. “But it doesn’t adapt well to modern wiring.”
This electrical wiring can be found in basement joists, or supporting members that run from wall to wall or to the nearest support beam. The wire is usually attached to ceramic knobs or tubes. Push button switches are also a sign that knob and tube wiring can be found throughout the home.
Home owners usually have a difficult time obtaining insurance since a home with this type of wiring can be perceived as high risk. Companies require a certificate of inspection and compliance from a licensed electrician. Often times they require that all knob and tube wiring is removed and replaced with moderngrounded circuits before the home can be insured.
According to the National Association of Certified Home Inspectors, there is no code that requires this type of wiring to be completely removed from the home. The only dangers from this system arise from its age, improper modifications, and areas where building insulation covers the wires. Many electrical problems occur when this type of wiring is overwhelmed by numerous appliances since it cannot service three-pronged appliances.