It won’t be wrong to call Knob and Tube wiring the first-ever electrical wiring to be installed in homes in the 1880s lasting till 1950s, though some states had allowed for it till 1970s as well. There were reasons why its installation was not permitted any further and was made obsolete; the reasons lied mainly in safety.
Despite some problems associated, Knob and Tube Wiring abbreviated as K&T, served quite well in that time, depending upon the use and load. The use of electrical appliances has increased in the present century unlike the older times thence K&T is hardly of any use in the current era.
Understanding Knob and Tube Wiring
Knob and Tube wiring, as the name indicates, consists of ceramic knobs and tubes through which the wires run. The knob which is directly attached to some component of the household’s wire keeps it in place whereas the tube provides protection to the wire. It consists of copper conductors; one hot and one neutral, which are 4 to 6 inches apart. Wires are protected by cloth or rubber insulation. The cloth used to be soaked in Asphalt to serve the same purpose. These were referred to as ‘looms’.
The Extent Of Use Of Knob And Tube Wiring
This electrical system worked well. It was most commonly found in North America for a certain period of time but the safety of houses and individuals was always at stake. Disadvantages were simply more than the advantages thus the use Knob and Tube wiring was soon called off. Some states, however, still allow it but only after certain modifications. There is a chance that this open wire system is still installed in some old houses but its presence in any new construction is a mere impossibility. Problems of insurance can arise for the houses where this electrical wiring system is installed unless modifications are done to ensure safety and effectiveness.
Pros Of Knob And Tube Wiring
Before sneaking into what failed this system, let’s shed light on some of the amazing benefits this wiring system came with and how it met the energy needs at that time.
The conductors are maintained at a distance of 4 to 6 inches, thus can readily dissipate heat into the free air. This accounts for the handling of higher amperage quite easily.
The porcelain or ceramic insulation lasts longer and thus ensures the longevity of the attachments unless broken by any other means.
The system could easily handle 60 Amperes and it was a lot more considering the use at that time, which differs a lot from how it is now with the demand exceeding 150 amperes.
The system could be installed only by the professionals or the ones skilled. Anyone with bare minimum knowledge could not just get his hands on it and thus it was not everybody’s cup of tea.
Since there is a significant gap between the wires and the panel surface and these are held far from the framing, there are barely any chances of their rupture due to nails.
Cons Of Knob And Tube Wiring
The disadvantages are few but cannot be ignored as the consequences otherwise could be very harmful.
The insulation of wiring can be a potential fire hazard. No matter how long the porcelain knobs and tubes could last, the insulating material is very much prone to damage and may get brittle with time and ultimately start shedding.
One major disadvantage of Knob and Tube wiring is the absence of a grounding conductor which has the ability to pass excess electricity to the ground thus helps prevent short circuits and fire. This type of system consisted only of two conductors; hot and neutral.
The copper wires might get oxidized because of certain additives present in an insulator.
The conductors held apart dissipate heat. Homeowners nowadays put insulation and this insulation actually disturbs the dissipation process and could result in fire.
This system won’t serve well now because of its load capacity, demand now is far greater than its maximum potential.
With time, wires stretch and sag, ultimately become damaged to the extent that these are then of no use.
Insurance is not given in the case of houses having this Knob and Tube wiring electrical system unless certain modifications are made to meet the standards.
Call For Electrician
In case you are going to buy a house that was constructed years ago, it is necessary to look for K&T wiring. If it is there, the second most necessary step is to get it evaluated by a skilled electrician. The third most important step would be to work on all the faulty areas and fix the system for use.
An electrician could tell you of the status of the system, whether good or bad. Whether little changes would be required or it would be better to replace it with modern wiring.
People in the older times expecting greater usage would install fuses with high resistances, which used to be too high for the system and would ultimately result in damage of wires especially, due to excessive heat. An electrician would look out for that and fix it.
An electrician would replace the cracked damaged wires.
An electrician would remove the thermal insulation surrounding K&T, disturbing the heat dissipation process.
Wrapping with scotch tape or masking tape had have been a common but wrong practice. An electrician would remove those wherever seen and use electrical tape instead, where necessary.
To meet the standards and ensure safety, an electrician would replace all the outlets with GFCI (Ground Fault Circuit Interrupter) which would eliminate excess electrical flow and AFCI (Arc Fault Protection) which would prevent fires caused because of loose knobs and wiring.
It’s unlikely that you will come across Knob and Tube wiring in the present era but in case you do, it must be the one with all the necessary amendments. But, it would still come with certain restrictions such as no excess appliances should be run or wiring should not be present in the kitchen or bathroom but rather grounded. The overall repair and maintenance of K&T wiring might cost you an arm and a leg, thus evaluation of the damages and the estimation of expenses on those is necessary to have an idea whether you should be sticking with it or rather opt for its replacement.
