1910 Build

Still functioning;

Knob Switch

Pushbutton switch


New to old splices, code you think:)


Ah, vintage electrical…:cry:

Major Concern: The electrical system is obsolete. Improvement should be high priority for safety reasons. Unsafe electrical conditions represent a shock and fire hazard. A licensed, qualified electrician should be consulted. *** We strongly recommend that you do not undertake your own electrical repairs.***

I went a little further.
By adding this for the client.:slight_smile:
Wiring killed the deal, the Clients Insurance Carrier, State Farm, would not insure it.

Knob and Tube Wiring

Many houses constructed prior to 1950’s have what is called knob and tube wiring. One can determine if you have this type of wiring in your home, by closely looking at basement joists or attic rafters.
To determine if your home is wired " knob and tube", look for ceramic knobs or tubes in which the wire gets attached to, or passes through, joists or studs. If the knob and tube wiring is not easily visible, you can usually tell by looking at your electrical outlets and switches.

You may only have two prong outlets to plug into. Basically, no ground at each outlet or
fixture outlet means knob and tube wiring is present, likewise if you have older pushbutton switches, this is also a good sign you may have knob and tube
Nowadays, Home owners with knob and tube wiring may find it difficult or impossible to obtain insurance on their home because most insurance companies are not likely to insure a house they perceive as high risk. Insurance companies usually require a certificate of inspection and compliance from a licensed electrician, that all knob and tube has been removed and replaced with modern 3 wire grounded circuits before it will insure a home that previously had knob and tube wiring. After the electrician rewires your home, they give you a satisfactory assessment of your home, and the insurance company will consider giving an insurance policy for your house.

Overview of Knob-and-Tube Wiring

Knob-and-Tube wiring was the predominant wiring system through the 1920 s and 1930 s; some installations of knob-and-tube wiring continued in houses up until 1950. There are several distinguishing characteristics of knob-and-tube wiring in comparison to current wiring methods.
Some of the issues with K&T is:

No safety ground conductor;
Sometimes switching of the neutral conductor
In-line-splices in walls without using an accessible junction box
Often overloaded as new circuits added over time
Insulation is less resistant to damage, has a lower temperature rating, and it less water-resistant

Connections between modern wires are completed within enclosed electrical junction boxes. Knob-and-tube wiring had visible
connections. The wires were spliced and soldered together and then wrapped with electrical tape. These connections are called
pig-tail connections because one wire is wrapped several times around the other wire before the two are soldered together.
Ceramic knobs were strategically placed to protect the splice ensuring that inadvertent tugging on the wire would not stress
the electrical connection.

While the differences are considerable, there is nothing inherent in knob-and-tube wiring that makes it dangerous.
Knob-and-tube wire, properly installed, is not inherently a problem. While opinions regarding the safety of knob-and-tube
wiring vary widely, the concerns are not with the original wiring, but rather with what has happened after the fact.

Older homes with knob-and-tube wiring were often supplied with 60-amp service at the main electrical panel. They were also
subject to limited distribution in two forms: (1) limited number of circuits, and (2) limited number of electrical outlets
per room. Both of these factors opened knob-and-tube wiring to potential abuses of the electrical system after the initial

Improper alterations

Improper alterations are the most consistent problem I find with knob and tube wiring, and they pose a significant safety hazard. Unfortunately from a safety standpoint, the electrical system is one of the few things in a home that can be installed completely wrong and still work.
Additional branches improperly added to the original wiring is one of the common problems I see.
When additional branches or fixtures are added, the fuses protecting the old circuits are likely to blow frequently. Installing larger fuses is an easy, but unsafe, solution. Oversized fuses allow much more current to flow than originally intended, resulting in additional heat in the conductors. This heat causes the insulation protecting the wire to become brittle, and eventually to disintegrate.:slight_smile:

Tell your client, don’t plug anything in except a smoke detector.

It was actually to bad, the building 3 apt. was structurally sound and in good shape. For 100 years old that is. Granite foundation and all. :slight_smile:

Is that white stuff on the inside of the* subpanel* is asbestos?

I was trying to keep it simple, below is what I most likely would have reported:

Knob & Tube Wiring
Knob-and-tube wiring was used in residential electrical systems from the 1920s until the 1950s. The name comes from the ceramic knobs that are used to secure the wiring runs, and the ceramic tubes used to protect the wires where they pass through wood joists, studs etc.
Unlike modern wiring systems, where the wires run together in a single sheathed cable, the two knob-and-tube wires run separately and only come together at a terminal (switch, receptacle, fixture, junction box, etc.).
Knob-and-tube wiring is very common in older homes and is considered safe as long as it is in good repair. Unfortunately, due to its age, this is seldom the case. We often see brittle or crumbling insulation, poorly made connections, and amateur modifications, all of which can be hazardous.
Unlike modern wiring, knob-and-tube wiring does not include a ground wire. This means that the outlets served by the knob-and-tube wiring will be the older ungrounded two-slot outlets, which offer no protection from electric shock. Since modern grounded appliances (such as your refrigerator, TV, computer, etc.) typically require a grounded three-slot outlet, it will be necessary to replace some of the knob-and-tube wiring and two-slot outlets at locations where these appliances are to be used.
Knob & tube wiring has become an issue for some home insurance companies. Many companies require a passing inspection by the Electrical Safety Authority (ESA) before they will grant insurance. Some companies simply refuse to insure homes with knob-and-tube wiring. Contact your insurance company with regard to their policy on this.
If the knob-and-tube wiring is in good shape, replacement usually can be deferred until other electrical work is undertaken. However, it would be prudent to engage a qualified electrician to further investigate this wiring. Repairs should be undertaken as deemed necessary by the electrician. In some cases extensive replacement is required, which can be a significant expense.
· **Safety Issue:**The insulated sheathing covering the knob-and-tube wiring appears to be brittle. This wiring should be promptly replaced; as there is a risk of shock should someone come into contact with it. It is possible that other sections of knob-and-tube wiring not visible during the inspection may also be brittle. You should engage a qualified electrician to further evaluate this condition and provide repair recommendations. This could involve significant expense.
**· **Safety Issue:We observed poorly made connections between newer wiring and the old knob-and-tube wiring LOC. This represents a fire hazard that should be immediately investigated and corrected by a qualified electrician. All connections of this type should be performed within junction boxes, fitted with cover plates.
· Safety Issue: We observed knob & tube wiring buried under attic insulation. This type of wiring is meant to be in open air, and has been known to overheat when covered with house insulation. Concealing knob & tube wiring under house insulation also risks someone inadvertently coming into contact with the concealed wire. This represents a potential shock hazard since knob & tube wire insulation is often brittle, worn, or missing. You should engage a qualified electrician to further evaluate this condition and provide repair recommendations.
· Safety Issue, Major Concern:
Much of the obsolete knob-and-tube wiring is in poor condition. As this represents a serious shock and fire hazard, you should engage a qualified electrician to further evaluate the electrical system and provide repair recommendations. Improvements and repairs can sometimes be undertaken without wholesale replacement, although it may be a smarter long-term approach to upgrade the entire electrical system to meet modern safety standards. Extensive upgrading can be a very costly improvement.

· Investigate: Some of the original knob-and-tube wiring is still in use throughout the home. It should be noted that since the mid-1990s many home insurance companies require a passing inspection by the Electrical Safety Authority (ESA) before they will grant insurance. Some companies simply refuse to insure homes with knob-and-tube wiring. We recommend that you consult your insurance company regarding this issue.


:slight_smile: I know. Told her about it and the report said possible ACM, but only testing could confirm it.

My last two houses still had a couple (functioning) push button light/wall switches.

The 1969 vintage house I’m living in down here has no character, I miss my old places :slight_smile:

Al in TN

I live in an area with lots of old houses, but have yet to have one that the knob and tube was not updated. Good info.

Larry, this one was upgraded and advertised as being.:slight_smile:




Good info Marcel. However, I fell asleep. I’ll pick it up again tomorrow at the beach. :mrgreen: