Knob & Tube (K&T) Wiring
One of the earliest forms of wiring used at home is usually called Knob & Tube (K & T). This type of wiring is installed at home up to and including the 1940s. The K & T wiring system consists of 2 wires, one live and one neutral, sheathed with rubber insulation and / or fabric. In an unstoppable area, bare wires are routed through open space and attached to porcelain knobs that are nailed to a wooden frame. Since porcelain is an effective electrical insulator, the conductor is isolated from the wooden frame of the house. Where wires are run through structural elements such as studs or loops, wires are channeled through porcelain tubes acting as insulation between the conductor and the frame of the house.
With K & T wiring, if the system is in good condition it can be operated safely but there are some problems or limitations:
No Ground Security (Third Wire)
Unlike modern wiring, K & T does not have a security wire (a third wire in a modern system) that increases the odds of getting a shock or electricity. The purpose of the safety policy is to provide low resistance bonds between metal enclosures or electrical conductive parts around electrical and earth soil devices. In terms of the public, the place of safety provides direct access to the earth for electrical appliances in case of damage.
Without safety reasons, if the conductor directly touches metal housing appliance or appliance, due to internal failure, the housing will rise to the same voltage as the conductor. If a person then touches the metal housing, their body will be the most resistant to the ground and they will get a surprise. As discussed above, with ground wires, fault currents follow the least path of resistance (via ground wire) rather than flowing through the body of the homeowner.
While damage can be very large and larger than electrical wiring at home can last for long periods of time. For this reason, the circuit on current protection system such as fuse or casting) is installed to break the circuit and stop the current flow before wiring is too hot and damaged.
Without safety reasons, if the conductor directly touches metal housing appliance or appliance, due to internal failure, the housing will rise to the same voltage as the conductor. If a person then touches the metal housing, their body will be the most resistant to the ground and they will get a surprise. As discussed above, with ground wires, fault currents follow the least path of resistance (via ground wire) rather than flowing through the body of the homeowner.
While damage can be very large and larger than electrical wiring at home can last for long periods of time. For this reason, the circuit on current protection system such as fuse or casting) is installed to break the circuit and stop the current flow before wiring is too hot and damaged.
Another thing to note with K & T wiring is that two wiring systems also mean two pronged branches. This means you can not pair modern appliances with three tails without using three to two adapters, commonly known as scammers. The cheat plug is not a good idea as it allows the security feature to be avoided.
In addition, many modern electronic devices require a ground connection to operate properly and may be damaged if it is plugged into the outlet. Devices such as surge protector (to protect equipment from events such as lightning strikes) require a ground connection to provide protection that is not provided by the cheat plug.
In addition, many modern electronic devices require a ground connection to operate properly and may be damaged if it is plugged into the outlet. Devices such as surge protector (to protect equipment from events such as lightning strikes) require a ground connection to provide protection that is not provided by the cheat plug.
Is Your Home Elderly?
Since K & T wiring was not used in the 1940s, any wired C & T wiring is very old. This often means that the parts of the system have become twin, rusted, loose contact and insulation may have been damaged or damaged. Loose, rusted or damaged connections create high electrical resistance points when forced into them through heat.
This temperature can be quite hot to light the wood or insulation material that can cause a fire home. Disadvantages or degradable insulation can lead to electrical fixtures with adjacent conductors or metal structures that also produce heat and sparks, other sources of ignition for fires.
This temperature can be quite hot to light the wood or insulation material that can cause a fire home. Disadvantages or degradable insulation can lead to electrical fixtures with adjacent conductors or metal structures that also produce heat and sparks, other sources of ignition for fires.
Get it with the Times
While K & T wire provides adequate electrical services for homes in the early part of the last century, the times have changed and the house is now full of power hungry equipment (large screen tv, computer, air conditioner, electric stove, whirlpool tab, and others). The wire measure and the number of circuits used in the K & T system generally restrict the size of the service to the home up to a maximum of 60 amp.
Modern houses need a minimum of 100 amp with homes with components such as electric heat, swimming pool and air conditioning that require nearly 200 amp; To properly upgrade the K & T system for modern coder requirements, it requires complete reconstruction of the home; which can be expensive proposals.
K & T wiring is assembled and connected through solder joints without using junction boxes, which no longer fit the modern code requirements. This unfortunately does not prevent many homeowners and contractors for years from illegal and incorrect connections and leads to the K & T circuit as the rooms have been renovated and the house has grown.
The development of this circuit often causes the load of the circuit and can cause overheating conductors which, say it with me, endanger the dangers of fire. Bad junction, degraded conductor and excessive circuit are buried by invisible hazards hidden within the walls and subtle ceilings.
K & T wiring is intended to be installed on empty walls and ceiling cavities so that heat can be effectively removed to the surrounding air. Because of the insufficient and frequent homes installed by insulation, K & T wiring is surrounded (and isolated) that prevents heat generated from removing far from the conductor. Since these conductors are often overloaded, the presence of insulation will cause even worse conditions.
What you need to know if you own a house with Wiring C & T (or are thinking of buying one)
If you own a home or think of buying a house that contains K & T wiring, consider the following advice we provide to our customers.
1. K & T wiring is safe, provided it is properly inspected and maintained by licensed inspectors and licensed contractors. The Electrical Safety Authority (ESA) recommends that existing K & T conductors be concealed on the walls, floor space supplying general lighting and receptor circuits allowed to continue if:
They are covered by 15 ampere fuses or circuit breakers; and
No additional branch has been added to the original installation to load the circuit; and
The conductor, where visible, looks in good shape.
Any working K & T wiring should be checked with an inspector / contractor qualified to verify the condition and load of the circuit.
2. Ground Fault Circuit (GFCI) can be mounted on two K & T wire systems to improve system security. In two well-functioning presets the current and current flows into the containers are completely balanced and the circuit is closed.
However, if the live conductor becomes loose and shortened to the metal housing of the appliance, the outflow and inlet is unbalanced. In this case, if you hold the appliance some or all outflow will take the least path of direct resistance to the ground, right through your body and not back into the plug.
This will give you a shock that can be painful or dangerous. GFCIs contain a circuit that detects any imbalance in outgoing and incoming flow and quickly travels the circuit if imbalances exceed the detection threshold.
In Class A GFCIs, the detection level is set far below the person's threshold, thereby providing the same level of protection provided by three modern conductor based circuits. If you own a home with K & T wiring, install a GFCI store is definitely a good idea.
3. The safety of the K & T system can also be enhanced through the installation of soil bonding cables from every light fixture and exit to acceptable earth soil. (Public copper water supplies, public gas supplies, or basic rods are all examples of acceptable earthworks). In this case, all branches are replaced by three modern branches to accept the ground wire connection.
Finding this can be difficult but as it often requires ground wire to be excavated through an inaccessible area. This means that the finish walls and ceilings (lathe and plaster, drywall, etc.) should be cut to accommodate access holes that need repair after work. In my opinion, if you are going to deal with all these problems, it might make sense to just replace the circuit wiring with three modern conductor cables and mBenefits have new wires.
One Last
Many insurance companies have been attacked by fires caused by K & T systems that are not properly maintained and will not provide home insurance with K & T wiring. Be sure to ask your insurer before checking out.
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