Purchasing a house with older Knob & Tube wiring

Knob and tube wiring simply gets its name from-A fear exists that the hot and neutral wires can
the way it's installed. There are ceramic tubes formake contact with each other (a potential fire and
the cloth covered wires that run through thesafety hazard).
wood framing of the house and the knobs are-The rubber and cloth insulation around the knob
used when the wires run alongside or next to theand tube wiring breaks down over time and
wood framing. The two wires (there is no groundbecomes brittle (a potential fire and safety
wire) are separated approximately four incheshazard).
apart. One wire is the black "hot" wire, and the-It would be too costly to maintain or even install
other wire is the white "neutral" wire (most knobthis type of wiring today.
and tube wires do not have different color-More importantly perhaps, most insurance
insulation jackets that we see in todayscompanies are now refusing to provide home
wiring). All the connections for knob and tubeowners insurance on houses with existing knob
wiring are open and visible. The wires are simplyand tube wiring that is active and live today.
spliced and soldered together with older style-Knob and Tube wiring can not be run in or under
fibrous electrical tape around the splices. If thisinsulation. This often happens when outside walls
electrical tape is not cloth covered, consider it anor attics are insulated. Older wiring was installed in
unprofessional splice. These shiny taped splicesopen spaces so that it would stay cool. The
need to be upgraded to include a junction box.insulation around the wires is made of rubber that
burns at a relatively low temperature. If
Knob and tube wiring was installed in houses upsurrounded by house insulation, the knob and tube
until about 1945, although in the rural areas up untilwires will not cool enough and could heat up
about 1950. As I already stated, knob and tubeenough to burn. It is important that if an old
wiring does not contain a ground wire. A ground ishouse is to be insulated, that all knob and tube
necessary if you are plugging in todays applianceswiring be removed and re-wired with todays
that have the third prong in the plug. However, ifromex wiring before insulation is added. This is
the knob and tube wiring is limited to bedrooms,one reason why insurance companies will not
this is not necessarily a safety hazard. Plugging ininsure homes with knob and tube wiring. They are
a two prong lamp or clock is just as safe as aafraid that home owners will bury the wiring when
three prong grounded outlet. But with todaysupgrading their attic or wall insulation.
technology (and all the three prong appliances on-Many appliances that we plug in today contain a
the market) the average family will need at leastthree prong plug. The large round prong is the
one grounded receptacle installed per room inground. Many homeowners (with knob and tube
order to make the home a much safer and morewiring) are utiluizing those little three to two prong
convenient living area.adapters for todays appliances. Those three to
Knob and tube wiring is not necessarily dangerous.two prong adaptors bypass the ground safety
If it was installed properly and the insulation jacketcircuit. This is a particularly bad idea if you are
around the wire is in good condition, and it wasplugging in a computer or television because they
not abused with over splicing and connections, anddissipate harmful static electricity through the
it is not buried in house insulation, it can provideground wire. Without a true ground, you're putting
many more years of reliable service. It is theyourself and your equipment at risk.
wiring that has been abused by homeowners that-Using knob and tube wiring for wall outlets is
make this wiring a potential hazard. On its own,where hazards are more likely to occur. Everyday
knob and tube wiring is not inherently a problem.items in the bathroom can quickly overload a 15
If the knob and tube wiring is on top of the atticamp circuit. A 1500 watt hair dryer and a 300
floor (which most are not due to insulationwatt curling iron plus a light bulb will definitely
upgrades), it could be easily nicked or theexceed 15 amps.
insulation could be worn off, causing a safety-A cost effective strategy in the older homes is
hazard. If the knob and tube wiring is in a traveledto abandon any of the electric outlets wired with
area or even in an area for "just storage", I highlyknob and tube and have a licensed Electrician
recommend that it be protected or replaced.install new grounded outlets with modern romex
Although knob and tube is a workable system,wiring. You can keep the current knob and tube
and completely safe when installed and usedoverhead lighting wiring in service. However, I still
properly, there are many concerns with thisrecommend eventually updating and replacing all of
electrical system today:this old wiring due to issues that I have already
-THERE'S NO GROUND WIRE (for more moderndiscussed.
lifestyle requirements and safety).