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teo Simpson, B.Bus.
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ISSN 1030-2662
4
SILICON CHIP
Wiring in older houses can be dangerous
This month , I want to talk about mains wiring in older homes , a subject
that should be covered much more often in home renovation magazines but
seldom is. It is a fact that the wiring in virtually all older homes is in a
dangerous state. I am talking specifically about any Australian house built
in the early 1950s or prior to that time. The wiring insulation in prewar
houses was cotton covered vulcanised indiarubber or, during and just after
WW II , double-sheathed tough rubber. Over the years, this rubber insulation
at first perishes and then crumbles away at the slightest disturbance.
Such wiring may operate without trouble for many years but the slightest
disturbance, such as may be caused by a possum, rat or a person moving
about in the roof area, dislodges the crumbly insulation and then you have
a perfect recipe for a fire. A lot of fires in older homes start in the wiring for
exactly this reason.
Water is a big problem too. If the roof starts to leak or is damaged during
a hailstorm (another common occurrence with older homes with their
fragile tile or slate roofs), you can have the beginnings of a roof fire. The
water runs down the wiring, seeps into the cracks in the insulation and the
resulting leakage currents heat up the insulation until it begins to smoulder
and then breaks into flame. I write from personal experience in this regard.
What is the cure? A total rewiring job is the only solution. While you are
at it, you will probably have to add in more power and lighting circuits and
the power board with its worn out and corroded fuseholders will have to be
replaced with circuit breakers. All told , it adds up to many thousands of
dollars, a major cost which is rarely considered when such older homes are
purchased.
Was your home built around 40 years ago or prior to that? If so, you should
get up in the roof and inspect the wiring. If it uses white PVC sheathing, then
it is probably OK although it may still need upgrading to give more circuits,
to allow earthed light fittings and more power ,points. But if the wiring uses
black rubber insulation, you should start getting a few quotes from your
friendly local electricians - have the job done soon because your home is at
risk.
·
Leo Simpson
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