Pre perchase home inspection

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Home Inspection Reveals Aluminum Wiring Problem
or Not?
Does a Home Inspector Check for Aluminum Wiring?
We inspect a lot of homes in San Antonio, and
its not uncommon to find segments of the
electrical wiring that are made of aluminum,
especially in the older areas closer to the city
center. Aluminum wiring isnt inherently dangerous
by just existing, and in fact its still used
today for service conductors, but the way that
aluminum wiring is installed and the precautions
that must be taken into account for it can lead
to problems when everything isnt in place. home
inspection san antonio What is Aluminum Wiring,
and Why Was Aluminum Wiring Used? During the
early 1960s, the price of copper rose
significantly in a short period of time. Multiple
factors contributed to the steep increase in
copper prices, including the Vietnam War, a
housing boom, and a production limit set in
place by producers to raise profits. As
electrical wiring is a necessary material for new
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housing, increased copper prices increased the
price of building a home, and a cheaper
alternative was sought.
Aluminum wiring was the answer to soaring copper
prices. Although aluminum is only 60 as
effective at conducting electricity as copper,
the reduced density of aluminum made the wire
lighter, and aluminum is significantly more
abundant and thus cheaper than copper. The
decreased conductivity required the use of more
metal to be used in the wiring, increasing the
gauge (or size) of the wires, but at the time,
the cost of aluminum was so cheap that it just
made economic sense to work with aluminum instead
of copper, and manufacturers did so. An
estimated two-million homes were built primarily
with aluminum wiring between 1965 and 1972.
Why is Aluminum Wiring A Problem? As mentioned
earlier, aluminum wiring is not inherently a
problem, so long as the the differences between
it and copper wiring are accounted for. All the
overhead wiring used by power companies in San
Antonio has been aluminum for decades due to its
low-cost and light weight, and aluminum is still
used for the incoming service conductors on
homes built to this day.
The issue is that these differences werent
accounted for in the installation of aluminum
wiring in the 1960s and 1970s.
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Aluminum Wire Deforms and Arcs For instance, the
almost pure-aluminum alloy used in large overhead
wires carrying huge amounts of energy expand and
contract at a much higher rate than copper. As
energy passes through the wiring, the wires
temperature increases due to electrical
resistance, and as the temperature of the metal
increases, so does its size. The copper wire
does not have as much electrical resistance as
aluminum, so it doesnt heat up as much, and
thus it doesnt expand at nearly the same rate.
The expansion and contraction of the aluminum
wiring, known as creep, caused problems when
used on connections designed with the properties
of copper wiring in mind, such as receptacles.
This wire creep and deformation could actually
cause the wire to become loose from the
connection over time, which further increases the
electrical resistance and would eventually lead
to arcing, creating an ignition source for
fire. This meant that over time, any connection
made between aluminum wire and another component
not specifically designed for aluminum wire
could be a fire hazard. Aluminum Wire
Corrodes Aluminum wire is also much less
resistant to corrosion than copper. Over time,
exposed copper wiring with energy flowing
through it could corrode in the presence of
simple water vapor, such as from a room
humidifier or even cold-air leaking in from an
exterior wall. These corroded wires are much more
resistant to the flow of electricity than
non-corroded wires, creating more heat and
eventually an ignition point.
Aluminum Wiring and Home Inspections
Yes, any aluminum branch wiring discovered during
the course of a home inspection in San Antonio
will get documented on the report. At that point,
we will always recommend that a licensed
electrical contractor evaluate the extent that
aluminum wiring was used throughout the house and
make recommendations as to the solution.
As a home inspector in San Antonio, we are
required to check that any aluminum wiring
connections are made with an anti-oxidant paste
(typically black in color), in order to minimize
the oxidation at the contact point. In this
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case, we most often see aluminum wiring in main
breaker panels or breaker sub-panels, used as
service conductors leading into the
panel. Does Your Home Have Aluminum Wiring?
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