The material condition and safety performance of a home's electrical wiring can be affected by several things; obviously age is one but structural movement's, physical damage, illegal renovations and work by non-qualified trades people commonly contribute to unsafe electrical installations.
In homes dating the pre 1960's the material quality of the electrical cabling is simply of a lesser standard by design and the overall material durability much weaker than the standard of wiring in today's homes.
Pests are a common cause of physical damage; possums and birds occupying a roof space can disturb the installation and pull cable from loosely fitted support clips and junction boxes.
The addition of a light fitting or a power point conducted by non qualified electricians or owners themselves often leads to weak links in the safety of the installation if not a complete neglect for the requirements of government and industry safety standards.
When buying a home, some quick "gut feel" judgments can be made by observing the meter box and switch board, try to note whether circuit breakers are present and if there has been an Earth Leakage Safety switch installed. Find out the age of the house and ask to view any building approvals granted for recent renovations. Look for loose power points, light switches and electrical fixtures. If these are in poor condition it leads to a more likely chance that the standard of the wiring within the house is also of a poor standard.
When engaging a Pre Purchase Building Inspector, you are not getting the standard of electrical inspection that you would from a licensed electrician but you should get additional feed back on the age and material quality of the installation, the visual standard of workmanship provided to electrical repairs and renovations. You should also get a professional opinion on the need and urgency for a new wiring installation and or recommendation for further investigation by a licensed electrician.
It is accepted and proven that the correct installation of a "Switchboard" Earth Leakage Safety Switch (ELSS) significantly increases protection against electrical shock and electrical fires. It is a compulsory requirement of certification and approval in new homes however there are a huge percentage of homes dating the pre mid 1990's that do not have an ELSS installed; at a cost of approximately $400 make sure you do.
Article written by Jason Wier B. Eng (Building) principal Inspection Angel 2007.
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