Protecting your home electronics

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These days we rely heavily on our home electronics for communication, entertainment, work, study and storage of photos and music. However there are serious risks to that equipment - and data - from power surges and lightning strikes.

In Australia, we generally experience a very reliable electrical power supply. However there are serious risks to our home equipment from power surges and lightning strikes.

Power surges

In Australia, we generally experience a very reliable electrical power supply, with the supplied voltage well regulated by various suppliers across Australia within a range between 207 and 264 voltsi. However, from time to time there are power surges and sudden dips which can cause damage to electrical equipment. These events can be caused by factors beyond the control of power suppliers such as storm damage to infrastructure, or damage caused by wildlife, vehicle accidents, bushfires or vandalismii. Energy suppliers may well claim exemption from damages caused by power fluctuations resulting from such incidentsiii.

Lightning strikes

Thunderstorms and lightning pose an extreme risk to electrical equipment - indeed they also present real personal injury risk when using equipment which is connected to either the power supply or a telecommunication line. Unsurprisingly, electronic equipment which is attached to either, such as computers and fax machines, are particularly vulnerable to damage from a lightning strike.iv

Preventative measures

There is no absolute protection against damage from direct lightning strikes because of the enormous energy and high voltage - approximately 300,000 voltsv - involved. Wherever possible, the best defence is to disconnect equipment from power and telecommunication supplies until a storm or other risk to supply has passed.

Thunderstorms and lightning pose an extreme risk to electrical equipment and can also present real personal injury risk.

In cities and heavily built up areas, the density of surrounding infrastructure can often dissipate the energy of a lightning strike. However, in rural areas or on the edge of a built up area the risk of damage is far greater; in such zones it may be necessary to engage a licensed electrician to install a Surge Protection Device (SPD) on the main power supply. Telecommunication network providers can install protection to the telecommunication supply by installing a gas discharge tube (GDT) to the supplyiv.

Both SPDs and GDT should be installed by licensed professionals, outside the building or dwelling they are protecting.

Surge protectors

A secondary line of defence is a surge protector - a power board which contains a main power and in some cases a telecommunications supply protection. This is a device which can be plugged directly into a power point to provide protection to electronic and telecommunications equipment. Surge protectors are particularly effective against low voltage surges from causes other than a direct lightning strike. To achieve best protection for equipment, all interconnected devices in the household or office must be connected to surge protectors and not connected to either the power or communication grid through another channel.

Surge protectors work by diverting excess current - in a surge situation - to the earth or ground circuit, thereby only allowing a safe amount of current to reach appliancesvi. The system isn't impossible to defeat, just as the sluice gates on a dam can be overwhelmed by a catastrophic deluge of water, so a surge protector can be overwhelmed by a high voltage, high current flow to it. Still, for a modest outlay, surge protectors offer a good defence against surges, particularly the recurrent, low voltage variety which are capable of damaging equipment over time through repeated exposure.

iHalliday, C. and Urquhart, D. Voltage and Equipment Standard Misalignment, viewed 24 May 2014,

iiTasmanian Government Energy Ombudsman, Frequently asked questions, viewed 24 May 2014,

iiiEnergy and Water Ombudsman - Victoria, Customer FAQs, viewed 24 May 2014,

ivTelstra, Lightning surges naturally occur, viewed 24 May 2014,

vNASA Science, 1999, Human Voltage, What happens when people and lightning converge, viewed 24 May 2014,

viChoice Magazine, 2009, Surge protectors how to avoid the shocking truth, viewed 20 May 2014,