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SILICON CHIP www.siliconchip.com.au Publisher & Editor-in-Chief Leo Simpson, B.Bus., FAICD Production Manager Greg Swain, B.Sc.(Hons.) Technical Editor John Clarke, B.E.(Elec.) Technical Staff Ross Tester Jim Rowe, B.A., B.Sc, VK2ZLO Mauro Grassi, B.Sc.(Hons.) Photography Ross Tester Reader Services Ann Morris Advertising Enquiries Glyn Smith Phone (02) 9939 3295 Mobile 0431 792 293 glyn<at>siliconchip.com.au Regular Contributors Brendan Akhurst Rodney Champness, VK3UG Mike Sheriff, B.Sc, VK2YFK Stan Swan SILICON CHIP is published 12 times a year by Silicon Chip Publications Pty Ltd. ACN 003 205 490. ABN 49 003 205 490 All material copyright ©. No part of this publication may be reproduced without the written consent of the publisher. Printing: Hannanprint, Noble Park, Victoria. Distribution: Network Distribution Company. Subscription rates: $89.50 per year in Australia. For overseas rates, see the subscription page in this issue. Editorial office: Unit 1, 234 Harbord Rd, Brookvale, NSW 2100. Postal address: PO Box 139, Collaroy Beach, NSW 2097. Phone (02) 9939 3295. Fax (02) 9939 2648. E-mail: silicon<at>siliconchip.com.au ISSN 1030-2662 * Recommended and maximum price only. 2  Silicon Chip Publisher’s Letter Electrical wiring in older houses can be dangerous As might be expected, our recent articles on do-it-yourself wiring have generated quite a deal of comment, some of it very useful. For example, following our story on Light Switches in the July 2008 issue, a reader rang to point out that if anyone is changing a light bulb or doing anything else with a light fitting, they should be aware that the light socket can easily have power on it, even when the light switch is turned off. This is true and is particularly the case if the “loop” terminal has been used to terminate an Active wire. People should also be aware that some Edison sockets are inherently unsafe if they expose any of the metalwork which is connected to the lamp itself. This is because the outer screw thread of the lamp is part of the lamp circuit. In fact, in my opinion, 240VAC Edison lamps and fittings should never have been approved for use in Australia. So if you want to safely work on a light fitting or change an Edison screw light bulb, perhaps you should kill the power at the switchboard. So we do acknowledge that DIY wiring is not without its hazards. But provided people use common sense and the information available on the relevant New Zealand government websites, it can be done safely and correctly. However, Australian electrical supply authorities continue to the push the line that DIY wiring is “rooly rooly” dangerous. I am indebted to a reader who sent me a 4-page liftout inserted by Energex into the Brisbane Sunday Mail on June 8, 2008. In it they provide some perfectly innocuous information about using electricity safely, not using appliances with frayed power cords or overloading power points and so on. No problems there. But they go on to warn about the dangers of do-it-yourself wiring and state that “Hundreds of Queenslanders have been killed as a result of unauthorised or unsafe electrical work being carried out around the home”. Well, really? Over what period? Since Federation? This statement is patently untrue. Sure, hundreds of people may have been killed over a period of many years due to electrocution but the vast majority of those were nothing to do with wiring in the home, unauthorised or not. Our article in the June 2008 issue quoted from ABS figures and these show that there are typically three electrical fatalities in Queensland in a year. Only three? Yes. So why does Energex and other Australian electrical supply authorities continue to spend huge amounts of money advertising the evils of DIY wiring? We can only surmise that it is to stay on the good side of the electrical trades unions. Even then we cannot understand it, because most electricians would admit that they have more work than they can handle. In fact, it could be argued that if the electrical supply authorities really want to promote electrical safety, they should be highlighting the dangers of decrepit wiring in older homes, particularly those with cotton-covered or vulcanised rubber insulation. As fire departments and insurance companies can attest, this old wiring is a real fire hazard. In fact, if your home is 50 years old or more, the wiring is almost certain to be unsafe or in need of upgrading. Furthermore, if the supply authorities have so much money to spare, perhaps they should use it as subsidies for those people on lower incomes who cannot afford the cost of a full rewiring job. Leo Simpson siliconchip.com.au