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SILICON SILIC 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 Mauro Grassi, B.Sc. (Hons), Ph.D Nicholas Vinen 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 is 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: $94.50 per year in Australia. For overseas rates, see the order form 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 The Federal Government’s insulation scheme is a tragedy Back when the Federal Government’s roof insulation scheme was first mooted I had some misgivings about whether taxpayer funds should be spent in this way but I let it pass. After all, I have similar misgivings whenever any government announces any scheme to “fix” a problem, especially when it involves direct subsidies to particular companies or to selected parts of the community. Having said that, I don’t think anyone could have imagined how bad the roofing insulation scheme would turn out to be. Last year I saw the press releases put out by NECA (National Electrical & Communications Association) and other relevant bodies, drawing attention to the safety risks but again, I did not conceive how crazy it would become. For example, I did not think that anyone would be silly enough to use aluminium foil insulation laid over ceiling joists and inevitably, over electrical wiring. Nor did I dream that such foil insulation would be installed using staple guns – the risk of shock and electrocution just beggars belief! But it got worse – much worse! We now know about the fire risk. At the time of writing, there have been more than 100 house fires where the installation of insulation is suspected to be the main cause. However, while halogen light fittings and their transformers have often been implicated, that is not the whole story. In fact, it could be that electrical wiring which originally was quite safe is now rendered dangerous because it can now run much hotter. People do not realise that the Australian wiring standards (AS:NZS 3000) set the amount of current that can pass through power circuits on the basis that the wiring is sitting in free-air, ie, well-ventilated. Furthermore, much of this roofing insulation has been installed in homes which are quite old. Often these houses have sub-standard wiring where the cabling uses cotton-covered rubber or vulcanised rubber insulation. This stuff is a fire hazard anyway but will be more so if it has been disturbed by people moving about in the roof space, installing insulation! And now that such old wiring is covered by insulation, it is more likely to fail, even if it hasn’t been disturbed. Even if none of these problems were in existence, it seems silly to install any form of insulation in the roof space so that much of the electrical wiring is concealed. It means that it becomes difficult to do any repairs in future. So what to do now? The Federal Government has now announced that it will remove aluminium foil insulation from all homes or failing that, it will have RCD safety switches installed to combat the risk of electrocution. Well, yet again, the Government simply doesn’t realise the full extent of the problem. NECA has just released a press release saying that safety switches are not the solution. Indeed, they are correct although they haven’t said why. In fact, RCDs can only protect the house wiring which is downside of the meter box. They cannot protect against the electrocution risk from the main 230VAC feed cable coming in from the street. It is also safe to say that you would need a qualified electrician to inspect the roof space and identify the main feed cable – that is just not going to happen. Furthermore, RCDs cannot be used to protect wiring which feeds hot water systems so you potentially have a number of electrical circuits in the roof which cannot be protected. Even if they are installed, RCDs will not mitigate the risk of fire in sub-standard wiring. With that in mind, there is no solution other than removing all foil insulation installed under the Government’s scheme. But that will not prevent the occurrence of fires because insulation batts have been laid over old wiring, halogen lamps or their transformers. And nor can any number of roof inspections totally remove that risk. There will certainly be more fires – that is unavoidable. Ultimately, the legal fraternity will have a field day. It seems to me that the Federal Government’s insulation scheme will go down in history as one of the worst ever government initiatives since Federation. Leo Simpson siliconchip.com.au