30 October 2009

Electrical hazards from roof installation

Earlier this month, a young roof insulation installer was killed when a a staple used to fix aluminium reflective insulation pierced an electrical cable . Another person helping with the work suffered burns and electrical shock. At another installation site in Brisbane, the homeowner got zapped when he leaned against a metal awning on the back deck of his house after a foil reflective insulation was installed . An electrician detected a 240-volt charge running through the insulation to sarking in the roof and walls and the roof gutters, awnings and poles, all because the foil insulation was stapled into a power cable that was switched off at the time.

The federal government's Home Insulation Program  offers ceiling insulation worth up to $1,600 to owner-occupiers, landlords and tenants. [Update: The home insulation rebate has now been slashed to $1,200]

 [Update: This scheme has now been abandoned effective 19 February 2010] If you have had your roof insulated under this scheme, it is best to get it inspected to stay safe.

The subsidies have boosted the amount of roof insulation installed and Australia is moving towards the government's vision of having Energy Efficient Homes. However, the high demand has also attracted a number of inexperience installers to the industry, and their shoddy work is putting homes and lives at risk. Inadvertently, the program seems to be contributing to an alarming spike in roof space fires and electrical risks. Homeowners should be aware of potential electrical hazards that may be caused by unsafe roof insulation and know the ways to protect yourself from these dangers.

Fire Risk from roof insulation

  • Insulation should never be too close to downlights and their transformers, electrical cables or exhaust fans. Though most insulation is heat-resistant to some extent it can still ignite if it directly covers electrical cables or devices and is exposed to the heat generated for long periods of time
  • Minimum clearance required is 50mm around incandescent lamps or 100mm if located next to structural timber, and 200mm for halogen lamps
  • Downlight guards or other physical fire-resistant barriers should be installed before the insulation is put in [Update: Covers on downlights are now mandatory]
  • Blow-in or loose-fill insulation should be secured properly (usually by spraying an adhesive solution) to prevent movement. Else this can jam blades of an exhaust fan, for e.g., and cause overheating
  • A roof fire is not usually detected by a smoke alarm since the smoke is above the alarm. Homeowners are often unaware of the fire until the damage has been done, and embers fall through air-conditioning ducts or the roof collapses. This makes prevention of any potential fire risk even more important

Electrical shock risk from roof insulation

  • This specifically applies to conductive type of roof insulation such as aluminium foil reflective insulation [Update: Government's new safety guidelines include a ban on the use of metal fasteners on foil insulation]
  • Check that the insulator takes adequate care when installing near electrical equipment including cables, light fittings and ceiling fans, etc

Choose a registered roof insulation installer and licensed electrician

  • Select your installer only from the government provided Installer Provider Register  
  • If in doubt or worried about your roof insulation installation, arrange for an inspection by a licensed electrical contractor

Geoff is a registered electrician with over 20 years experience in the industry. He is also licensed to provide data and voice services. Baishakhi is an MBA and looks after the "business" side of Epping Electrical. Read about Epping Electrical here.

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