Alert Electric shock from thread cutting machine This alert warns sprinkler fitters, plumbers and other workers of the risk of electric shock when using portable electric thread cutting machines if the machines are not properly maintained. October 2008 Summary This Alert is a warning about the risk of electric shock to workers using portable electric thread cutting machines that are not properly maintained. Background Recently a sprinkler fitter, while supporting the loose end of a pipe being machined, received an electric shock from a portable thread cutting machine. The shock occurred when he also made contact with the ground with his hand. The electric motor had short circuited to the machine’s metal frame. The likely cause of the short circuit was the failure of the insulation coating on the motor windings due to the build-up of carbon dust and other contaminants within the winding’s coils. Carbon dust is generated as the motor’s brushes wear down. Other contaminants can be drawn into the windings through the motor’s cooling system. These include metal fillings, dust and thread cutting compound or oil. regime may have to be more stringent than that for other electrical equipment; intervals between electrical testing should be based on a risk assessment. Insulation resistance readings should be documented to allow for easy detection of deterioration of the insulation before electrical failure. Service and maintenance: • the thread cutting machine must be maintained and serviced according to the manufacturer’s operating instructions • regularly clean the thread cutter to control the build-up of oil, dust, hemp and metal fillings • daily inspections by the operator of the machine prior to use. Further information For further information on service requirements for specific electric thread cutting machines: • consult the manufacturer’s operators manual for the model • the manufacturer or their agent, or • an approved service centre. General information on plant maintenance can be found in WorkSafe Victoria’s Guidance Note - Maintaining plant in safe working order (2005) Copies of this and other publications can be downloaded from WorkSafe’s website at: worksafe.vic.gov.au Note: This Alert has been prepared using the best information available to WorkSafe Victoria. Any information about legislative obligations or responsibilities included in this material is only applicable to the circumstances described in the material. You should always check the legislation referred to in this material and make your own judgement about what action you may need to take to ensure you have complied with the law. Accordingly, WorkSafe Victoria extends no warranties as to the suitability of the information for your specific circumstances. Recommendations Protection against electric shock: • use only socket outlets protected by a Residual Current Device (RCD) • where you cannot confirm a socket outlet is protected by an RCD, use a portable RCD • regularly test thread-cutting machines for electrical insulation resistance and earthing continuity. The testing Contact Details Call us on: 1800 136 089 Email us at: firstname.lastname@example.org For more information on occupational health and safety, go to WorkSafe’s website: www.worksafe.vic.gov.au ! WorkSafe Victoria is a trading name of the Victorian WorkCover Authority.
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