Equipotential earthing study: equipotential wiring is unnecessary.
This study was undertaken to determine the ongoing need for Equipotential (EP) earthing as required in AS/NZS 3003, section 4.4.2. A total of 2279 earth points were tested in four clinical institutions in Body Protected areas (as defined in AS/NZS 3003). Each earth point was tested for potentials existing in the earthing in order to assess whether any potentials exceeded the 100 mV requirement of AS/NZS 3003 for EP earthing. The voltage measured was 1.21 mV +/- 3.59 mV, (mean +/- standard deviation (SD)), with a of 99 % confidence interval between 1.0 mV and 1.4 mV. This study suggests that the requirements for EP earthing in section 4.4.2 of AS/NZS 3003 are unnecessary. It is further suggested that Standards Australia review these requirements with the view of withdrawing them from the Standard.
Foong
K Pui-tse
KP
Graduate School of Biomedical Engineering, University of New South Wales, Sydney, Australia. kathryn.foong@gmail.com
Watson
A
A
Avolio
A
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D006801:Humans; D001315:Australia; D004556:Electric Injuries / Q000517:prevention & control; D004559:Electric Wiring / Q000592:standards; D004864:Equipment and Supplies / Q000592:standards; D004869:Equipment Safety / Q000592:standards; D017408:Guidelines as Topic; D012015:Reference Standards; D018570:Risk Assessment / Q000592:standards; D017751:Safety Management / Q000592:standards