Safety Alert
Electric shock hazards associated
with excessive sweating whilst using
mains powered tools
The purpose of this Safety Alert is to highlight the hazard of electric shock to workers using mains powered
tools due to excessive sweating with the onset of the build-up.
Background
NT WorkSafe has observed a substantial rise in electric shock reports during the build-up due to sweat
entering power tools whilst they are being operated.
During the build-up temperatures easily reach or exceed 35°C and the humidity levels can rise as high as
90%, excessive sweating is unavoidable during these periods.
Power drills, grinders, welders and tech screw guns are the most common power tools to cause electric
shocks during hot humid build up conditions. Sweat runs over the power tool being used often entering the
trigger and air vents causing surface tracking over the plastic shell.
Welders often receive shocks when sweat soaked gloves and clothing offer a better return path than the metal
being welded, often this occurs due to a failure to maintain effective earthing between materials being welded.
Sweat contains mainly water; it also contains minerals, lactate, and urea. Mineral composition varies with the
individual, an indication of the mineral content is, potassium, calcium, magnesium, zinc, copper, iron,
chromium and nickel. This makes sweat extremely conductive to mains voltage electricity.
The electric shocks received are rarely life threatening, however they do result in substantial lost time due to
the requirement for medical supervision and an ECG (Electrocardiogram) following an electric shock.
Action required
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If possible avoid mains powered tool use during the hottest part of the day, opting instead for air tools
or battery powered tools
The use of residual current devices (RCD’s or Safety Switches) is mandatory on construction sites,
in workshops, and work places. A functional RCD will limit an electric shock to a sub critical level,
however all shocks must still be reported to NT WorkSafe and the victim attend a medical clinic for
medical supervision
The use of isolation transformers can also limit the electric shock risk; however they are heavy and
expensive, for the most part are not used in the construction industry
Welders should consider using Voltage Reduction Devices, and G Clamp earths to minimize
these risks
Power tools causing shocks also need to be isolated and tagged out and examined by a competent
person to ensure they are still fit for use and to be retested and tagged.
Contact details
Call us on: 1800 019 115 or Email us at: ntworksafe@nt.gov.au or visit www.worksafe.nt.gov.au
Disclaimer
This Safety Alert contains safety information following inquires made by NT WorkSafe about an incident or unsafe practice. The information contained in
this Alert does not necessarily include the outcome of NT WorkSafe’s action with respect to an incident. NT WorkSafe does not warrant the information
in this Alert is complete or up-to-date and does not accept any liability for the information in this report or as to its use.
(version 1.0 – 21 August 2013)