12
Electrical
news
New safety alert for working
with submersible pumps
Following the electrocution death of
a farm worker in January, WorkSafe has
issued a new safety alert to highlight
the risk of electric shock when using or
accessing submersible pumps. The safety
alert is reproduced here with permission
from WorkSafe.
What are submersible pumps?
Submersible pumps are designed to work
while fully submerged in liquid and are regularly
used to pump out pits, storage tanks, flooded
trenches or excavations. They are also used in
wells and dams.
The motor on a submersible pump is attached
directly to the pump body and submerged in the
liquid (see diagram). Many submersible pumps
need to be fully submerged to prevent the pump
motor from overheating and burning out.
The power cable to submersible pumps is a
waterproof rubberised flexible cord. These pumps
are often fitted with a float switch that automatically
turns the pump on and off to maintain the liquid
between two pre-set levels.
Submersible pumps at workplaces are
usually 240 Volt but can be three-phase 415 Volt.
They can be constructed from a variety
of materials including stainless steel, cast
aluminium and plastic.
Risks
Persons handling submersible pumps may be
exposed to electric shock risks due to:
»» deterioration (due to age or reaction to the
liquid) or mechanical damage to the flexible
power cord fitted to the pump
»» deterioration or damage to the plug-top fitted
to the pump’s power cord
»» ingress of water into the electric components
of the pump
»» burning out of the pump’s electric motor
»» failure of part of the pump’s earthing system
»» unlicensed person undertaking
electrical work.
Recommended control measures
As far as possible, employers must provide
and maintain a working environment that is safe
and without risks to the health of its employees.
Employers must also ensure, as far as
reasonably possible, their conduct does not
expose other people to risks to their health
or safety.
The risk of electric shock may be reduced
by ensuring:
»» Electrical safety controls are in place, such as:
›› protecting the pump or the socket-outlet
(powerpoint) that the pump is plugged into
with a fixed 30mA residual current device
(RCD)
›› ensuring that when pumps are plugged into
a socket-outlet, the outlet is suitable for the
location (such as weatherproof type rated
at IP56)
Rope attached to pump handle
for lifting and lowering
Power cable
Handle
Head cover
Motor frame
Discharge outlet
Float switch
Casing
Strainer
Common type of submersible pump with power cord and float
›› maintaining electrical equipment in a
safe working condition, including regular
inspection and maintainance
›› ensuring the pump can be lifted and
lowered out of the liquid without using the
pump’s power cord
›› ensuring electrical work at the workplace
is only undertaken by persons who have
the appropriate electrical licence.
Have safe work systems
Employers should ensure safe systems
of work are in place, such as:
»» providing information, instruction, and training
»» turning off or unplugging and locking-out
the pump before touching the liquid or
equipment, as the pump may be live and only
switched off by the float switch
»» conducting a visual inspection of the lead and
pump for damage prior to reinstalling
or using the pump
»» not using damaged or suspect equipment
»» reporting any electric shocks,
damage or incidents promptly to
the person in management control
so the installation and equipment can
be checked by an electrician
»» supervising the work to the extent
necessary to ensure workers are working
safely and without risks to health.
»» ensuring the pump frequency and voltage
specification are suitable for Victoria’s
supply by checking the labelling on the
pump, with the supplier, or with
an electrician.
For specific electrical safety advice about
the electrical installation at your workplace,
engage a licenced electrician or electrical
inspector.
To get RCDs fitted, contact a licensed
electrician who must issue you a Certificate
of Electrical Safety specifying the work done.