News & Views
25th July 2019
Submersible Water Pump Safety Hazards
Identification of possible “electrical shock” hazard with Evaporative Air Conditioner submersible pumps.
During a summer start up inspection of a roof mounted Braemar evaporative air conditioner unit, a technician was checking for foreign material that may be blocking the inlet of the water pump when he received an electric shock after placing his hand into the water tray.
How did it happen?
- The sealed submersible water pump developed an internal earthing fault, causing electrical current to travel through the pump impeller shaft, energizing the surrounding water.
- The internal fault in the windings of the pump motor did not prevent the pump from operating or to trip the circuit breaker as it had not earthed out.
Immediate actions taken:
- The unit was immediately isolated and tagged out of service.
- The faulty submersible water pump was removed from the unit for testing.
- Bench testing identified an internal broken earth wire that was not detected during the initial startup inspection.
Contractor actions required:
- Contractors and Service staff are to ensure the unit is isolated and tagged out, prior to works commencing.
- Technical Data Sheet ME03 has been updated to include earth continuity and insulation testing of the air conditioning units.
For further information or assistance, contact NECA SA/NT HSEQ Manager, Ben Simpson on (08) 8272 2966 or alternatively you can download the following documents from DPTI: