What would be the result of simply applying a simple PAT routine to the scenario i.e. an appliance with double pole supply relays or similar ‘normally open’ switched circuits?
As indicated in ‘Diagram A’ a simple PAT ‘insulation’ test would essentially only test wiring and components up to the ‘open circuit’ relays and/or switches and if there were no problems up to that point then the appliance would be labelled ‘Passed’. However, as can be seen the items beyond the relays would not have been subjected to the ‘insulation’ test.
What could result if the above occurred?
Firstly lets assume that the components beyond the relays were unknowingly OK i.e. above the required minimum insulation level then essentially there would be no problem with labelling the item as passing the applied safety test. However, this scenario is reliant on luck and not fact. In reality there are many reasons that wiring and/or components within appliances may have degradation (a breaking down) of their insulation. If an EEESafe Registered person was doing their job properly, they would be able to make informed deacons about replacing suspect components, and save costs to themselves and increase durability for the customers. In relation to the washing machine scenarios in Diagrams A & B the two most likely items for lower than acceptable insulation are the heating element and main motor and these are also common items across a range of such major appliances.
What could be the result of having low insulation of items not tested?
Like all accidents and incidents things are rarely all that simple and the result if any bad or good are more often than not dependant on a series of apparently diverse factors coming together. In this scenario if the appliance was passed as ‘Safe’ and was correctly installed into a premises which had the correct electrical supply criteria depending on the severity of the insulation breakdown the appliance may work for sometime before failing by operation of the premises protective fuse, MCB or tripping an RCD (Residual Current Device ) or similar protective device. Annoying for the customers and not instilling confidence in the suppliers of their product either.
However, the installation of appliances is in itself often not carried out to a suitable standard as essentially none exists. In the case of washing machines (and similar appliances) it is often a case of – connect fill and drain hoses – plug it in – fill and empty the appliance and leave. In many instance it does not even go that far.
Editors Note – It is worth noting that EEESafe Registered Technicians are required to ensure Appliances are installed correctly and are not part of a Recall, and if the customer wishes can add them to the EEESafe Appliance Safety Register for free. This provides a free alert service to notify the owner, when and if their appliance becomes subject to a new Fire Risk. Our new Register will shortly be launched, which can be found HERE.