With electrical appliances there is obviously a risk of shock involved should anything go wrong with the appliance.  The effects of electric shock are unpredictable and can lead to vey serious injury but there are also risks from burns.  Burn injuries can occur from accidentally short circuiting an appliance.  And, although pat testing, is usually carried out by reputable and well trained engineers there could still be occasions when electric shock occurs so risk assessments should be carried out before any testing is done.  Perhaps the most important risk assessment is whether the appliance can be tested whilst ‘dead’, ie, whilst disconnected from the mains supply.