More information:
Note: ALWAYS test the mains tester on a known live source before use, to determine that its indicator bulb is functioning correctly prior to use.
WARNING: The earthing position of the user largely determines whether the tester bulb will illuminate or not. Failure to illuminate therefore does not provide 100% confirmation that no voltage is present.
 
                         
         
    
    
      
      
        
      
      
        
        
          
        
        
 
    
    
   
    
    
      
      
        
      
      
        
        
          
        
        
 
    
    
      
      
        
      
      
        
        
          
        
        
 
      
    
  