Electronic – Double isolation with earthing symbol inside on power supply

groundingpower supply

I was looking at my laptop's power supply and i noticed this symbol:
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To me totally looks like a "double isolation class 2" IEC 61140 combined with the IEC 60417 – 5018 symbol (Functional earthing; functional grounding), but does such thing exists in any standard? I couldn't find it in IEC 60417.

The negative output of the power supply is connected through a 10kohm resistance to the earth pin of the mains plug (or at least this is what i can measure from the ouside).

  • Isn't this breaing the double isolation condition?
  • Is the earthing there only for reference?
    If that's the case, why bother with the 10k resistor?

Best Answer

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This Class 2 is the symbol for Double Insulation with no earth wire.

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IEC 60417 Class-II-equipment-with-functional-earthing;-Class-II-equipment-with-functional-grounding-(US) Reference No : 6092 Registration date : 2013-03-30 Status : Active

Referenced in :

IEC 60065    
IEC 60950-1    
IEC 62368-1