Why Three Prongs? (1996)
&gt; Before you &quot;grounded&quot; your system, the AC voltage in general acted pretty safe for your customers. The only way they could get a shock was if they touched both wires at the same time. This was a fairly rare occurrence. One single wire acted as if it was &quot;safe,&quot; and it did not deliver shocks.<p>I&#x27;m confused by the assertion that you could not get a shock from a single wire in an ungrounded system.  If there is 120V AC between the two wires, doesn&#x27;t this mean that there has to be at least 60V AC potential between at least one of the wires and earth ground?  Is he depending on the &quot;halved&quot; voltage for safety, or depending on having an intact circuit so the other connected wire is always &quot;better&quot; than an earth ground, or is he right in some way that I&#x27;m not seeing?