XPost: rec.arts.comics.strips   
   From: mjackson@alumni.caltech.edu   
      
   On 12/29/2025 3:18 PM, Scott Lurndal wrote:   
   > Mark Jackson  writes:   
   >> On 12/28/2025 12:42 PM, Scott Lurndal wrote:   
   >>> Mark Jackson  writes:   
   >>>> On 12/27/2025 1:44 PM, Scott Lurndal wrote:   
   >>>>> Don't blame the electricians if you're shorted (pun   
   >>>>> intended); they're contracted and paid by the builder.   
   >>>>   
   >>>> While doing my thesis research I discovered that the floor   
   >>>> receptacle where I worked, although with a three-pin face, had   
   >>>> no internal connection for the safety ground.   
   >>>   
   >>> If the circuit is run in metal pipe, the conduit itself can act   
   >>> as the grounding conductor[*].   I believe that this was allowed   
   >>> by NEC in the past, so you won't find an explicit grounding   
   >>> conductor in that situation.   
   >>   
   >> The grounding pin receptacle was connected to *nothing*.   
   >   
   > That doesn't necessarily mean that the receptacle wasn't grounded -   
   > iff the above constraints (metal all the way) hold.   The ground pin   
   > in the receptacle socket is connected to the metal ears that are   
   > used to screw the receptacle to the metal handy/outlet box.   
   >   
   >> Had it somhow been grounded the other half of the problem - hot   
   >> and return flipped, for most of the equipment on the island -   
   >> would have instantly tripped the breaker.   
   >   
   > Would it?   The return (neutral/grounded conductor) and ground   
   > (grounding conductor) are only connected at the service entrance   
   > (assuming the installation was correctly done).  Old equipment (e.g.   
   > stoves in pre-grounding conductor days) tied the frame to neutral,   
   > which was a shock hazard if the hot and neutral were flipped but   
   > wouldn't result in an overcurrent device triggering.   
      
   Hypotheticals aside, here are the facts:  the situation came to light   
   when the breaker tripped.  The cause of the breaker tripping was   
   connecting a new, correctly-grounded piece of equipment (including   
   safety ground) to the floating electronics on the island.  The one piece   
   of existing equipment that did not have neutral and hot flipped was the   
   one piece plugged into the floor receptacle with no safety ground -   
   which is why the breaker did not trip before.   
      
   --   
   Mark Jackson - https://mark-jackson.online/   
      Every human society must justify its inequalities.   
                       - Thomas Piketty   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)