From: timothy42bach@gmail.com   
      
   On Thursday, September 15, 2022 at 7:55:46 AM UTC-4, Adrian Caspersz wrote:   
      
   >    
   > LED tubes internally are wired to the supply at one end, the other end    
   > is made as a short circuit - so that the LED tube can be used as a plug    
   > and play for a florescent tube if the starter (and ballast) is also    
   > replaced with a short.    
   >    
   > Please refer to a standard fluorescent wiring diagram to see how this    
   > series wiring works, and then maintain the existing wiring so that the    
   > supply is still externally supplied to both ends in _series_    
   >    
   > (If you have done that, probably wise to scribble a warning with a    
   > permanent pen to remind ye which end of the tube should be fitted to    
   > supply)    
   >    
   > --    
   > Adrian C   
      
   Thanks for the reply.  This is only partially correct though, unless I'm   
   misunderstanding.   
      
   I've been replacing fluorescent tubes in my house and shed for a while now,   
   only a couple to go.  The first several I did were exactly as you say, the LED   
   tubes were single end powered.  This required an unshunted tombstone at one   
   end, with hot and    
   neutral connected to that end, and the tombstone at the other end was just   
   mechanical support with no wiring to it.  This is the way the installation   
   instructions read for all single end LED tubes.  It's also the simplest and   
   easiest to rewire, you    
   usually have enough existing wire length to at least one end.  (yes, at least   
   once my tube didn't light, because I'd put the wrong end in)     
      
   If I understand what you are trying to say, you would use an unshunted   
   tombstone at the powered end, continue the circuit to a shunted tombstone at   
   the other end, then back to the powered end, then to neutral???  I think that   
   would trip the breaker    
   immediately but maybe I'm not understanding.  Remember the ballast is gone   
   with these tubes.  Or you could run wires in parallel, one hot and one neutral   
   to both ends with unshunted tombstones, and it wouldn't matter if you put a   
   single end LED in either    
   direction.  But accidentally putting a double end tube or an old fluorescent   
   in would be a disaster.     
      
   But I've also used the double end LED tubes, where you run hot to one end and   
   neutral to the other, and I tend to think these are safer.  This is how the   
   installation instructions read for the PlugPlay ones I mistakenly bought.  The   
   instructions for this    
   type say either use shunted tombstones or pigtail the wire to both contacts of   
   a shunted one.  I'm not sure why that is necessary, seems like one pin would   
   be enough.     
      
   It seems to me that direct wire tubes would be easier to design and   
   manufacture than PlugPlay, and my evidence is that not all ballasts are   
   compatible.  But I have no idea what extra circuitry is involved, and would be   
   interested if anyone would share.     
      
        
      
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