Why is one lightbulb in a string illuminated?





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Photo of only one light illuminated



I noticed that in various strings of lights only one was illuminated. It seems implausible that all but one out of several hundred blew. What caused this and why did this particular light turn on?










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  • 1




    $begingroup$
    I think there is too less information to answer this question without speculation, and there is probably neither no way to validate an answer in order to accept it.
    $endgroup$
    – Huisman
    8 hours ago






  • 1




    $begingroup$
    Never seen serial streetlights on cables from street-corners before. But if there enough mutual coupling to power 1 bulb out of say 30 in series. The bulb with the fastest warm-up time draws all the induced voltage ( e.g. 240/30) due to 10:1 PTC effects
    $endgroup$
    – Sunnyskyguy EE75
    7 hours ago










  • $begingroup$
    Looks a lovely park not far from the Welsh coast
    $endgroup$
    – Sunnyskyguy EE75
    7 hours ago










  • $begingroup$
    How about this: The lamps are on a photocell-switched circuit, but one lamp is lit constantly to indicate that the circuit is powered. It's not dark enough to trigger to photocell switch.
    $endgroup$
    – Hot Licks
    4 hours ago


















5












$begingroup$


Photo of only one light illuminated



I noticed that in various strings of lights only one was illuminated. It seems implausible that all but one out of several hundred blew. What caused this and why did this particular light turn on?










share|improve this question







New contributor




dothyphendot is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.







$endgroup$








  • 1




    $begingroup$
    I think there is too less information to answer this question without speculation, and there is probably neither no way to validate an answer in order to accept it.
    $endgroup$
    – Huisman
    8 hours ago






  • 1




    $begingroup$
    Never seen serial streetlights on cables from street-corners before. But if there enough mutual coupling to power 1 bulb out of say 30 in series. The bulb with the fastest warm-up time draws all the induced voltage ( e.g. 240/30) due to 10:1 PTC effects
    $endgroup$
    – Sunnyskyguy EE75
    7 hours ago










  • $begingroup$
    Looks a lovely park not far from the Welsh coast
    $endgroup$
    – Sunnyskyguy EE75
    7 hours ago










  • $begingroup$
    How about this: The lamps are on a photocell-switched circuit, but one lamp is lit constantly to indicate that the circuit is powered. It's not dark enough to trigger to photocell switch.
    $endgroup$
    – Hot Licks
    4 hours ago














5












5








5


2



$begingroup$


Photo of only one light illuminated



I noticed that in various strings of lights only one was illuminated. It seems implausible that all but one out of several hundred blew. What caused this and why did this particular light turn on?










share|improve this question







New contributor




dothyphendot is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.







$endgroup$




Photo of only one light illuminated



I noticed that in various strings of lights only one was illuminated. It seems implausible that all but one out of several hundred blew. What caused this and why did this particular light turn on?







parallel lighting






share|improve this question







New contributor




dothyphendot is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.











share|improve this question







New contributor




dothyphendot is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
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share|improve this question




share|improve this question






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asked 9 hours ago









dothyphendotdothyphendot

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New contributor





dothyphendot is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.






dothyphendot is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.








  • 1




    $begingroup$
    I think there is too less information to answer this question without speculation, and there is probably neither no way to validate an answer in order to accept it.
    $endgroup$
    – Huisman
    8 hours ago






  • 1




    $begingroup$
    Never seen serial streetlights on cables from street-corners before. But if there enough mutual coupling to power 1 bulb out of say 30 in series. The bulb with the fastest warm-up time draws all the induced voltage ( e.g. 240/30) due to 10:1 PTC effects
    $endgroup$
    – Sunnyskyguy EE75
    7 hours ago










  • $begingroup$
    Looks a lovely park not far from the Welsh coast
    $endgroup$
    – Sunnyskyguy EE75
    7 hours ago










  • $begingroup$
    How about this: The lamps are on a photocell-switched circuit, but one lamp is lit constantly to indicate that the circuit is powered. It's not dark enough to trigger to photocell switch.
    $endgroup$
    – Hot Licks
    4 hours ago














  • 1




    $begingroup$
    I think there is too less information to answer this question without speculation, and there is probably neither no way to validate an answer in order to accept it.
    $endgroup$
    – Huisman
    8 hours ago






  • 1




    $begingroup$
    Never seen serial streetlights on cables from street-corners before. But if there enough mutual coupling to power 1 bulb out of say 30 in series. The bulb with the fastest warm-up time draws all the induced voltage ( e.g. 240/30) due to 10:1 PTC effects
    $endgroup$
    – Sunnyskyguy EE75
    7 hours ago










  • $begingroup$
    Looks a lovely park not far from the Welsh coast
    $endgroup$
    – Sunnyskyguy EE75
    7 hours ago










  • $begingroup$
    How about this: The lamps are on a photocell-switched circuit, but one lamp is lit constantly to indicate that the circuit is powered. It's not dark enough to trigger to photocell switch.
    $endgroup$
    – Hot Licks
    4 hours ago








1




1




$begingroup$
I think there is too less information to answer this question without speculation, and there is probably neither no way to validate an answer in order to accept it.
$endgroup$
– Huisman
8 hours ago




$begingroup$
I think there is too less information to answer this question without speculation, and there is probably neither no way to validate an answer in order to accept it.
$endgroup$
– Huisman
8 hours ago




1




1




$begingroup$
Never seen serial streetlights on cables from street-corners before. But if there enough mutual coupling to power 1 bulb out of say 30 in series. The bulb with the fastest warm-up time draws all the induced voltage ( e.g. 240/30) due to 10:1 PTC effects
$endgroup$
– Sunnyskyguy EE75
7 hours ago




$begingroup$
Never seen serial streetlights on cables from street-corners before. But if there enough mutual coupling to power 1 bulb out of say 30 in series. The bulb with the fastest warm-up time draws all the induced voltage ( e.g. 240/30) due to 10:1 PTC effects
$endgroup$
– Sunnyskyguy EE75
7 hours ago












$begingroup$
Looks a lovely park not far from the Welsh coast
$endgroup$
– Sunnyskyguy EE75
7 hours ago




$begingroup$
Looks a lovely park not far from the Welsh coast
$endgroup$
– Sunnyskyguy EE75
7 hours ago












$begingroup$
How about this: The lamps are on a photocell-switched circuit, but one lamp is lit constantly to indicate that the circuit is powered. It's not dark enough to trigger to photocell switch.
$endgroup$
– Hot Licks
4 hours ago




$begingroup$
How about this: The lamps are on a photocell-switched circuit, but one lamp is lit constantly to indicate that the circuit is powered. It's not dark enough to trigger to photocell switch.
$endgroup$
– Hot Licks
4 hours ago










2 Answers
2






active

oldest

votes


















4












$begingroup$

enter image description here



Figure 1. The intriguing light bulb has caught the attention of Smokey the Bear too.



There can only be a few possibilities:




  • The lamps are spread across several phases or split phases, the other phases are off and all but this lamp has blown. This is very unlikely.

  • Some joker has installed a battery powered lamp. This too seems unlikely.



"When you have eliminated the impossible, whatever remains, however improbable, must be the truth." Sherlock Holmes.





  • The impossible has happened and all have blown but one. This could happen with an overvoltage - by lightning, for example. Some combination of poor contact, tough filament, arcing in another lamp (which would limit the voltage), etc., may be enough to let it survive.




Another possibility is that the power is on and that each bulb has its own light sensor (like some streetlights) and this one is the first to switch on. Again, unlikely.






share|improve this answer











$endgroup$













  • $begingroup$
    I'd go with the battery powered hypothesis, there are available lamps that include a battery back-up
    $endgroup$
    – Jasen
    8 hours ago










  • $begingroup$
    Are these lamps connected in series or parallel? Or several series strings in parallel?
    $endgroup$
    – Toor
    8 hours ago










  • $begingroup$
    looks like parallel festoon fittings to me
    $endgroup$
    – Jasen
    8 hours ago






  • 1




    $begingroup$
    Then the o/v has my vote. Someone may have fitted a single 275V (very likely 260V) globe as a spare. We had these in Western Australia for a long time and they lasted forever back when we were 250V and the rest of the country 240V. (almost always higher in both cases).
    $endgroup$
    – mckenzm
    5 hours ago





















2












$begingroup$

I'd go with the implausible explanation. All the bulbs are blown except the one.



Most festoon lights use a screw-in socket so all the lights are in parallel:



enter image description here



I'd suggest that the string was perhaps hit by a truck (or a surge) and a bunch of the lights broke.






share|improve this answer









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    2 Answers
    2






    active

    oldest

    votes








    2 Answers
    2






    active

    oldest

    votes









    active

    oldest

    votes






    active

    oldest

    votes









    4












    $begingroup$

    enter image description here



    Figure 1. The intriguing light bulb has caught the attention of Smokey the Bear too.



    There can only be a few possibilities:




    • The lamps are spread across several phases or split phases, the other phases are off and all but this lamp has blown. This is very unlikely.

    • Some joker has installed a battery powered lamp. This too seems unlikely.



    "When you have eliminated the impossible, whatever remains, however improbable, must be the truth." Sherlock Holmes.





    • The impossible has happened and all have blown but one. This could happen with an overvoltage - by lightning, for example. Some combination of poor contact, tough filament, arcing in another lamp (which would limit the voltage), etc., may be enough to let it survive.




    Another possibility is that the power is on and that each bulb has its own light sensor (like some streetlights) and this one is the first to switch on. Again, unlikely.






    share|improve this answer











    $endgroup$













    • $begingroup$
      I'd go with the battery powered hypothesis, there are available lamps that include a battery back-up
      $endgroup$
      – Jasen
      8 hours ago










    • $begingroup$
      Are these lamps connected in series or parallel? Or several series strings in parallel?
      $endgroup$
      – Toor
      8 hours ago










    • $begingroup$
      looks like parallel festoon fittings to me
      $endgroup$
      – Jasen
      8 hours ago






    • 1




      $begingroup$
      Then the o/v has my vote. Someone may have fitted a single 275V (very likely 260V) globe as a spare. We had these in Western Australia for a long time and they lasted forever back when we were 250V and the rest of the country 240V. (almost always higher in both cases).
      $endgroup$
      – mckenzm
      5 hours ago


















    4












    $begingroup$

    enter image description here



    Figure 1. The intriguing light bulb has caught the attention of Smokey the Bear too.



    There can only be a few possibilities:




    • The lamps are spread across several phases or split phases, the other phases are off and all but this lamp has blown. This is very unlikely.

    • Some joker has installed a battery powered lamp. This too seems unlikely.



    "When you have eliminated the impossible, whatever remains, however improbable, must be the truth." Sherlock Holmes.





    • The impossible has happened and all have blown but one. This could happen with an overvoltage - by lightning, for example. Some combination of poor contact, tough filament, arcing in another lamp (which would limit the voltage), etc., may be enough to let it survive.




    Another possibility is that the power is on and that each bulb has its own light sensor (like some streetlights) and this one is the first to switch on. Again, unlikely.






    share|improve this answer











    $endgroup$













    • $begingroup$
      I'd go with the battery powered hypothesis, there are available lamps that include a battery back-up
      $endgroup$
      – Jasen
      8 hours ago










    • $begingroup$
      Are these lamps connected in series or parallel? Or several series strings in parallel?
      $endgroup$
      – Toor
      8 hours ago










    • $begingroup$
      looks like parallel festoon fittings to me
      $endgroup$
      – Jasen
      8 hours ago






    • 1




      $begingroup$
      Then the o/v has my vote. Someone may have fitted a single 275V (very likely 260V) globe as a spare. We had these in Western Australia for a long time and they lasted forever back when we were 250V and the rest of the country 240V. (almost always higher in both cases).
      $endgroup$
      – mckenzm
      5 hours ago
















    4












    4








    4





    $begingroup$

    enter image description here



    Figure 1. The intriguing light bulb has caught the attention of Smokey the Bear too.



    There can only be a few possibilities:




    • The lamps are spread across several phases or split phases, the other phases are off and all but this lamp has blown. This is very unlikely.

    • Some joker has installed a battery powered lamp. This too seems unlikely.



    "When you have eliminated the impossible, whatever remains, however improbable, must be the truth." Sherlock Holmes.





    • The impossible has happened and all have blown but one. This could happen with an overvoltage - by lightning, for example. Some combination of poor contact, tough filament, arcing in another lamp (which would limit the voltage), etc., may be enough to let it survive.




    Another possibility is that the power is on and that each bulb has its own light sensor (like some streetlights) and this one is the first to switch on. Again, unlikely.






    share|improve this answer











    $endgroup$



    enter image description here



    Figure 1. The intriguing light bulb has caught the attention of Smokey the Bear too.



    There can only be a few possibilities:




    • The lamps are spread across several phases or split phases, the other phases are off and all but this lamp has blown. This is very unlikely.

    • Some joker has installed a battery powered lamp. This too seems unlikely.



    "When you have eliminated the impossible, whatever remains, however improbable, must be the truth." Sherlock Holmes.





    • The impossible has happened and all have blown but one. This could happen with an overvoltage - by lightning, for example. Some combination of poor contact, tough filament, arcing in another lamp (which would limit the voltage), etc., may be enough to let it survive.




    Another possibility is that the power is on and that each bulb has its own light sensor (like some streetlights) and this one is the first to switch on. Again, unlikely.







    share|improve this answer














    share|improve this answer



    share|improve this answer








    edited 8 hours ago

























    answered 8 hours ago









    TransistorTransistor

    89.4k786192




    89.4k786192












    • $begingroup$
      I'd go with the battery powered hypothesis, there are available lamps that include a battery back-up
      $endgroup$
      – Jasen
      8 hours ago










    • $begingroup$
      Are these lamps connected in series or parallel? Or several series strings in parallel?
      $endgroup$
      – Toor
      8 hours ago










    • $begingroup$
      looks like parallel festoon fittings to me
      $endgroup$
      – Jasen
      8 hours ago






    • 1




      $begingroup$
      Then the o/v has my vote. Someone may have fitted a single 275V (very likely 260V) globe as a spare. We had these in Western Australia for a long time and they lasted forever back when we were 250V and the rest of the country 240V. (almost always higher in both cases).
      $endgroup$
      – mckenzm
      5 hours ago




















    • $begingroup$
      I'd go with the battery powered hypothesis, there are available lamps that include a battery back-up
      $endgroup$
      – Jasen
      8 hours ago










    • $begingroup$
      Are these lamps connected in series or parallel? Or several series strings in parallel?
      $endgroup$
      – Toor
      8 hours ago










    • $begingroup$
      looks like parallel festoon fittings to me
      $endgroup$
      – Jasen
      8 hours ago






    • 1




      $begingroup$
      Then the o/v has my vote. Someone may have fitted a single 275V (very likely 260V) globe as a spare. We had these in Western Australia for a long time and they lasted forever back when we were 250V and the rest of the country 240V. (almost always higher in both cases).
      $endgroup$
      – mckenzm
      5 hours ago


















    $begingroup$
    I'd go with the battery powered hypothesis, there are available lamps that include a battery back-up
    $endgroup$
    – Jasen
    8 hours ago




    $begingroup$
    I'd go with the battery powered hypothesis, there are available lamps that include a battery back-up
    $endgroup$
    – Jasen
    8 hours ago












    $begingroup$
    Are these lamps connected in series or parallel? Or several series strings in parallel?
    $endgroup$
    – Toor
    8 hours ago




    $begingroup$
    Are these lamps connected in series or parallel? Or several series strings in parallel?
    $endgroup$
    – Toor
    8 hours ago












    $begingroup$
    looks like parallel festoon fittings to me
    $endgroup$
    – Jasen
    8 hours ago




    $begingroup$
    looks like parallel festoon fittings to me
    $endgroup$
    – Jasen
    8 hours ago




    1




    1




    $begingroup$
    Then the o/v has my vote. Someone may have fitted a single 275V (very likely 260V) globe as a spare. We had these in Western Australia for a long time and they lasted forever back when we were 250V and the rest of the country 240V. (almost always higher in both cases).
    $endgroup$
    – mckenzm
    5 hours ago






    $begingroup$
    Then the o/v has my vote. Someone may have fitted a single 275V (very likely 260V) globe as a spare. We had these in Western Australia for a long time and they lasted forever back when we were 250V and the rest of the country 240V. (almost always higher in both cases).
    $endgroup$
    – mckenzm
    5 hours ago















    2












    $begingroup$

    I'd go with the implausible explanation. All the bulbs are blown except the one.



    Most festoon lights use a screw-in socket so all the lights are in parallel:



    enter image description here



    I'd suggest that the string was perhaps hit by a truck (or a surge) and a bunch of the lights broke.






    share|improve this answer









    $endgroup$


















      2












      $begingroup$

      I'd go with the implausible explanation. All the bulbs are blown except the one.



      Most festoon lights use a screw-in socket so all the lights are in parallel:



      enter image description here



      I'd suggest that the string was perhaps hit by a truck (or a surge) and a bunch of the lights broke.






      share|improve this answer









      $endgroup$
















        2












        2








        2





        $begingroup$

        I'd go with the implausible explanation. All the bulbs are blown except the one.



        Most festoon lights use a screw-in socket so all the lights are in parallel:



        enter image description here



        I'd suggest that the string was perhaps hit by a truck (or a surge) and a bunch of the lights broke.






        share|improve this answer









        $endgroup$



        I'd go with the implausible explanation. All the bulbs are blown except the one.



        Most festoon lights use a screw-in socket so all the lights are in parallel:



        enter image description here



        I'd suggest that the string was perhaps hit by a truck (or a surge) and a bunch of the lights broke.







        share|improve this answer












        share|improve this answer



        share|improve this answer










        answered 8 hours ago









        Jack CreaseyJack Creasey

        15.4k2823




        15.4k2823






















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