View Single Post
  #15   Report Post  
Posted to sci.electronics.repair
Arfa Daily Arfa Daily is offline
external usenet poster
 
Posts: 6,772
Default Christmas Light Puzzler - HELP


wrote in message
...
On Nov 18, 7:26 am, "Arfa Daily" wrote:
"James Sweet" wrote in message

news:KbQ%i.5554$B21.4712@trndny07...





"**THE-RFI-EMI-GUY**" wrote in message
...
Don't try to short out the safety bulb, or you will have a fire. It
is
there to act as a fuse.


As the "shunt" bulbs burn out, the voltage (and current) accross the
remaining bulbs increases thus accelerating failure of remaining
"shunt"
bulbs. Eventually the "safety" bulb in the string blows out. The
solution
is to replace "shunt" bulbs whenever they blow out. Delayed too long,
the
"safety" bulb goes as well.


I would string a new set of lights on the worst branches this year and
replace the tree next year for safety's sake.


2500 lights, thats a lot of lights!


When did this "safety bulb" thing come about? This thread is the first
I've ever seen or heard of it. Is it a European thing or is this here
in
the US? Every string of miniature series lights I've ever seen has all
identical shunted lamps and a fused plug.


I bought very long strings in Walmart a few years back, as house
decoration
lights are VERY expensive here in the UK compared to in the US. As each
'set' is made up of two strings, originally paralleled by the
end-of-string
connectors for use on US 110v line power, it was easy enough over here to
just remove the plugs at one end and series two strings for 230v line
power.
You could then just plug two more 110v strings, one into each 'far-end'
connector, to have two 110v paralleled strings in series with another
two,
across atotal supply of 230v for 2000 lights. Total cost about $16 as I
recall. Over here, that amount of lamps would have cost $200 or more,
equivalent.

Anyways, the point is that these are a three wire circuit, and each new
three wire sub-string, has a replaceable safety fuse lamp at its
beginning,
so there are multiple safety bulbs per fully wired string. So no, it's
not a
European-only thing, as these are US purchased lights. Every year, these
ones drive me up the wall as well. Every year, I think that I've got the
wiring arrangement 'fixed' in my head, then every year, it all seems to
go
wrong. The fact that I have paralleled strings in series, *really*
confuses
the issue, because if one section of one string goes out on one series'd
half, then the voltage no longer divides equally across each paralleled
string, so one half lights up like flashlamp bulbs, whilst the other half
go
as dim as candles ...

Arfa- Hide quoted text -

- Show quoted text -


Arfa,

If you need more lights shipped over there, just send me an email
direct, tell me what you want, and I'd be happy to help you.

And thanks for your response to the post.


Thanks, Bruce. Kind of you to offer. I do get over to the US fairly often
( I will be in Vegas in a few weeks time ) so I usually take the opportunity
to stock up on stuff like this that I can't get back home - like Advil for
instance, or Bengay patches for my dear old mum's arthritic neck. Last time
I was there just before Christmas, I bought another whole set of lights.
They were literally about $5 in Walmart, and I got them just for the 500
spare bulbs it gave me ... Good luck with fixing your problem. Believe me, I
know how frustrating it can be, in my case, up a ladder, in the cold, with
it getting dark, and a pocket full of spare bulbs that keep slipping from my
frozen fingers !

Arfa