Can a string of Christmas lights be cut down? These are the mini
lights that come in a string of 100.
It looks like they are wired in series which leads me to believe that
each bulb is a little over 1 volt (about 1/100 of 110). That would
mean that cutting the string in half would double the voltage and burn
out the bulbs.
My problem is that we have this "hierloom" star for the top of the
tree. It is made of crystal and tinsel. There is a mini-string of
about 15 tiny white bulbs woven in and around the arms of the star. I
have repaired the string as many times as I can. I would like to
replace it, but I only need a string on about 15 bulbs.
I thought of using the extra lights on the tree, but the wife wants
colored lights on the tree and white in the star.
Replace just some of the colored bulbs with clear for the star on one of
your strings for the tree.
You are correct that they are in series so can't be cut down without
replacing the bulbs to match the new voltage.
These mini bulbs come in several different voltages to match the number in a
single series string. Some sets come with more than one series string wired
in parallel with each other so you can't always just count the total number
of bulbs to determine their voltage.
You can buy sets of different number of bulbs so may be able to find a short
string of 15 or 20 with the higher voltage bulbs needed.
At 15 bulbs, that's about 8 volts. Cut a string down to 15 sockets, then get
a couple of packages of "6-8 volts" replacement bulbs to use. There will
probably be a third wire in the string which is now useless. Remove it.
You just need to use 12 volt bulbs used in 10 to 15 light strings.
Since this is an "heirloom" and is worth restoring you could buy a cheap 10
to 15 light star and remove the string of lights to use in your star. It
would be probably easier and cheaper than cutting down an existing string
and replacing all the bulbs.
Tree toppers use 10 to 12 volt bulbs. You can buy them in packs of 4
or 5 at most stores (this time of year). Why not just buy all news
bulbs and replace all of them. Of course if the wiring or sockets are
bad, you can use those from an old string as long as the bulbs fit,
and you dont mind the time needed to do it. You;ll end up splicing
the return wire to the plus somewhere. I'd solder the connection and
tape well, or use shrink tubing.
Yes, you CAN NOT use the original bulbs, and they are probably 1.5
volters on a 100 string.
By the way, I think they sell the bulbs in four types
3 - 4 volt
6 - 8 volt
10 - 12 volt.
And if you are real creative, you could use super bright LEDs
The strings of 100 I have come in three varieties.
Some are just 100 bulbs in series, using 1.5 volt
bulbs. Some use 3 v. bulbs and are actually two
strings of 50 end to end. Others are 5 strings of
20 6 v. bulbs. Take out one bulb and see how many
go out. I have several times cut up strings of 100
6 v. bulbs when I needed a smaller multiple of 20
lights for a special project.
You have several choices:
Replace the string with the correct number of
sockets from a larger string but use the bulbs
from the original old string, or with other bulbs
rated at 7 to 9 volts.
Find a short string to use. My local dollar
store has strings of 20 bulbs.
If you find a string of 100 that is made of 5
strings of 20 6 v. bulbs, use one 20 bulb string
from it to do your rebuild.
There is a very slim chance that the old set is
made with 120 v. bulbs in parallel. If so you don't
want to swap bulbs between it and any of the now
common series lights.
Also be aware that most of the current lights
are supposed to keep on if a bulb burns out. It
is better in theory than in practice. They do
this by shorting out when the filament breaks.
It is usually ok to shorten a string by a couple
lights but not by much. If it is shortened at all
it is even more important to replace burned out
bulbs soon after they die. If too many burn out,
the voltage to the others goes up enough that they
will go fast, then the fuse.
If you do any string rebuilding, make sure you
use a plug with a fuse. I think all new strings
now have fuses in the plug.
Bob <valen (at) trust-me (dot) com>
On Fri, 19 Dec 2003 01:33:40 GMT, email@example.com (Bob Joesting)
I would not use burnt out bulbs if there are too many. Just paint
them black or better yet, hang them below the tree topper in the tree.
So that's how the bulbs work when they burn out.....
I always wondered that.
I know only enough to be dangerous, but, since he plans to keep this
heirloom for a while, is there a way he could fashion a string of white
LED's in series with an appropriate sized resistor? Would he have to use a
plug-in transformer to drop the voltage?
I know this would be pricey, and tedious, but is it doable? This one time
cost and trouble might be worth it if he never had to fool with making the
thing work in future years. The "bulbs" would outlast he and his wife both?
Just a thought, maybe it is ridiculous, but I've always wondered....
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