On 29 Nov 2006 05:51:21 -0800, "terry"
wrote:


ukwildcatfan wrote:
I have a quandry and would like some help on this matter. I need to
shorten christmas light strings to fit certain decorations but have no
idea how this is done. What I am using are the mini light sets with plugs
on both ends. Cutting the end off is not a problem. That is pretty
straight forward. I just need to shorten the length.

................................................. .................................................. ......................

Reading other posts;
.
We all seem to be assuming that the lights are those series strings.

But OP mentions "Plugs at both ends". In other words the input voltage
goes right to the far end so another set can be plugged in beyond it.

That suggests the light strings may 'not' be the type where all the
bulbs are in series and if one goes pop they all go out?


They are series. I included a wiring diagram of a typical string in
another post. There will be hot and neutral wires running straight
between the ends. The series of bulbs is connected to hot at one end
and neutral at the other. Fuses are in the male end.

But a word of warning some types have at least three wires and while
the bulbs are in series the input voltage is also carried to the far
end. Some of the 'hanging icicle type lights' seem to be of that type?

As well as most ordinary miniature light strings. Note that 2-series
are common. You will notice a point in the middle of the string where
only 2 wires are present. That's the point between the series. Icicle
lights often have 2 such points, since there are 3 series.

Tracing for dead bulbs in those, for my neighbour, last year, was a
nightmare!


It helps a LOT to use one of those $5 testers (that sense 120V across
a bulb, which happens only if it's bad).

Another common type of light strings uses bulbs (115 volt in North
America) that are each individually connected to 'both' wires. In that
case it wouldn't matter if you had one bulb or fifty on a string!


Have you actually seen any MINIATURE lights connected this way?

If they 'are' that type it may not be a big job to cut the strings into
shorter lengths of a few lamps each. .......... PROVIDED the cut end
which will have 115 to 120 volts AC across the cut off wire ends can be
properly insulated. Safety and insurance would be issues!

I would suggest that just using electrical tape on the end would not be
safe or acceptable.

Electrical tapes tends to come loose with age and exposure to weather.

Perhaps some kind of plastic liquid; the sort into
which you dip the handles of tools, several times, to give them a
coating would work and it must thoroughly adhere the cut end of the
wire?
--
26 days until the winter solstice celebration

Mark Lloyd
http://notstupid.laughingsquid.com

"Unlike biological evolution. 'intelligent design' is
not a genuine scientific theory and, therefore, has
no place in the curriculum of our nation's public
school classes." -- Ted Kennedy