AC Power cord - splicing

[Mike]

Hi All,

I have a couple strings of new Halloween lights, which are essentially like
the small incandescent bulb Christmas lights (not LED) that plug directly
into AC mains (120V). I would like to splice several of these lines
together to make one long string of Pumpkin lights. Each run of lights (10
lights/run) is terminated with a polarized 2-prong plug. The way they are
constructed, you basically have to connect each line to an AC power src.
The plugs are cascadeable but this enforces a star like configuration which
is less desirable.

Now, the real question, I would like to splice 4 runs in total, together,
hence 40 bulbs total and the safety warning label says not to exceed 210
lights so I am well under the max load rating. The wiring is insulated 20
AWG stranded copper. What is the best way to insulate each joint? My
approach is to use a "Western Union Splice", solder, and wrap 1-2
revolutions of 600V electrical tape around each joint and slide over some
standard heat shrink tubing to seal the deal. My question for the group is
whether this combined electrical tape and heat shrink is adequate enough to
_safely_ insulate these joints from electrical shock?.

How does one properly interpret the 600V rating on black electrical tape? I
would _assume_ that applies to a single layer of the tape. Theoretically
speaking, would the tape alone be enough to insulate the joint to prevent
electrical shock? What about the standard electronics hobbyist grade heat
shrink? What is its insulating properties? Is it similar to electrical
tape in terms of insulating properties?

Thanks in advance,

Mike

 

[[email protected]]

Mike wrote:
.. . .

How does one properly interpret the 600V rating on black electrical tape? I
would _assume_ that applies to a single layer of the tape. >
Thanks in advance,

.. . .

I believe it means that you could put a 600V potential (wire) on one
side of the tape and a ground or return wire on the other side and
there would be no arc or no electrical current that would flow through
the tape into the two wires. My assumption would be that it applies to
a single layer also.

 

[Homer J Simpson]

The way they are constructed, you basically have to connect each line to
an AC power src. The plugs are cascadeable but this enforces a star like
configuration which is less desirable.

If these are series strings this won't work.

 

[Rheilly Phoull]

Hi All,

I have a couple strings of new Halloween lights, which are
essentially like the small incandescent bulb Christmas lights (not
LED) that plug directly into AC mains (120V). I would like to splice
several of these lines together to make one long string of Pumpkin
lights. Each run of lights (10 lights/run) is terminated with a
polarized 2-prong plug. The way they are constructed, you basically
have to connect each line to an AC power src. The plugs are
cascadeable but this enforces a star like configuration which is less
desirable.
Now, the real question, I would like to splice 4 runs in total,
together, hence 40 bulbs total and the safety warning label says not
to exceed 210 lights so I am well under the max load rating. The
wiring is insulated 20 AWG stranded copper. What is the best way to
insulate each joint? My approach is to use a "Western Union Splice",
solder, and wrap 1-2 revolutions of 600V electrical tape around each
joint and slide over some standard heat shrink tubing to seal the
deal. My question for the group is whether this combined electrical
tape and heat shrink is adequate enough to _safely_ insulate these
joints from electrical shock?.
How does one properly interpret the 600V rating on black electrical
tape? I would _assume_ that applies to a single layer of the tape.
Theoretically speaking, would the tape alone be enough to insulate
the joint to prevent electrical shock? What about the standard
electronics hobbyist grade heat shrink? What is its insulating
properties? Is it similar to electrical tape in terms of insulating
properties?
Thanks in advance,

Mike

Do your local regs allow soldering of flexible leads ??

 

[Mike]

Each bulb is wired in parallel so a single burnt bulb won't compromise the
rest of the working lights.

 

[Mike]

Good question. I didn't realize there might even be regulations pertaining
to this type of soldering. Can you help me understand what the technical
implications of soldering flexible leads are?

To be safe, should I just stick with the Western Union joint and heat shrink
it? That joint should be physically durable enough I believe and by the
sounds of it, 600V electrical tape should eliminate the shock hazard.

I am also still curious though, what the electrical insulating properties of
standard hobbyist heat shrink in terms of eliminating the shock hazard?

 

[Martin]

Each bulb is wired in parallel so a single burnt bulb won't compromise the
rest of the working lights.

If they are like the christmas lights mentioned earlier they are not.

Those are in series, with an element in the base that forms a short if
the bulb burns out.
The short then lets the rest of the string keep burning.

Martin

 

[Homer J Simpson]

Each bulb is wired in parallel so a single burnt bulb won't compromise the
rest of the working lights.

OK. So each lamp is rated 120 volt?

Don't even think about 'splicing'. It violates code and is very dangerous.
If you have a fire and they find this they can cancel your insurance.

Go to a dollar store and buy extension leads. Run them parallel to the
strings to carry the current to each string. They are rated for this. At a
stretch you could attach a socket to the end of each lead, but the fact that
they are not designed to do this concerns me and I wonder about the current
rating of the flex cord used.

 

[Martin]

If they are like the christmas lights mentioned earlier they are not.

Those are in series, with an element in the base that forms a short if
the bulb burns out.
The short then lets the rest of the string keep burning.

Martin

Doh ... I reread the original post and saw that there are only 10
bulbs/string,
which would probably be the bigger lights, which are in parallel.

However, you still shouldn't attempt to splice them. You said the
wiring was 20 awg,
This is very thin, and has a low current rating (2 amps according to
one online source)
If the manufacturer followed standard practice, I'd bet thats the
thinnest (i.e. cheapest) wire that will support all the bulbs on the
string.

Add 30 more bulbs in parallel and you quadruple the current at the base
of the strand.
The 210 bulb max that you quoted is if they are connected the way they
are intended, and has no relevance to what you intend to do.

When it catches fire, you're homeowners will not pay if they find out
you modified it.

Martin

 

[James Thompson]

Good question. I didn't realize there might even be regulations
pertaining to this type of soldering. Can you help me understand what the
technical implications of soldering flexible leads are?

To be safe, should I just stick with the Western Union joint and heat
shrink it? That joint should be physically durable enough I believe and
by the sounds of it, 600V electrical tape should eliminate the shock
hazard.

I am also still curious though, what the electrical insulating properties
of standard hobbyist heat shrink in terms of eliminating the shock hazard?

Do your local regs allow soldering of flexible leads ??

AS others have said, It wont work like that. Strings meant to be connected
in series have at least 3 wires. One way to tell is remove 1 bulb from the
string and see if it lights the rest. BTW, soldering flexible wire makes a
rigid point where the wire will break easily.

 

[[email protected]]

Hi All,

I have a couple strings of new Halloween lights, which are essentially like
the small incandescent bulb Christmas lights (not LED) that plug directly
into AC mains (120V). I would like to splice several of these lines
together to make one long string of Pumpkin lights. . .

Your post brings to mind an incident that occured in Utah 13 years ago.
Here's an excerpt from a website:

"On December 15, 1993, fire swept through the stately Utah Governor's
Mansion. The cause: faulty wiring on the Christmas tree in the Grand
Hall.

Smoke traveled quickly from the hall to the nearby stairwell, which
channeled heat and smoke up through the house and out the roof nearly
destroying the dome over the staircase.

Fortunately, the governor's family (Governor Leavitt was not in the
mansion at the time of the fire) and staff were able to alert the fire
department and escape without injury. . ."