Those miserable cristmas lights


  #1  
Old 02-09-15, 03:49 AM
D
Member
Thread Starter
Join Date: Oct 2014
Location: usa
Posts: 8
Upvotes: 0
Received 0 Upvotes on 0 Posts
Those miserable cristmas lights

Hello all:
So a friend approaches me with a string of 50 christmas lights - those cheap little bulbs in the cheap green sockets with the fine wire on each side of the bulb base...And asks: "How can I use just 3 or 4 of these to illuminate some glass work I'm doing..."

Well, the first thing to do is plug in the string and see if they ALL lite, because if one doesn't work, none of them work. But have you ever looked at how these dudes are wired?

You start out with two wires from the plug, go to 3 wires at the first bulb and then a single wire from bulb to bulb until the last bulb - yep, three wires again. And of course there is a third wire in the bulb string wire bundle.

After much painstaking experiment using the first bulb (3 wire) the second bulb in the string and the last bulb (3 wire), you think a miracle has happened for the 3 bulbs lite but flash (BURN) out. No breaker trips because Murphy's Law kicks in which states in this case: "In any circuit with a fuse to protect it, the item protected by the fuse will blow first thus protecting the fuse..."

Well then you think and come to the conclusion these are being plugged into a 120v 20 amp protected wall outlet - not some 1.5 v battery, and yet no step down transformer anywhere in the string???? Can you imagine mainlining your cell phone to 120v direct without the protected charging cord?

So what's the mystery with these miserable things? Can it be done or is there a much better solution out there for my friend's needs - I'd love to tell him to use _________ and throw those #$%^&^# christmas lites away.

Thanks for your comments.
 
  #2  
Old 02-09-15, 04:51 AM
chandler's Avatar
Banned. Rule And/Or Policy Violation
Join Date: Dec 2005
Location: USA
Posts: 36,607
Upvotes: 0
Received 11 Upvotes on 10 Posts
Your string is a series/parallel block lighting. Several lights are tied together with single wiring. That entire block will go out if one bulb fails. The three wires carries a parallel circuit to the next block. It was a feeble attempt to do it right. I would opt for small LED lighting. They don't care about voltage too much, use little electricity, and can be wired in parallel from your plug. Of course you have to do some shopping, but Christmas lights would be at the bottom of my list for project lighting.
 
  #3  
Old 02-09-15, 04:56 AM
P
Temporarily Suspended
Join Date: Jul 2008
Location: NY
Posts: 10,265
Upvotes: 0
Received 0 Upvotes on 0 Posts
One year after Christmas, I neatly wrapped the lights, in a nice little package so that the following year, I wouldn't have to untangle the mess I had, in previous years. The following year I opened the box & they were a complete mess. No one touched them unless some gremlins found their way in & wrecked them. That was the end of Christmas lights until many years later, I was hired to hang some lights, on the front of a house. That job was a disaster.

What I didn't know was that newer sets have little fuses, in the wire ends. They just kept blowing, one after another. When I realized that there were fuses in the line, I asked the home owner & she had extras. I still think that gremlins exist & they despise Christmas.
 
  #4  
Old 02-09-15, 09:02 AM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Jersey
Posts: 66,020
Received 4,156 Upvotes on 3,732 Posts
A lot of technology goes into the making of Christmas light strings.

If you had a 100 light set, you would actually have two 50 lights sets wired in series/parallel as Chandler mentioned. A 150 light set would have three sets of 50 lights.

Once you know how many bulbs are in one string you divide the voltage by the bulb count to arrive at volt-per-bulb number. 12050=2.4volts

If you had a 35 lights set it would be 12035=3.5volts

That's why when you buy replacement bulbs they ask you how many lights are in the string as the bulb voltage is critical for long life.

So if you are connecting four bulbs in series from that 50 light set you'd have 2.4x4=9.6 volts. You'd need around a 9v supply to run 4 lights.
 
  #5  
Old 02-09-15, 12:55 PM
A
Member
Join Date: Mar 2010
Location: USA
Posts: 4,627
Upvotes: 0
Received 296 Upvotes on 271 Posts
The most common reason for failure of a string of Christmas lights is too many bulbs burning out. You can lose a few bulbs without any problem but the more that burn out without being replaced, the higher the voltage each of the remaining bulbs gets which shortens their life.

The second most common reason is a bulb becoming loose. In the old days (ca 1965) the mini-lights had screw in sockets and loose bulbs was the most common reason with too many burnouts being the second most common reason.

Other idiosyncrasies:

Another example of a 2 way set (2 series of 50 lights for a total of 100 lights). From the plug wire A goes to first socket. Coming out of socket are continuation of wire A going to light 3 and wire B (from other contact in socket)going to light 2.

At light 2 wire B enters the socket and continuing wire B comes out and goes to socket 3. Wire A skips past and goes to light 3.

At light 3 wire A goes into socket and continuing wire A comes out and goes to light 5. Wire B skips past and goes to socket 4.

And so on, one series subcircuit (A) is for the odd lights and the other series subcircuit (B) is for the even lights.

About the third wires, C, it goes from the plug skipping all the sockets until the very end, socket 100. Here it attaches to both wire A and wire B.

What if there is a (female) connector or receptacle at the far end to daisy chain another string of lights from?

Then (assuming the same 2 way set of perhaps 100 lights in two interwoven series strings) we have a fourth wire D.

From the first socket, the wire A from one (male) plug prong enters and out comes wire B going to socket 2 and wire D skipping all the sockets to the far end. Also the continuation of wire A comes out to go to socket 3.

At the far end, wire C is connected to wires A (from socket 99) and B (from socket 100) and also a continuation wire to the (female) receptacle. Wire D is only connected to the other terminal of the receptacle.
 
  #6  
Old 02-09-15, 01:11 PM
P
Temporarily Suspended
Join Date: Jul 2008
Location: NY
Posts: 10,265
Upvotes: 0
Received 0 Upvotes on 0 Posts
There is one good think about Christmas lights & that is I never have to touch them again. What's worse is Christmas music. It's impossible to avoid. Every store has it playing. Even the non commercial radio stations that I like sneak it in some way or another. Every day between Thanksgiving & New Years sucks. It is NOT the most wonderful time of the year. Summer is the most wonderful time of the year.
 
  #7  
Old 02-09-15, 03:45 PM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Jersey
Posts: 66,020
Received 4,156 Upvotes on 3,732 Posts
You're a mean one...... Mr Grinch
 
  #8  
Old 02-09-15, 03:57 PM
ray2047's Avatar
Member
Join Date: Mar 2006
Location: USA
Posts: 29,711
Upvotes: 0
Received 15 Upvotes on 13 Posts
Plenty of LEDs online that can be run from a wallwart.
 
  #9  
Old 02-09-15, 08:04 PM
P
Temporarily Suspended
Join Date: Jul 2008
Location: NY
Posts: 10,265
Upvotes: 0
Received 0 Upvotes on 0 Posts
LOL @@@@@@@@@@@@@@@@@@@ PJmax
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: