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Hi, need help on my thought process here.

I got the Sub panel wiring figured out and ready to install. It's basically feeding off the main panel with a 50 amp breaker. #6 3 wire with ground (4 total) to the subpanel.

OPTION #1
On my sub panel I am planning on using 20 amp, double pole breakers. Basically (2) 20 amp breakers in one from what I am understanding.

Here is the biggest part of the question. From each 2x20 breaker, I will run 2 #12 wires to a single recepticle. The recepticles have a connector between the top and bottom that can be snipped off to create 2 circuits. I need to know if this is ok to do.

The top of the recepticle will go to the left side of each LOR and the bottom to the right side of each LOR.

To re-iterate... There will be 5 breakers total (each with 2x20 amps), going to each recepticle but split into two circuits. Each recepticle will have 2 extenstion cords leaving it and entering a single LOR.

OPTION#2
Just install 5 40 amp breakers, single #14 wire to each recepticle and run 2 extension cords to each LOR.

Are both of these even options and which setup is the better bet?

Thanks again.

Luke

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llbarnes wrote:


Here is the biggest part of the question. From each 2x20 breaker, I will run 2 #12 wires to a single recepticle. The recepticles have a connector between the top and bottom that can be snipped off to create 2 circuits. I need to know if this is ok to do.


It would really be three wires to each receptacle the 2 hots from the breaker plus a shared neutral. This is common is electric wiring. BUT,you should use GFIC receptacles. This will protect from getting shocked or shocking the neighbor's kids

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Luke, Having a 50 amp sub gives you 50 amps @ 240v and 100 amps @ 120v. You don't want to use double pole ganged breakers, which are for a 240v connection and connect them to single 120v outlets. Use a single breaker for each circuit. Fault tripping for a ganged breaker will cause you to lose 2 circuits if there is a trip.

Keep another thing in mind when you design your layout... you can easily wire 240v onto a single board if you isolate a 16 channel board into two 8 channel boards. It is best to use 2 breakers straight across(not next to each other as in a ganged) from each other on the same board.

For example, if you were to break the tabs on a double outlet and wire 1 circuit to the top outlet and a 2nd circuit to the bottom outlet... If the breakers are across from each other the outlets are at the same potential (120v) If the breakers are next to each other as in a ganged breaker, the differance between them is 240v.

As for the amperage, if you use a 20amp ganged breaker and wire that to a single board, you have potentially provided 40 amps @ 240v for a fault on that board. In terms of a dangerous shock hazard, this is way up there!

To be safe, my goal would be to have a set of single 15 or 20 amp breakers on the same 120v leg wired to a set of outlets. Have those outlets marked for 1 board, so as to keep it safe.

You really should consider GFCI outlets too. No matter how hard you try, you will be setting up a display that will have 240 volts between things in your yard. That's not a great recipe. Ground fault tripping really makes it safer.

Just my opinion.

jeff <---- Is a card carrying member of the IBEW for what it's worth...

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llbarnes wrote:

Hi, need help on my thought process here.

I got the Sub panel wiring figured out and ready to install. It's basically feeding off the main panel with a 50 amp breaker. #6 3 wire with ground (4 total) to the subpanel.

OPTION #1
On my sub panel I am planning on using 20 amp, double pole breakers. Basically (2) 20 amp breakers in one from what I am understanding.

Here is the biggest part of the question. From each 2x20 breaker, I will run 2 #12 wires to a single recepticle. The recepticles have a connector between the top and bottom that can be snipped off to create 2 circuits. I need to know if this is ok to do.

The top of the recepticle will go to the left side of each LOR and the bottom to the right side of each LOR.

To re-iterate... There will be 5 breakers total (each with 2x20 amps), going to each recepticle but split into two circuits. Each recepticle will have 2 extenstion cords leaving it and entering a single LOR.

OPTION#2
Just install 5 40 amp breakers, single #14 wire to each recepticle and run 2 extension cords to each LOR.

Are both of these even options and which setup is the better bet?

Thanks again.

Luke

As another poster has mentioned, for this scheme you would actually be running 4 wires to each receptacle, 2 hot wires, 1 neutral wire, and 1 ground wire. It will work by isolating the two halves of the outlet as you describe, but there are some disadvantages.

The biggest disadvantage is that there is no way to get GFI protection and this is really important for outside lighting. GFI receptacles can't be split to accomodate 2 circuits, although you could just install 2 separate GFI receptacles per circuit, instead of the single split receptacle, using the same wiring scheme.

The only thing you gain with this method is that you are running 4 conductors for 2 circuits instead of 6. The cost savings in the wire is probably negligible. I think you would be far happier in the long run if you install 10 separate single-pole 20A breakers, and run 12/2 w/ground from each one to 10 individual GFI receptacles.

Option #2 is definitely NOT a good idea! First, code-wise, standard duplex receptacles must be fed by a breaker rated at no more than 20 amps. Second, you would need larger wires (as in smaller gauge number), something like #8 for 40 amps. This would *really* be unsafe, so please don't even consider that approach.



-jim-

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jeffmill wrote:

Luke, Having a 50 amp sub gives you 50 amps @ 240v and 100 amps @ 120v. You don't want to use double pole ganged breakers, which are for a 240v connection and connect them to single 120v outlets. Use a single breaker for each circuit. Fault tripping for a ganged breaker will cause you to lose 2 circuits if there is a trip.

Keep another thing in mind when you design your layout... you can easily wire 240v onto a single board if you isolate a 16 channel board into two 8 channel boards. It is best to use 2 breakers straight across(not next to each other as in a ganged) from each other on the same board.

For example, if you were to break the tabs on a double outlet and wire 1 circuit to the top outlet and a 2nd circuit to the bottom outlet... If the breakers are across from each other the outlets are at the same potential (120v) If the breakers are next to each other as in a ganged breaker, the differance between them is 240v.

jeff <---- Is a card carrying member of the IBEW for what it's worth...


Jeff I have to disagree with you here. I am pretty sure that the NEC requires that when 2 separate circuits are run to the same receptacle that they be on a mechanically ganged dual breaker. Also, I am assuming that he is only planning on running a single neutral conductor, and wiring the receptacle as you describe would put the sum of both receptacle's current draw (up to 40A) on the neutral, whereas if using a 2-pole breaker the neutral conductor sees only the difference current.

I see few advantages and many disadvantages to the use of 2 circuits per receptacle for this type of application.

-jim-

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One thing that should be considered when wiring high current feeds is the outlet type. Since there is only one plug typically used to feed one side of the controller, there is only one path for current to flow. Most outlets sold in the electrical section of your favorite home supply store is typically rated at 15 amps. You really want the 20 amp versions. They are made with heavy duty contacts tested to carry 20 amps. Yes, they are much more expensive (especially the GFCI ones). They also look different - the neutral slot (longer one) has a horizontal extension to the outside of the outlet. Also 20 amp circuits should be wired with 12 gage as stated earlier. 14 is for 15 amp circuits.

Don't make your show a "Fire-O-Rama" one!

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jstjohnz wrote:

Jeff I have to disagree with you here.
-jim-

There is nothing in the National Electric Code that approves using a 240V ganged breaker for 120V use. That is clearly his intent here. I don't care to get in a war of wits. The ganged breaker you speak is not available for residential use. Using a ganged 240V breaker is not in any way a good idea. Don't miss the point. Placing 240V between the hots on a controller board is dangerous! That is what the end result will be. I explained in PM why I don't think he should wire his outlets with these ganged breakers.

Over and above all else stated here is the fact that it is safest to wire an individual breaker to a GFCI, and plug your board into the GFCI. 1 Breaker, 1 circuit, and in most cases 2 outlets. I don't in any way condone violating code, but my suggestion of placing 2 circuits on one set of outlets by using 2 breakers directly across from each other is much safer than using a ganged 240v breaker.

I hate to ruffle feathers here and don't want to upset anyone, but arguing these points creates an environment that could lead someone to believe that using a ganged 240v breaker for this application is what is required by code and that is the farthest thing from the truth. It is also very dangerous.

Sorry if I offend anyone with this post, but I'd much rather have you be angry with me for something I've said and still be alive. Or even worse, find out you had a youngster get between 2 sets of minis on your front lawn that had 240v between them and the breaker didn't trip because it was ganged and the little guy was only drawing 30 of the 40 amps required to get it to trip! Harsh? Worst case scenario? I'll tell you a little story about Mr. Murphy the optomist. It has to do with kids....

It was a beautiful 4th of July afternoon. There were 2 adults and 3 teenagers assigned to watch the children in the pool all day. After many hours we figured they were worn out and began to pack them away a few at a time. I went around front to see some of our guests off. Wasn't away for more than a minute and heard someone screaming bloody murder! By the time I got back to the pool, my sister-in-law had him out of the water and was whacking him on the back. He was about 3 years old, and as I got to him he coughed and started breathing again. He was blue, and according to his savior he was posturing at the bottom of the pool when she saw him.

I'm a firm believer of the worst case scenario. I will make sure my lights are safe. You will be able to run through them wet and naked, and they'll just turn off so we don't have to see that.

PS As soon as all the guests were gone, I took a chainsaw to the pool. I really wish I has set up a video camera for that.

jeff

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Ok, here is a picture of my new subpanel. It's a 100w with only 6 spaces. That is why I was thinking that the 5 dual 20 amp breakers would have been perfect. Yes, the sub is going to be fed by a 50 amp feeder, but the sub panel will never be used for more than 50 amps.

So, knowing what my sub panel looks like now, how would you do this. Can I use the new 1/2 size 20 amp breakers to get a total of 10 circuits going to 10 gfci's?

I'd much rather spend the extra money on 10 gcfi's than the 2x20 amp breakers.

Thanks again for everyone's help.

Luke


Attached files 54277=3181-DSC01569smaller.jpg

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jeffmill wrote:

jstjohnz wrote:
Jeff I have to disagree with you here.
-jim-

There is nothing in the National Electric Code that approves using a 240V ganged breaker for 120V use. That is clearly his intent here. I don't care to get in a war of wits. The ganged breaker you speak is not available for residential use. Using a ganged 240V breaker is not in any way a good idea. Don't miss the point. Placing 240V between the hots on a controller board is dangerous! That is what the end result will be. I explained in PM why I don't think he should wire his outlets with these ganged breakers.


Disclaimer: I (and some others), I think have been discussing a special type of circuit where two separate breakers, or a 2-pole breaker feed the two halves of a split duplex receptacle using a common neutral wire. I thought that was the intent of the originator of the thread, now I don't feel that is the case. In any case, this post is a continuation of that discussion since it is a commonly used technique...

Jeff,

Perhaps we have some confusion here regarding terminology. I am talking about a 2-pole breaker that occupies two adjacent panel spaces and is typically used to power 240V loads such as ranges, dryers, etc. I'm not sure if this is what you are referring to as a '240V ganged breaker' or not, but if it is, they are surely available for residential use and it would be rare to see a panel that doesn't contain at least one.

The type of circuit we are referring to here, a split duplex receptacle fed by 2 hot wires, is referred to in the NEC as a multiwire circuit. Not only is a 2-pole breaker approved, it is required. The newest print copy I have is 1996, and it is covered in section 210-4. "(multiwire circuits)...shall be provided with a means to disconnect simultaneously all ungrounded connectors at the panelboard". Later NEC versions have this under 210.7. Prior to 2005, 2 separate but mechanically ganged breakers were acceptable, but I believe now that a single 2-pole breaker is required.


jeffmill wrote:"Placing 240V between the hots on a controller board is dangerous!"

No, it is not. In fact the LOR controllers can be run with 240V hot to neutral, as used in many other countries.

Think about this: For a typical large LOR installation, powered from several different circuits, there is a high probability that any given LOR controller will be powered from 2 circuits that happen to be on different legs of the AC supply.

For the type of circuit being described here, ie a split receptacle, the two hots MUST be on 2 different legs. If they are not then the neutral current could be a maximum of 40 amps, and the neutral terminals on a 120V duplex receptacle are not rated for 40 amps. This is one of the reasons for requiring a 2-pole common trip breaker: If two separate breakers were used, it's possible that at some future time an electrician working on the panel might unknowingly relocate one of those breakers in such a way that they were no longer on separate legs, thus leading to current on the neutral conductor in excess of what the conductor was rated for.

jeffmill wrote:
Sorry if I offend anyone with this post, but I'd much rather have you be angry with me for something I've said and still be alive. Or even worse, find out you had a youngster get between 2 sets of minis on your front lawn that had 240v between them and the breaker didn't trip because it was ganged and the little guy was only drawing 30 of the 40 amps required to get it to trip!

We are in complete agreement re the need for GFI protection.
Your above scenario though isn't really valid. The trip current for a hot-to-hot overload across 2 20A circuits on opposite legs is still 20A, not 40A. Moot point though, since currents of well under an amp can cause electrocution. Overcurrent protection devices don't really provide any protection against electrical shock. I have received several electrical shocks in my lifetime and never once did a breaker trip as a result.

-jim-

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llbarnes wrote:

Ok, here is a picture of my new subpanel. It's a 100w with only 6 spaces. That is why I was thinking that the 5 dual 20 amp breakers would have been perfect. Yes, the sub is going to be fed by a 50 amp feeder, but the sub panel will never be used for more than 50 amps.

So, knowing what my sub panel looks like now, how would you do this. Can I use the new 1/2 size 20 amp breakers to get a total of 10 circuits going to 10 gfci's?

I'd much rather spend the extra money on 10 gcfi's than the 2x20 amp breakers.

Thanks again for everyone's help.

Luke


The breakers you are describing are tandem breakers, two single-pole breakers that mount in a single panel space. Some panels accept these, some don't, some accept them only in certain slots.

To get 10 circuits you would need to be able to use tandem breakers in at least 4 slots.

You would need to wire these as 10 separate circuits, each with a 3-conductor cable, hot, neutral, and ground. To add just a bit more complication, you will need a separate ground buss for this panel. Ready to call the electrician yet???

-jim-

I'm still not sure what you mean about spending money on 10 gfcis rather than 2x20 breakers. Are you talking about double-pole GFI breakers?

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Luke,
It seems that you are working on a learning curve here and I applaud that. We've also got some very knowlegeable people here to help, so you're in the right place. From what I'm reading, you may be using terms incorrectly (now watch me get chewed out for the same thing).

First, let's look at your box that you provided a picture for. In the lower right you will see a connection block that is connected to a power bus bar that is plainly in view. In the upper left corner of the junction block, you will see a connection terminal that is attached to a second buss bar that is pretty hidden in the picture. Across the top, you see the numerous neutral attachment points (exposed bar with lots of screws). The two bus bar connections are for the two hot wires (black & red I believe is standard) and the neutral bar is for both the white & bare ground wire.

Now for how this box transmits power to the output of the breakers. The bottom bus is connected to a metal contact point in slots 1, 3, & 5. The top bus is connected to slots 2, 4,& 6. Notice that the metal contact points are in slots that are about 1/2" wide. That is the width of a normal 110V breaker. A double ganged breaker takes two of those slots up. Each bus provides 110V relative to the neutral. But since the two buses are out of phase with each other (one provides 110V positive while at the same moment in time, the other provides 110V negative), you get 220V when you use a double ganged breaker.

Bottom line is that if your breakers are only using one slot, they are 110V breakers. Two slots=220V. Using the 1/2 size breakers provide 110V since they only make contact with one bus bar.

My final comment - Since I seriously doubt that you have 220V lights that you want to control with a LOR, everything you will be working with will be 110V and thus you should have no breakers that consume two slots.

Hope this helps you understand that most of the discussion about 220V really does not apply to your situation.

Ken Mays

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I thought he was talking about using the ganged 2 pole breaker so he could double his current capacity using both sides of the transformer (hi and low bus) In that case, wouldn't he want to use the ganged breaker?



mysticturner wrote:

Luke,
It seems that you are working on a learning curve here and I applaud that. We've also got some very knowlegeable people here to help, so you're in the right place. From what I'm reading, you may be using terms incorrectly (now watch me get chewed out for the same thing).

First, let's look at your box that you provided a picture for. In the lower right you will see a connection block that is connected to a power bus bar that is plainly in view. In the upper left corner of the junction block, you will see a connection terminal that is attached to a second buss bar that is pretty hidden in the picture. Across the top, you see the numerous neutral attachment points (exposed bar with lots of screws). The two bus bar connections are for the two hot wires (black & red I believe is standard) and the neutral bar is for both the white & bare ground wire.

Now for how this box transmits power to the output of the breakers. The bottom bus is connected to a metal contact point in slots 1, 3, & 5. The top bus is connected to slots 2, 4,& 6. Notice that the metal contact points are in slots that are about 1/2" wide. That is the width of a normal 110V breaker. A double ganged breaker takes two of those slots up. Each bus provides 110V relative to the neutral. But since the two buses are out of phase with each other (one provides 110V positive while at the same moment in time, the other provides 110V negative), you get 220V when you use a double ganged breaker.

Bottom line is that if your breakers are only using one slot, they are 110V breakers. Two slots=220V. Using the 1/2 size breakers provide 110V since they only make contact with one bus bar.

My final comment - Since I seriously doubt that you have 220V lights that you want to control with a LOR, everything you will be working with will be 110V and thus you should have no breakers that consume two slots.

Hope this helps you understand that most of the discussion about 220V really does not apply to your situation.

Ken Mays

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Using a 220V does not double your current capacity. Your power doubles. Power = Volts * Amps. By using 220 you get twice the power for the same amperage. In a 110V box with multiple breakers, you are using both sides of the transformer. As you walk down the breaker box, the 110 breakers are switching sides of the transformer.

While you can use a 220V line to run 110V stuff by splitting off each hot, you create the opportunity for FIRE :shock:. The reason why is that in a cable all 4 wires are the same guage.

Here's what happens in a 'true' 220V environment (like an electric stove). The current flows out one hot and returns on the other hot. The neutral carries no current. Note I said 'true' 220V environment. If you look at an electric dryer, there probably is current on the neutral. Internal to the dryer, they use one side to run the motor, the other to run the heat coils. Result is that the neutral carries the difference in the two, an amount that is less than either hot leg.

Now for the Fire situation. If you split a 220V line into two 110V lines, then the neutral carries the current of both 110 circuits. On a 220V line, if the wire you are using is rated for 20 amps at 220V using 4 wires (2 hot, 1 neutral, 1 ground) and you have a 20A double breaker, you are OK. Split the circuit into two 110V lines (without a subpanel) and you can now pull 20A down each hot, push the total down the neutral (which does not have a breaker on it). Result is that that 20A rated neutral wire is now carrying 40A and it is very hot and catches on fire.

That's why it's critical to install a subpanel and size both the supply breaker and the subpanel breakers correctly.

Ken Mays

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Except that the current from the top of the transformer is negative the current from the bottom of the transformer so the curret cancels in the neutral it doesn't double. So, with two 110V sides fully loaded to 20 amps the neutral carries a net load of zero. That is why the neutral is allowed to be sized smaller than the mains. It doubles your current capacity since you are only allowed to pull 20 amps from each side. If you use both sides of the transformer you get 40amps total (equals the same power as 20amps times 220V = 20 amps * 2 * 110V







mysticturner wrote:

Using a 220V does not double your current capacity. Your power doubles. Power = Volts * Amps. By using 220 you get twice the power for the same amperage. In a 110V box with multiple breakers, you are using both sides of the transformer. As you walk down the breaker box, the 110 breakers are switching sides of the transformer.

While you can use a 220V line to run 110V stuff by splitting off each hot, you create the opportunity for FIRE :shock:. The reason why is that in a cable all 4 wires are the same guage.

Here's what happens in a 'true' 220V environment (like an electric stove). The current flows out one hot and returns on the other hot. The neutral carries no current. Note I said 'true' 220V environment. If you look at an electric dryer, there probably is current on the neutral. Internal to the dryer, they use one side to run the motor, the other to run the heat coils. Result is that the neutral carries the difference in the two, an amount that is less than either hot leg.

Now for the Fire situation. If you split a 220V line into two 110V lines, then the neutral carries the current of both 110 circuits. If the wire you are using is rated for 20 amps at 220V using 4 wires and you have a 20A double breaker, you are OK. Split the circuit into two 110V lines (without a subpanel) and you can now pull 20A down each hot, push the total down the neutral (which does not have a breaker on it). Result is that that 20A rated neutral wire is now carrying 40A and it is very hot and catches on fire.

That's why it's critical to install a subpanel and size both the supply breaker and the subpanel breakers correctly.

Ken Mays

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Jim,

It's listed in NEC 2002 & NEC 2005 under 210.4 (;):

(:D Dwelling Units. In dwelling units, a multiwire branch circuit supplying more than one device or equipment on the same yoke shall be provided with a means to disconnect simultaneously all ungrounded conductors at the panelboard where the branch circuit originated.

NEC 2002 under 210.7 (B) says:
(B) Multiple Branch Circuits. Where two or more branch circuits supply devices or equipment on the same yoke, a means to simultaneously disconnect the ungrounded conductors supplying those devices shall be provided at the point at which the branch circuits originate.

and NEC 2005 under 210.7 © says:
© Multiple Branch Circuits. Where more than one branch circuit supplies more than one receptacle on the same yoke, a means to simultaneously disconnect the ungrounded conductors supplying those receptacles shall be provided at the panelboard where the branch circuits originated.

Hope this info is helpful.

Tom

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tsmith35 wrote:

Jim,

It's listed in NEC 2002 & NEC 2005 under 210.4 (;):
(:D Dwelling Units. In dwelling units, a multiwire branch circuit supplying more than one device or equipment on the same yoke shall be provided with a means to disconnect simultaneously all ungrounded conductors at the panelboard where the branch circuit originated.

NEC 2002 under 210.7 (B) says:
(B) Multiple Branch Circuits. Where two or more branch circuits supply devices or equipment on the same yoke, a means to simultaneously disconnect the ungrounded conductors supplying those devices shall be provided at the point at which the branch circuits originate.

and NEC 2005 under 210.7 © says:
© Multiple Branch Circuits. Where more than one branch circuit supplies more than one receptacle on the same yoke, a means to simultaneously disconnect the ungrounded conductors supplying those receptacles shall be provided at the panelboard where the branch circuits originated.

Hope this info is helpful.

Tom




Yeah, but what exactly is the definition of a yoke?

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Just some added Information on sub panels:

This would be a good time to talk about the neutral bonding jumper.

In most panels you will find that the neutral buss bar (the common bar that is mostly isolated from the panel case), has either a long brass machine screw, or a metal strap of some kind that connects the neutral bar to the panel case, or ground.

In a subpanel, the neutral must be totally isolated from ground, so you must remove this screw or strap. The neutral and the ground can only be bonded in one location in a residential service, and that is in the main panel.

and for more information on this go to > Installing a subpanel

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Ok, I think I have this down pat now. Will get the additional bar for the grounding. Will undo the neutral strapping to the case. Won't jump across more than one slot and will stick to using the (5) 2x20 amp breakers to get my 10 circuits.

Thanks again for all of your help. I will put up some pictures when I am done.

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Mercy. All this just to add an extra string of Christmas lights :?

Special note to newbies. Electricity is dangerous stuff. It's worth the time and money to hire a licensed electrician to provide any extra capacity you might need for a growing Christmas light display.

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