Install Christmas Lights Like a Pro with Bulk, Empty Socket Light Line

Empty Socket Bulk Light Line

We’ve all see the businesses and homes that are outlined with absolutely perfect perimeter lighting. Every bulb is exactly in line with the next bulb and every dormer, ridge row and architectural structure is cleanly outlined with no extra cord or bulbs hanging off the end. When done correctly, perimeter lighting can take an ordinary lighting project and turn it into a work of art. It’s obvious, looking at projects such as the one pictured above, that this type of high end lighting can only be achieved by professionally trained installers, right? Actually, no, anyone can achieve this same high end look with just a little bit of planning and using the right materials. If you’ve ever stood on a ladder to paint, then you already have all the skills you need to install perimeter lighting like a professional.

Choosing the Correct Empty Socket Light Line

Empty Socket Bulk Light Line Image

When it comes to installing perimeter lighting like a pro, the #1 rule is to buy the correct type of cord. This is where most people go wrong. They go to their local hardware or big box retail store, buy several boxes of pre-made C7 or C9 stringer sets and then attempt to install this around the perimeter of their home. The problem with this type of cord is that it generally comes in 25 or 50 foot sections with the plugs molded onto the cord and the bulbs already inserted into the sockets. With this pre-molded cord, when you get to the end of a run, you are stuck with trying to figure out what to do with the left over cord. This is why professional installers never use stringer sets for perimeter lighting. Instead they use either C7 or C9 bulk light line.

Bulk light line, also called empty socket light line can be purchased by the foot or in 500′ or 1,000′ spools. When using this type of cord, you simply measure out how much you need, cut the cord, screw in the bulbs and then add a slide on male and female plug. There’s no electrical experience needed and the plugs simply slide onto the cord.

Since you are able to cut the cord, you can now customize the cord length to the area you are working. This prevents that age old problem of having extra sockets and bulbs left over. We’ve all seen the houses with perimeter lighting where the homeowner took the left over cord and bulbs and strung them from the edge of the house, down to some bushes and tried to hide them in the foliage. With bulk light line, this is no longer a problem. Simply cut the cord and add your male to one end and your female to another. 

When it comes to choosing your light line, you have a variety of options available. These include the socket base size (C7 or C9), gauge of the cord, the color of the cord and the spacing between sockets. Let’s take a quick look at each of these.

Cord Socket Size – When it comes to the socket base size, you can choose between C7 or C9. For most structural perimeter lighting, C9s are the most commonly used. If lighting displays or small structures, then C7s work well.

SPT-1 or SPT-2 – SPT-1 or 2 refers to the thickness of the insulation on the cord. SPT-2 has thicker insulation than SPT-1. If you are installing the light line only for the holiday season, we recommend SPT-1. If you are looking to leave your cord up for more than 3 months at a time, then the extra thickness of the insulation on SPT-2 might be a good choice, however, if you plan on keeping the light line up on a year round basis, then it’s recommended that you invest in a heavier weight cord with nylon sockets. This type of cord is designed to hold up better  for longer term use.

Color of the Cord – The most popular cord color is white or green. At times you may come across brown or black, but these colors are hard to find and tend to be more expensive due to the limited production runs at the factories. Typically, green accounts for about 70% of our cord sales and white the remaining 30%.

Socket Spacing – Spacing between sockets can range from 4″ all the way up to 36″. The most common spacing is 12″ with 9″ or 6″ frequently being used on small structures with more details that need to be outlined.

Choosing the Correct Bulbs

Once you’ve decided on the type of cord, it’s time to select the bulbs. The first question you’ll need to answer is whether to go with incandescent bulbs or LEDs. LEDs have definitely gone mainstream and we sell significantly more LEDs these days than incandescent. Despite the fact that they cost 5 or 6 times more, most Christmas enthusiast and virtually all commercial customers we work with exclusively use LED retrofit bulbs. Between the power savings, the long bulb life and the illumination intensity, LEDs are unbeatable.

While we are big fans of LED retrofit bulbs, we have heard numerous horror stories where people have spent hundreds or even thousands of dollars on LED bulbs, only to get burned due to high failure rates and poor illumination intensity. We recommend sticking to either Minleon USA LED retrofit bulbs or Christmas USA LED retrofit bulbs. These are the only two manufacturers we use for our own installation jobs and haven’t found any other bulbs on the market that hold up as well as bulbs from these two high quality manufacturers.

Despite the advantages of LED retrofit bulbs, you may have to settle for incandescent bulbs due to budget constraints. There’s a big price difference between LED and incandescent bulbs and sometimes there’s just not enough money to make the investment into LEDs. The good news with incandescent bulbs is that because they do not contain any of the complex electronics that LEDs do, there’s not much of a difference in the bulbs from one manufacturer to another. So for incandescent bulbs, it’s not necessary to pay more in order to get a decent quality bulb.

Choosing the Correct ClipsAll In One Light Hanging Clip

When it comes to perimeter light line, the completed project is only as good as the clips you use. Picking the wrong clips, or going with a low cost retail grade clip can quickly ruin all your hard work. Nothing looks better than clean, straight perimeter light lines.

In order to achieve a professional look using light line, there are a few things to keep in mind:

  • Only use commercial grade clips.
  • One clip per socket, regardless how close the spacing between sockets.
  • Use the correct clip for the type of structure you are attaching the empty socket light line to.

Not sure which clip to use? Take a look at our Guide to Light Hanging Clips – Attachment Clips and Hardware.


When it comes to using bulk, empty socket light line, the electrical is very straight forward. All you need is a male slide on plug on one end of your run and a female on the other end. Once your male and female are on the cord, you simply plug it in to a regular extension cord and you’re good to go. When it comes to choosing the proper males and females, you’ll want to make sure they match the specs on the light line. For example if you are using SPT-1 cord, which is the most commonly used, you’ll want to use SPT-1 males and females. For SPT-2 cord, be sure the plugs are SPT-2. The great thing about slide on plugs is they are very easy and require no electrical experience. For a brief step by step guide to installing these plugs, see our blog listing for Installing a Slide On Plug.

When it comes to how many bulbs you can run on a single line, we recommend no more than 300 bulbs. For most applications, you’ll be well under this number, but if you are doing long runs, then be sure that you do not put more than 300 bulbs on a single cord.

Putting it All Together

Once you’ve got the cord, bulbs, clips and plugs, you’re ready to go. Most people that decide to use professional grade C7 or C9 light line are amazed at how easy it actually is and how much better it looks than the traditional C9 stringer sets. The first year’s installation will take a little longer, but once you’ve got all the cord cut, bulbs inserted and plugs installed, the year after year installations are a breeze. You’ll no doubt be the envy of your neighborhood.



  1. says


    I would like to replace a light bulb that hase burned out with LEDs. Is there a a base thatI can use to mount the LEDs into? This light socket in an old American Dflyermtrain engine.

    Fred B.

    • says

      If it’s a standard C7 or C9 base, then it wouldn’t be a problem to replace the bulb with a LED retrofit that has the same base. If the base is smaller, then you may have to get a more specialized LED replacement bulb from an electronic supplier such as or

  2. Matt says


    Great tips here! I am wondering how you go about spacing if you want to space every 12″ but at the end of a roof line you have 9″ left over? And with another line you have 6 inches left over.

    Not sure what the best thing to do there is.


    • says

      If you are referring to what to do with excess cord at the end of the run, you can simply cut it. If you are trying to get the bulb to end exactly at the end of the roof line, that’s not generally easy to do. Even on our professionally installed jobs, we just have the last bulb end as close to the edge as possible and then cut the excess cord.

  3. Matt says

    Thanks Jason. So if your are lighting a ridge line and the last bulb is 6″ off the edge of the roof you don’t think it would be noticeable? Even when you start down the gable end? So in this case the ridge bulb would be 6″ away from the gable end bulb though all others are spaced 12″.



    • says

      You’ll no doubt notice it every time you look at the house and you’ll think it stands out like a sore thumb. But anyone else looking at the light line won’t even see it. When you have nice straight lines and everything is done clean and neat, small areas like what you are referring to won’t even be noticeable. Good luck with your project!

  4. Kyle says

    How many 7 watt C9 bulbs can I put on one string? Not LED. I want to outline my house and it is going to take 250 ft to go all the way around. Do I need to break it up and if so, do I need to use different power outlets? Thanks.

    • says

      For C9 7 watt, we use 100 bulbs as our standard. That comes in just over 6 amps, which is 1 amp under the rating for 18 gauge C9 cord. It’s always best to be on the safe side when it comes to max number of bulbs. So for your application you would need three separate lines. For the 250 ft, you are going to be drawing about 15 amps. You could plug two of your lines into one extension cord and the other into a 3rd. All of this can go into one outlet as long as it’s at least a clean 20 amp circuit, meaning that there is nothing else on that breaker. Keep in mind that you never want to go over 80% of the capacity of the breaker. To help you know exactly how much power your lines are using, we recommend using a Kill A Watt Meter, which you can find on our site.

  5. Jordan says

    We are working to outline our new house with C9 string-a-long lights (gasp, I know) but can’t figure out the way pros jump from gable to gable or move the line from one section to another where the lights don’t need to be (example is on the picture at the top of this article, the windows near the top of the roof line… lights moving from one to the next). Do you just unscrew the un-needed lights and leave the sockets exposed or tape them up with electrical tape? Or are there plug stoppers/fillers to put in those sockets? Any tips for this would be great!!! Thanks!

    • says

      If the light line is the empty socket light line where the bulbs screw into the socket, then you can get socket caps that cover up the sockets. As an alternative, what most professional Christmas installers do is that they cut the cord, use male and female slide on plugs along with zip cord and run an extension from one section to the next. This creates a clean, professional look. But first make sure you are using 18/2 empty socket light line and not LED stringer sets. The stringer sets can not be cut.

  6. Frank says

    I just bought a house and wanted to take the plunge and create a light set instead of using the big box store lights. One thing that I haven’t been able to figure out is how do you tee off a section? It looks like you guys did that right in the middle of the example picture. Do you have to reconnect it to another section? Can you add a plug to add other features, like a wreath (provided you don’t exceed the amperage)? How could you finish a section that is just going to be exposed (as opposed to putting a plug on it)?

    • says

      You can tee off a section by using an inline female. These can be put anywhere in the line and allows for another perimeter line to be powered from the first line.

      Yes, you can plug a wreath or something else into the line by using an inline female as long as you are staying under the maximum rated load for the line.

      As far as terminating a section of cord, we typically recommend putting a female on the end so it’s a clean termination point.

      • Greg says

        If this is the end of the run and you terminate the line with a female plug is there any concern with the open plug holes in the female socket with rain, etc? Should you put something like a child proof plug to cap the end, or cover the end in electrical tape?

        • says

          Hi Greg, no the open female isn’t a big issue. There are numerous points throughout the cord, especially where the bulb and socket meet, where water can get in. Even with rubber O rings water can still get into each socket because of two drain holes at the base of each socket. So the bottom line is that C9 light line is not a sealed system and water always finds its way in.

      • Shane says

        Jason, I also need to ‘T’ from a gutter line to incorporate a roof ridge line. I noticed on your site you sell an ’18/2 SPT-1 Female Slide On Vampire Plug’ and an ’18/2 SPT-1 Female Inline Slide On Vampire Plug’, both in green. But I don’t see the variation between the two available in white.

        Are these ultimately the same plug or is there a variation between the Female Slide On and the Female ‘Inline’ Slide On? If they are different, do you offer the variation in white or do I need to go with the green versions?

        Thanks for your response.

        • says

          Hi Shane, we’ve been unable to get the inline white females. But they are the exact same as the end of the run females. You can actually take a regular female and cut a slot in the back stopper to allow the cord to pass through. A Dremel tool works perfect for this.

    • says

      In order to power up the line, you’ll need to have one male per line. If you are using empty socket light line, then simply remove one of the females and replace with a male.