How many gilbert (vampire) plugs do I need to order?

January 20, 2021

Gilbert plugs are part of many of our Get This Look materials lists. They are required when custom C7/C9 cords made with 18 SPT-1 or SPT-2 lamp cord style cords are “cut to fit”.

Short Answer: These plugs work ONLY with a C7 or C9 traditional parallel-wired cord like the cords in this category. They are not meant for 2 or 3-wiring harness Christmas mini lights strings. You’ll need to order one male plug for each place where your custom cords need to be plugged in and a female plug for each place where you need to join a set with an extension wire or for terminating a cord at the end of the wire.

Long Answer.

First, the question should be: Do I need vampire plugs at all?

If you have purchased 50 or 100-foot cords and don’t plan to cut them or plug in sections cut from them, you don’t need to purchase additional plugs.

Otherwise, to answer that question, take the following steps in planning your project with an eye on where you’ll need plugs:

  1. Make a plan for your Christmas lights installation. Sketch everything out. A printed black and white photo can help with this initial step.
  2. Note where each outlet is located.
  3. Common sense electrical tip: Make sure no single run of 18 AWG cord is cut longer than 250 feet. Consult with an electrician if you have any questions about the maximum ratings of household breakers.
  4. Strategically decide how each part of the installation involving the lamp cord strings will be installed and where it will be powered.
  5. Order a male gilbert (vampire) plug for each location that requires plugging into an outlet. Order a couple of extra plugs for good measure so a miscalculation doesn’t delay installation. Order female plug ends to terminate the ends of the cords if you don’t plan to wrap then in electrical tape or dip them in liquid electrical tape.
  6. Determine if you’ll be using bulk lamp cord to create small custom “extension wires” to span spaces between eaves or windows. Both a male and a female plug will be required to create these socket-free “mini cords”.
  7. Note any T configurations required in the plan layout and order easy to install inline gilbert plugs for each intersection.

This video shows how easy it is to install a gilbert plug. Make sure that all the plugs are installed on the same side of the cords to keep them electrically uniform.

More common sense notes:

Most 25-foot cords are made with 20 AWG wiring and come with a male and female plug set so you can plug a maximum of two strings end-to-end in a single run. They don’t work with the style of gilbert/vampire plugs featured in this post.

Make sure to choose plugs that are either SPT-1 or SPT-2 and that this specification matches the cord. If in doubt and there is no labeling on the cord, chances are, the cord is standard SPT-1.

50-foot and 100-foot cords are made with a single male plug. Order female plugs if the installation plan requires it.

Spools of 500, and 1000-foot spools cannot be plugged in without cutting them into shorter, sections. Do not install a plug and plug the entire cord into an outlet. This would be electrically unsafe. Consult with an electrician if there are any questions regarding maximum light line lengths.

Lastly, always order a couple of extra plugs to make sure installation won’t be delayed by the shortage of a single plug.

Christmas Light Source Design Team
We are always on the lookout for new and interesting ways to make all of life's occasions brighter. Always ready with lighting tips, tricks, and easy projects. Join us often as we bring projects from our design lab, share customer projects, and look forward to Christmas all year long.

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