Here is a customer question we received via email today:
I need enough LED outdoor lights to light a 20 foot Colorado Spruce. How many strands can be strung together? Which ones are safe for outdoor use?
Customer Question October 25, 2020
First, all of our LED light strings or C7/C9 18 AWG Christmas light cords with LED bulbs are safe to use outside.
If you use C7 or C9 Pre-wired LED light strings, over 80 sets can be run in series. Since there can be variation in the specifications based on color, be sure to check the spec on the specific light string that has the shape, color, and spacing you are looking for.
For traditional C7/C9 bulbs and cords, the maximum length that the 18 AWG cord can be run is 250 feet in a single circuit. This is true for both low-amperage LED bulbs and higher wattage incandescent bulbs.
We suggest starting with about 300 C7 or C9 bulbs in either form of light strings for a 20 foot tree to start with. Ultimately, you'll have to gauge the weigh the width of your tree and how tight you will wind your spiral to determine a beginning estimate for your project.
Here are a few handy articles that might help you as you plan your project.