String Light Span Calculator for Campers

The string light installation is treated structuraly, not decoratively.

Wrapping them around the awning and plugging them in resulted in a chaotic drooping mess; instead, you need to consider geometry. The lights act as a temporary bridge across span and must be held up and pulled tight. If you don’t think about this span, you gets a chaotic mess. Get the span right, and you’ve got yourself a cozy patio.

How to Install String Lights

Sag is the primary problem. Because there’s weight to the wire, physics says it will sag between anchor point. Clamping the wire too hard doesn’t get rid of the sag. Pulling it to hard makes the wire stretch or causes bulbs to pop out. Leave it slack and lights sag. That’s where this calculator comes in.

It does the math for you. It takes what you want the finished product to look like and turns those desires into specific measurements (of both support spacing and cord length). It allows you to buy just enough wire, taking guessing game out of it.

First determine what you want to outline. Account for the corners if you are framing a canopy. Run down both sides. Add them together. That’s the total length of the run. Or, measure from end to end if it’s a straight run. If it’s an L shaped patio, add those two ends.

When running lights up a fence line most folks don’t account for return trip. When outlining a canopy they neglect the corners. Enter all that into tool and let it do the math.

Next decide how much sag you desire. Six percent is tight. Ten percent gives you a nice soft curve. A twenty foot span with a ten percent dip means a 2′ dip. Most folks look for a six to ten percent sag. You’ll find your sweet spot somewhere in there.

Another important variable is how far apart those supports are spaced. No, they can’t be the ends and then hope for the best. They’ll need intermediate help because weight of the bulbs has to get pulled up by something. G40 globes is heavy, lots of weight per foot of length. Enter the support calculator, which will estimate how many clips you would of needed if you went with your max unsupported distance. With all that weight, you want to keep them every three to four feet so string doesn’t sag under load.

If you go further than fifteen feet between trees, you adds a separate guide wire. Run it tight, let the lights hang off it. The lights’ only job is to provide the glow; the cable carries the structural stress.

The last limitation is power. Most RV outlets are limited to about six hundred watts per circuit. If you daisy-chain several strand together, you must understand the combined load. Here’s where LEDs help because each bulb pulls one to two watts. That means you can string dozens of them and never trip the breaker. By contrast, an incandescent bulb draw ten watts or more. That’s enough to trip a breaker with just ten bulbs on a single outlet.

With the calculator, it monitors your load (in watts) compared to limit of your outlet. If you’re pushing too hard, it warns you. You don’t leave until you know. Dimming out the microwave? No way.

Then you tack on slack. For RVs, eight percent is a good rule of thumb. That’s the amount needed to neatly follow rails with the wiring. It’s enough for a nice turn around post and at plug end.

A clean run looks professional. Tangling and loose ends look like they was rushed.

Once you get your figures, order a bit more wire. It’s better to cut back a line of lights than try to splice one together in the breeze.

And you think about the geometry and take into account weight. You calculate the watts. Then when the sun sets, you appreciate the light.