Backlighting simple shapes, such as a cross, can be done simply with common rope lighting. Requiring only a basic outlet for power, these incandescent or LED-based indoor/outdoor light strands can be curved and bent (to a certain degree) to conform to nearly any shape needed. Linkable to 200 feet, the soft yet prominent lighting provided by these units is an excellent choice for backlighting displays, while not consuming an inordinate amount of power.
Access the rear of the cross. Measure the total length of the cross, including arms. Rope lighting can be extended by screwing multiple units together as needed using a supplied plastic threaded coupler, integrated in the lighting strand.
Remove the adhesive backing from the plastic zip tie anchors, pressing them into place on the rear of the cross every 4 to 6 inches, as needed. Insert at least one wood screw into the mounting holes on the anchor for a better anchor support.
Place one end of the rope lighting over the zip tie anchor, and slide the zip tie through the anchor's mounting slot. Secure the rope lighting with the zip tie, cutting off the excess tie with the small wire snips.
Continue placing the rope lighting over the anchors, securing along the way. Leave a small amount of slack in the zip ties until the placement of the lighting is ideal, then pull them tight enough to secure the lighting, but not excessively.
Screw an additional light to the existing unit (if required), and continue mounting the lighting as prescribed. Otherwise, plug in the rope light to an adjacent outlet.
Use of an extension cord for indoor use is acceptable. For outdoor applications, it is recommended that a sealed outdoor outlet be mounted in close proximity to the cross. Contact a local electrician or building inspector for advice.
If the rope lighting is bent excessively, damage to the inner filaments may occur, causing failure of one or more lighting elements.