Classic Opaque C9 Christmas House Outline

We love this traditional Christmas display. The homeowner used glass opaque C9 bulbs installed in standard 12-inch green cords to create a bold, colorful outline around the house.

With a few shingle clips, a couple of plugs, and a little planning, this classic look is surprisingly straightforward to recreate.

Materials

• 2 cords C9 100-foot cords, green wire, 12-inch spacing – each cord includes one male plug. Add Gilbert plugs if you need to customize lengths.
• 225 bulbs opaque C9 bulbs – the project shown uses multicolor bulbs, but any solid color or custom color pattern works beautifully. The multicolor boxes contain five each of white, red, orange, blue, and green. Consider ordering an extra box of bulbs for replacements any time you’re working with glass.
• 1–3 green male SPT-1 plugs (optional) – handy for adding custom start/end points.
• 200 shingle clips – choose your favorite clip style to secure the bulbs along the roofline.

For help planning your layout and cord lengths, see our guide on measuring your home for Christmas lights.

Installation FAQs

Are the bulbs installed in a cord when they arrive?

No. To allow for maximum customization, we sell bulbs and cords separately. That lets you choose your own cord color, spacing, and length and create patterns that fit your exact roofline.

If you already have existing C7 or C9 cords that are in good condition and properly rated, you can often use those as well—just be sure the socket size, wire type, and voltage match the bulbs you’re installing. When in doubt, consult a licensed electrician.

How do I terminate a cut 18 AWG C9 cord?

Anytime you cut a cord, you need to safely cover and protect the end. Common approaches include:

• Finishing the cut end with a female plug
• Sealing the end with liquid electrical tape
• Wrapping carefully with electrical tape, ensuring no copper is exposed

Always follow local electrical codes and, if you’re unsure, ask a licensed electrician for the safest method for your installation.

Can I mix LED and glass incandescent bulbs on the same C7 or C9 cord?

Yes—if you’re using a parallel-wired C7 or C9 cord (standard commercial-style cords), you can mix LED and glass incandescent bulbs on the same run. Each socket has its own path to power, so one bulb type doesn’t depend on another.

That said, most folks prefer to keep each run either all-LED or all-glass for a consistent look and brightness. If you do mix, stay within the wattage limits of the cord and the circuit, and avoid using LEDs in series-wired mini light strings designed only for a specific bulb type.

Originally published 12/7/2020. Updated for clarity and additional FAQs.