C7 and C9 Bulb Information Page


C7 Bulbs      C7 Christmas lights are a classic screw in type of bulb and have a classic look that can't be beat. C7 lights are typically 5 watts and come in a variety of colors and burn types. The colors are either a Transparent color or Opaque (or Painted) colors, and these bulbs come in a Steady Burn type or Twinkle type. The base size is often called Candelabra or E12, these bulbs are the same size as what you find in a traditional night light. C7 are great for outdoor lighting for outlining a roof line on a residence, lighting a tree, or in a ground stake outlining walkways or driveways, there really is no limit to how they can be used. Since C7 bulbs are slightly lower wattage you can get more footage out of a single run when compared to C9.

C9 Bulbs      C9 Christmas lights are the larger of the two classic looking Christmas bulbs. C9 bulbs are typically 7 watts and require a little more planning when calculating the power needs and wire requirements. These larger bulbs are commonly used in outdoor lighting (even though they work fine indoors) because of their size. When you see lights outlining large buildings or very large Christmas displays you're typically seeing a C9 size christmas bulb. C9 lights come in all the same styles as a C7 bulbs, their base is referred to as either a Intermediate or E17 base. Below is a comparison of the size between C7 bulbs and C9 bulbs.
C7 and C9 Size Comparison
When using any incandescent bulb the key to a successful decorating job is knowing your limitations with power. With C7 and C9 bulbs that use a fair amount of power compared to their smaller incandescent counterparts. Most of the wire (refer to our Christmas light string page for more info) is either 7 amps or 10 amps. 1 amp is 110 watts and you shouldn't try to stretch your wire outside those power specs. Below is a quick and easy way to determine how many lights you can run, since bulb spacing on christmas light strings aren't always the same refer to your power calculations to maximize the amount of bulbs on one continuous string.

(Bulb Wattage) x (Number of Bulbs) = Total Wattage, (Total Wattage) ÷ 110 (Volts) = Amps
Example:
5 Bulb Wattage x 100 Bulbs = 500 Watts, 500 Watts ÷ 110 Volts = 4.55 Amps


Some C7 and C9 tips and tricks!
  • When lighting a tree or other greenery mix in 15% twinkle bulbs, it give the tree a little movement for a subtle and classy effect.
  • Save your boxes, reuse your product shipping boxes so your bulbs will have a safe storage box in the off season.
  • Incandescent bulbs get warm, don't let them rest on a surface that may be damaged from slight continuos heat.