This section contains information about traditional outdoor Christmas lights: C7 Lamps and C9 Lamps plus answers to frequently asked questions about outdoor C7 and C9 Light Strings. Click on the links above if you wish to go directly to information about our new Low Energy Lamps, Hanging C7-C9 Christmas Lights, Calculating Maximum Runs and Wattage or our C7-C9 Picture Gallery.

What are C7 and C9 Lights?
C7 and C9 Outdoor Christmas Lights are larger than small mini-style Christmas lights and are often considered traditional outdoor Christmas lights. Traditional C9 and C7 Lights are heavier-duty than mini-lights and are more reliable. Christmas C7 and C9 bulbs screw into a candelabra base socket and can be replaced with standard Christmas bulbs called lamps. These "traditional" light strings are designed in such a way that if a single bulb fails, it only affects that bulb. Individuals often use C7 or C9 Light Strings to decorate large outdoor Christmas trees, outline building perimeters or simply to decorate the outside of their homes. Both C7 and C9 lamps or bulbs come in a variety of colors while the base socket and wire can be purchased in green or white.

Christmas Light Outdoor C9 Bulb

What is the differences between a C7 and C9 Outdoor Christmas Light?
The main differences between C7 and C9 Christmas lights are the bulb or lamp size, base size, and the wattage. C7 bulbs are smaller than C9 bulbs with C7 bulbs approx. 2 inches (2 1/8" to be exact from top to bottom), C9 bulbs are approx. 3" (2 7/8" top to bottom including the base). Our C7 lamps come in .6 watt LED, 2.5 watts and 5 watts while our C9 lamps are 1 watt LED, 3.5 watts and 7 watts. C-9 Lights are commonly used to decorating commercial buildings and homes over 2 stories. The C9 bulb wattage makes is slightly brighter and will stand out more on taller buildings than a C7 would.

What are the differences in the base size?
The commonly used light bulb bases in holiday lighting are candelabra base and intermediate base. A C7 bulb has the smallest base called a candelabra base and a C9 bulb has a larger base called an intermediate base. You must match up the base size to the right socket size. For example, a light bulb with a candelabra, E12 or C7 base will fit only a candelabra, E12 or C7 socket. And a C9, intermediate or E17 base bulb will only fit in a C9, intermediate or E17 base light string. Make sure when you are ordering bulbs and strands that you are matching the base size, a C7 bulb will not fit in a C9 base and vice versa.

What lengths are your C7 and C9 Outdoor Christmas Light Strings?
Our C7 and C9 Stringers are made of 18 gauge wire and come in strands of 25 Lamp Strings, 100 Lamp Strings, or 1000 Lamp Reels. Lamps are spaced 12 inches apart on our 25 and 100 Lamp Strings. On our 1000 Lamp Reel, the sockets are spaced 12, 15 or 18 inches apart. When purchasing lights, choose the spacing according to the look you want to achieve. Generally, the farther away the lights, the farther apart people want the lamp spacing. This is because the farther away the lights, the closer the spacing appears.

How do I calculate the total number of bulbs that can be run on a single circuit?
The following table gives a good idea as too the number of bulbs that can be run on a single circuit. For more details, specific formulas, and maximum light lengths go to Calculating Watts and Amps.

Total Number of C7/C9 Lamps or Light Strings Run on a Single Circuit

C7 or C9 Lamp Wattage	Lamps per 15 Amp Circuit 1800 Total Watts	Lamps per 20 Amp Circuit 2400 Total Watts	Energy Savings Compared to a 10 Watt Bulb
.6 Watts - LED C7	2400 Lamps	3200 Lamps	94% Savings
1 Watt - LED C9	1440 Lamps	1920 Lamps	90% Savings
2.5 Watts - Low Energy C7	576 Lamps	768 Lamps	75% Savings
3.7 Watts - Low Energy C9	389 Lamps	519 Lamps	63% Savings
5 Watts - Traditional C7	288 Lamps	384 Lamps	50% Savings
7 Watts - Traditional C9	205 Lamps	274 Lamps	30% Savings
10 Watts - Traditional C9.	144 Lamps	192 Lamps	0% Savings

Energy Savings

You can save on your energy bill with LED or Low Energy Lights. To calculate your savings, you need to compare the LED or Low Energy watts to the incandescent watts. You can use the following formula to calculate savings:

Lower Watt Bulb / Higher Watt Bulb. Change to % and Subtract from 100% = Energy Savings

For example, if you use LED C9 Lamps, 1 watt each, instead of C9 Traditional Lamps, 7 watts each, you would divide 1 by 7 to get .14. Change to 14%. Subtract 14% from 100% to get 86%. You will have a 86% total energy savings. See chart above for wattage amounts. Remember that even though LED lights are lower wattage, they are still quite bright and are comparable to traditional lights when installed facing outward (towards you) or down so that the light is not lost to the sky. The more LED's inside the bulb the brighter the bulb. Our C9 LED's have 5 diodes inside and the C7 bulbs have 3. Some hardware stores LED's have less diodes inside which accounts for why they look so dim.

How many sets of C7 or C9 Outdoor Christmas Light Strings can I plug in together?
When using C7 or C9 25-Lamp Strings, per UL ratings you should not connect more than three strings in a row. You can connect two of our C7 or C9 100-Lamp Strings together IF you use a 3 Outlet Power Adaptor plug in between the two light strings (plug the 3 way power outlet into the power source and have one 100FT strand going one direction, the other going out from the power outlet in the other direction). You should never connect 100-Lamp Strings together end to end unless you are using LED bulbs.

Can I plug a C7 Lamp String into a C9 Lamp String? What if they are the same wattage?
No. You should not mix the two types of strings, even if they are the same wattage.

Can I connect C7 or C9 bulbs that have different watts?
No. You should not connect stringers that contain differing watts of C7 or C9 bulbs.

Why are some of my outdoor traditional Christmas lights brighter than others?
Several factors can effect the brightness or look of our lamp. Different watts produce different brightness. Generally the higher the watts, the brighter the bulb. One exception to that rule is our High-Efficiency/Low Energy Bulbs. Traditional Incandescent C7 and C9 Christmas Bulbs can have either a double dipped or triple dipped coating of color. The less a lamp is dipped, the brighter the bulb. Age can effect the color of a lamp. Lamps that have weathered a season outdoors usually have lost some of their protective coating and as a result, they appear brighter than freshly dipped lamps. To have the most consistent look, you want to use lamps that are the same age, same wattage, and have been dipped the same number of times.