What is that specification?

January 12, 2019

Questions about what the specifications are all about when it comes to shopping for Christmas lights?

These tables from our major lighting categories should help clear up your questions.

Light Strings (Pre-wired LED and Incandescent)

Bulb Shape: This is the shape of the bulb – the choices are C9, C7, C6, M5 (LED – looks like little icicles), G12 (small round LED), 5mm (short stubby LED circle shape like the end of a pencil), or traditional glass mini lights.

Bulb Type:  Either LED or incandescent. Be sure to double check this specification as there is a huge difference between how the light looks between the two styles.

Bulb Count: Total number of bulbs – either LED or incandescent – on the string.

Wire Color: Color of the insulation covering the wire. Choose a color to match the background of your installation.

Wire Gauge: Thickness of the wire. The smaller the number the bigger the wire.

Socket Spacing: Distance between the LED’s. The smaller lenses are generally 4 inches apart and the larger bulbs (C7 and C9) are 8 inches apart.

Bulb Diameter:  Distance around the lens of the bulbs.

Bulb Height: This is the distance from the base to the top of the lens and does not include the base measurement.

Bulb Width:  The width of the LED lens as it would be measures across with a ruler or calipers.

Connection: This answers the question of how does this light string connect. An end to end specification means that the string has a male and female plug and are run together.

Stacked or single male plug (craft lights) means that the light string has a single male plug with two holes in the top so you can plug in multiple strings at the outlet but they don’t have female connectors on the other end.

Replaceable Bulb:  Indicates whether or not the bulb in the string can be removed and replaced. For most LED light strings the answer here is no so if you need that function, be sure to check this spec. Most incandescent mini light bulbs can be replaced and extra bulbs are shipped with the strings.

Max Connection:  How many light strings can be run end to end in a single run. This is a super important specification because plugging too many lights in a row will blow their fuse.

Voltage Rating: What power source voltage the lights are rated for – on our website the choices are a standard 110/120 V or 12 V

Amperage Rating: The maximum amount of current that this light string can pull.

Amperage Usage: The amount of current the light string pulls. To calculate total amperage of a circuit, multiply this amount by the number of strings run in series not to exceed the maximum number of light strings specified.

Watts: Total power measured in watts required to operate this string of lights.

UL: Whether this light set is UL approved. (Bulbs and cords that are sold separately are not UL approved since a light string must be configured at sale to be considered for UL certification.)

Approximate total length:   Total length of light string including the wire between the plugs and first lights. This is not the total lit length. The actual length of a string of lights can vary due to twist in the wiring harness by a couple of inches. The tighter the twist the shorter the string and the looser the twist the slightly longer the string will be.

Lead length: Length of wire between male plug and first light.

Tail length: Length of wire between last plug and female plug. Note that the sum of the lead length and tail length will be the distance between the light strings when wired in series.

Bulbs (LED and Incandescent)

Bulb Shape: This is the shape and size of the bulb. C stands for “cone” in C7 and C9 and the G indicates the bulbs are round in G30, G40, and G50. See more about bulb shapes and sizes here.

Bulb Type:  Indicates whether the bulb is a traditional incandescent bulb that uses a filament to create light or a new-style LED bulb that uses a form of LED to create light.

Bulb Color: This is the color of the bulb. For LED lights, this is the color of the LED’s and the lens.

Base Type: Size of the base of the bulb. Use this specification to match the bulb to the right cord. The three sizes most likely to be seen online are E12 (the size of a C7 bulb also known as candelabra), E17 (the size of the base of a C9 bulb also known as intermdiate), and E26 (also known as medium base) which is the larger bulb base size of patio lights.

Base Finish: This is the metal that the base of the bulb is manufactured with. Most of the CLS bulbs have nickel over brass bases. Warm white LED bulbs are made with brass bases so they can be distinguished from pure white.

Bulb Diameter: The distance in mm or inches around the bulb.

Bulb Height: The height of the bulb from the top of the metal threaded base to the top of the bulb

Bulb Width: The width of the bulb from the outside to the outside. This is the distance you would measure if you put the bulb on a ruler or measured it with calipers.

Amps Usage: The amount of current that the bulb draws under operation.

Watts: Total power draw for the bulb measured in watts.

Kelvin: For LED bulbs only – and only for the SMD Bub – this specification is the range of color “temperature” of the bulb.

Lumens: An approximate measure of the brightness of the bulb at 1 meter from the bulb under operation.

Light Cords (sold without bulbs)

Wire Color: Color of the insulation on the copper wire.

SPT rating: Specification related to the thickness of the insulation. (Has nothing to do with maximum current rating, just a measure of thickness and resulting durability of the cord.) Click here to read and article comparing SPT-1 and SPT-2.

Space Between Sockets: This is the distance between sockets. Note that there can be a slight variation in the distance between sockets. Not usually a critical issue, if you are planning to install the cords on a flat roof, consider installing clips on the cord first before securing them in place and with a little “play” between the sockets to reduce stress on the cords.

Distance Between plug and first socket: The length of the wire between the male plug and first socket. For some cords, this is quite long and may help you eliminate an extension cord or two.

Distance between last socket and end of cord:  Distance between the last socket on the cord and the female plug.

Connection: This specification lets you know how many plugs are or are not installed on the cord. Most commercial C7 and C9 cords are manufactured with only male plugs. Pay close attention to this specification and order gilbert plugs for E12 and E7 cords if required for your project. All spools of cords (greater than 100 feet) will require that you purchase plugs separately.

Current Rating: Measure in amps of maximum current that the cord can pull (or use) during operation. Don’t exceed 80% of this specification.

Number of sockets: Total number of sockets on the cord or spool. This is naturally also the number of bulbs required to fill the cord. When working with glass bulbs, consider always ordering an extra box of bulbs to account for breakage during installation.

Aside from throwing dinner parties that feature at least two kinds of cheese dip, Shellie's passions include travel, Mid-Century Modern furnishings and finding the perfect street taco. Has been known to snort laugh champagne.

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