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A guide to extension cords & cables at Big Star Lights

This article explains when and how to use each Power Cord type, what they connect to, and best‑practice safety tips. It covers both standard SPT‑2 cords and our heavy‑duty options and accessories.

Emma Sheldon avatar
Written by Emma Sheldon
Updated over a month ago

Quick chooser

  • Need a simple plug‑in from a wall outlet to your first run of lights? Use Power Cord (15 ft).

  • Need the same but want to feed up to three standard SPT‑2 runs at once? Use Power Cord 3‑Outlet Plug (15 ft).

  • Need to bring power a long distance along SPT‑2 cord? Use the 100 ft or 1000 ft Power Cord spools and terminate as needed.

  • Need a custom length extension cord over 15ft? Use the 100 ft or 1000 ft Power Cord roll or spool, cut the cord to length, and apply zip plugs as needed.

  • Need a quick male‑to‑female jump between coaxial mini lights, coaxial garlands or wreaths? Use Coaxial Plug Extension Cord (15 ft).

  • Powering longer or higher‑load installations, trunk lines, or multiple taps? Use Heavy Duty Extension Cords or build from the Heavy Duty Power Cord (1000 ft) with the heavy‑duty plug/tap accessories.

What “SPT‑2 18 AWG” means

  • SPT‑2: Insulation thickness suited to seasonal lighting use

  • 18 AWG: the wire size typical for standard roofline and décor lighting.

  • AWG refers to American Wire Gauge, the unit of measurement for the diameter or thickness of electrical conductors.

  • 18 refers to the thickness of the wire in gauge, which equals approximately 1.02 millimetres (0.04 inches) in diameter.

  • Use cases: Low to moderate load runs

  • Always follow the rating printed on the product label and local electrical code. Do not exceed the circuit or product amp rating.

Standard SPT‑2 power cords

Power Cord (15 ft) — SKU: SPT2#18-15-G

  • Use: Connects from a standard wall outlet to your first plug in

  • Ends: Standard two-prong male plug on one end and female plug on the other

  • Typical scenarios:

    • Bring power from the home outlet to the beginning of a run of lights

    • Feed a single roofline run

  • Can be custom cut to length if a shorter length is required, compatible with SPT-2 zip plugs

Power Cord 3‑Outlet Plug (15 ft) — SKU: SPT2#18-15-3OUT-G

  • Use: Connects from a standard wall outlet to your first plug in (same as the Power Cord (15 ft) — SKU: SPT2#18-15-G), but with three SPT‑2 female outlets at one end of the cord to power up to three separate runs of lights

  • Benefits:

    • Reduces cord clutter at the origin point

  • Good for:

    • Splitting left/right/front runs

  • Can be custom cut to length if a shorter length is required, compatible with SPT-2 zip plugs

Longer options for SPT‑2 Power Cord & Custom Extension Cable

Power Cord (100 ft) — SKU: SPT2#18-HUND-G, SPT2#18-HUND-B & SPT2#18-HUND-W

  • Use: Long cord for creating custom lengths of extension cable or power cord. Designed for professional use, and should be cut to length before installing

  • Good for:

    • Creating custom lengths of extension cable

    • Can also be used to create custom light strings when combined with E12 or E17 replacement sockets

  • Compatible with SPT-2 Zip plugs. Use zip plugs to create male and female ends, or use female zip plugs as in-line plugs to create a ‘T’ shaped run.

Power Cord (1000 ft) — SKU: SPT2#18-1000-G, SPT2#18-1000-B & SPT2#18-1000-W

  • Use: Extra long cord for creating custom lengths of extension cable or power cord. Designed for professional use, and should be cut to length before installing

  • Good for:

    • Creating custom lengths of extension cable

    • Can also be used to create custom light strings when combined with E12 or E17 replacement sockets

  • Compatible with SPT-2 Zip plugs. Use zip plugs to create male and female ends, or use female zip plugs as in-line plugs to create a ‘T’ shaped run.

A note on SPT-2 Power Cord:

Power Cord (15 ft), Power Cord 3‑Outlet Plug (15 ft), Power Cord (100 ft), Power Cord (1000 ft), E17 Socket Power Cord, E17 Spool (500 ft), E17 Magnetic Spool (250 ft), E12 Socket Power Cord, and E12 Spool (500 ft) all use the same SPT-2 18 AWG base wire. This means they are all compatible with SPT-2 zip plugs. These products can all be custom cut to length if desired, although shorter lengths are sold with plugs pre-attached for convenience. All SPT-2 based wire products have a maximum recommended run of 250 ft—regardless of the number of bulbs used—because most circuit resistance comes from the wire itself. If in doubt, use a clamp meter to test the load of your installation. Keep in mind that resistance increases as wire ages.

SPT-2 Wire Termination caps are also designed for use with 18 AWG SPT-2 wire products.

Coaxial jumpers

Coaxial Plug Extension Cord (15 ft) — SKU: COAX-15-G

  • Use: Quick male-to-female coaxial extension cord for systems using BSL coaxial connectors

  • Compatible with 5mm coaxial mini lights, coaxial string light adapters, coaxial garlands, and wreaths

  • Handy for creating an unlit run between lit features in an installation, without the need for additional regular extension cables or multiple adapters

Heavy‑duty power cords and extension cables

Heavy‑duty cords are designed for higher current and more robust outdoor use, trunk feeds, and multi‑tap distributions. Pair with heavy‑duty accessories listed below.

Heavy Duty Extension Cord — SKUs:

  • EXT-HD-14AWG-15-B (15 ft, 14 AWG)

  • EXT-HD-14AWG-35-B (35 ft, 14 AWG)

  • EXT-HD-14AWG-50-B (50 ft, 14 AWG)

Use when:

  • Supplying multiple long lighting runs from a single origin

  • Runs are long and load is higher than standard SPT‑2 plugs can handle

  • You want a durable, heavy duty main feed

Notes:

  • 14 AWG cords typically support higher load than 18 AWG. Always verify the rating on the cord jacket and keep total load within the lowest‑rated component in your circut.

Heavy Duty Power Cord (1000 ft) — SKU: EXTCORD-HD-1000-G

  • Use: Bulk heavy‑duty cable for building custom heavy‑duty leads and trunk lines

  • Pair with:

    • Heavy Duty 3 Outlet Power Tap — SKU: HD-TAP-B

    • 3‑Wire Plug (Female) — SKU: HD-PLUG-FEMALE-1PC

    • 3‑Wire Plug (Male) — SKU: HD-PLUG-MALE-1PC

Compatibility reminder:

  • Use heavy‑duty cords and taps for upstream distribution

  • Transition to SPT‑2 near the actual light runs if needed, using appropriate adapters and respecting load limits

Choosing the right cord

  • Distance to first light:

    • Short (under ~15 ft): Power Cord (15 ft) or 3‑Outlet variant

    • Medium to long: Power Cord (100 ft) or Heavy Duty Extension Cord

    • Very long with multiple feed points: Heavy Duty Power Cord (15, 35, 50 or 1000 ft) with taps

  • Load and robustness:

    • Typical roofline: SPT‑2 18 AWG

  • Connector type in your system:

    • SPT‑2 ecosystems: SPT‑2 cords and vampire fittings

    • Coaxial ecosystems: COAX‑15‑G jumpers for quick connects

Best practices and safety

  • Respect the lowest‑rated component: cord, tap, plug, device, timer, or breaker

  • Keep connections off the ground and drip‑looped to shed water

  • Use GFCI‑protected outlets outdoors

SKUs reference

  • SPT‑2 cords:

    • SPT2#18-15-G

    • SPT2#18-15-3OUT-G

    • SPT2#18-HUND-G

    • SPT2#18-1000-G

  • Coax:

    • COAX-15-G

  • Heavy‑duty cords and parts:

    • EXT-HD-14AWG-15-B

    • EXT-HD-14AWG-35-B

    • EXT-HD-14AWG-50-B

    • EXTCORD-HD-1000-G

    • HD-TAP-B

    • HD-PLUG-FEMALE-1PC

    • HD-PLUG-MALE-1PC

Related Articles
Guide to installing roofline lights
A Guide to Big Star Lights Wreaths and Garlands
Which Lights to Use for Canopy, Trunk & Branch Wrapping
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