What socket wire is
Socket wire, also called stringer or spool wire, is two-conductor cord with empty bulb sockets molded onto it at a fixed spacing. It comes on long bulk spools. You cut a length that matches one section of roof, attach a male plug at the power end, add a female plug at the far end if another run will connect to it, and screw a bulb into every socket. The result is a run that is exactly as long as the roofline it lights.
At Christmas Light Supplier, 1,000 foot C9 socket wire spools are listed by spacing:
| Spool | Listed price | Per foot |
|---|---|---|
| C9 1,000 ft spool, 12 in spacing | $275.00 | $0.275 |
| C9 1,000 ft spool, 15 in spacing | $240.00 | $0.240 |
| C9 1,000 ft spool, 24 in spacing | $289.00 | $0.289 |
| Magnetic socket spool, 500 ft (12 or 15 in) | $503.00 | $1.006 |
The magnetic spool has magnets built into the sockets for attaching directly to metal surfaces such as steel gutters, metal fascia and storefront frames, with no separate clip. It is offered in green or black wire.
SPT-1 vs SPT-2
SPT stands for service parallel thermoplastic, the flat two-conductor cord style used for lamp cords and holiday lighting. The number describes the thickness of the insulation jacket. SPT-1 has a thinner jacket and SPT-2 a thicker one. Both are commonly made with 18 gauge conductors for this kind of use, so the copper inside can be the same while the overall cord is a different size.
| SPT-1 | SPT-2 | |
|---|---|---|
| Jacket | Thinner | Thicker |
| Flexibility | More flexible, lighter on a spool | Stiffer, heavier |
| Abrasion resistance | Good for rooflines kept off traffic | Better where cords are walked on or dragged |
| Plug fit | Needs SPT-1 sized plugs | Needs SPT-2 sized plugs |
The practical point is plug matching. Quick-connect zip plugs pierce the jacket with prongs and clamp onto the cord. A plug sized for SPT-1 will not close properly on the thicker SPT-2 jacket, and an SPT-2 plug may not make reliable contact on thinner SPT-1 cord. Always confirm the wire type on the spool or listing before ordering plugs, and keep plugs from the same system as your wire.
Lamp cord for extensions and jumpers
Runs rarely start right next to an outlet. The gap between the outlet and the first socket, and between two separate sections of roof, is bridged with plain zip cord. The lamp cord spool is listed at $78.00 for 250 feet of SPT-1 18/2 cord, rated 8 amps or 960 watts on its listing, for custom extensions and jumpers between roof sections. Using matching cord for leads and jumpers keeps the connection hardware consistent across the whole display.
Plugs
| Plug | Listed price | Per plug |
|---|---|---|
| Male plugs, 50 pack | $37.99 | $0.76 |
| Female plugs, 50 pack | $37.99 | $0.76 |
| Male plugs, 1,000 case | $699.00 | $0.70 |
| Female plugs, 1,000 case | $699.00 | $0.70 |
Each run needs one male plug at the power end. A female plug goes on the far end only if you will plug another run or a jumper into it. Plan one of each per run plus a handful of spares, since a plug is occasionally installed crooked and has to be replaced.
How to build a run
- Measure the roofline section and decide where the power enters.
- Unspool wire along the section and cut it midway between two sockets so there is a short tail at each end.
- Open a male plug, lay the cord in with the ribbed conductor oriented as the plug instructions show, and press it closed.
- Add a female plug to the far end if the run will continue.
- Clip the wire to the roof, then screw in bulbs and test before moving on.
Spare sockets happen: a socket can be cracked by a ladder or a hail storm. C9 replacement sockets are listed at $10.99 for 10, which is less than recutting a whole run.
Wire, plugs and cord in one order. Christmas Light Supplier sells socket wire spools, plugs and lamp cord at the prices above. Christmas Light Supplier ships every order free, the same day it is placed, with no order minimum and no added fees.