EL wire

image source: wikimedia commons

EL wire (electroluminescent wire) glows when an alternating current is passed through it. Unlike LED strips, EL wire is not a series of light points, but an unbroken line of visible light. It can be used in a variety of applications, from vehicle instrument panels and safety/emergency lighting to decoration and clothing.

EL wire works with alternating current (AC) and thus requires a driver, aka an inverter, in order to convert the batteries’ direct current (DC) into AC (in the range of 100V).

:: what is it exactly?
:: what for?
:: selecting an inverter
:: wiring EL wire
:: resources
:: tutorials
:: suppliers

What is it exactly?
Electroluminescence (EL) is an optical and electrical phenomenon in which a material emits light when electrical current is passed through it or when exposed to a strong electrical field.

EL wire consists of 4 or 5 concentric layers, each performing a different function. In the center is a solid copper conductor coated in phosphor, around which are wrapped two very fine conductive wires, followed by a clear protective sleeve (not present in 1.2 El wire), and a colored PVC sleeve. In some products, such as glowire, the wire is first covered in a clear PVC coating and then a layer of colored vinyl. Current flowing through both the core and the two thin copper wires creates an electrical field and causes the phosphor to glow. The outer plastic sheaths filter the light produced by the phosphor and provide protection (many phosphors are highly sensitive to moisture).

EL wire is available in several diameters, the thinnest being 1.2mm (aka angel hair) and the widest being 5mm (has UV protection, suitable for outdoor use and long term display). Larger diameters are more durable and (usually) produce a thicker glow, while the thinnest (1.2 to 1.5 mm), even though not suitable for harsh conditions or when weight is a factor, are more flexible and easier to bend and shape. The Live Wire Store has spec sheets for several diameters of EL wire.

The brightness of EL wire is roughly proportional to the frequency of the inverter used to drive it: the higher the frequency, the brighter the glow, and vice versa. It never burns out, but it does burn down. According to glowire, their EL “powered at 4000hz will retain brightness for approximately 1600 hours, while 400hz power will last over 5600 hours. Although the wire never does actually burn out, it does become dimmer.”

EL is also available in a variety of colors which are determined by the combination of the phosphor glow, frequency of the applied power, and the colored plastic layer. The spectrum produced by some types of EL wire can vary significantly with the frequency, while those that are filtered (have a colored plastic sheath) vary less. The aqua/ice blue wire is the most sensitive to frequency, and its color can be changed from deep green to deep blue by varying the frequency from 60Hz to 6Hz. The color of EL wire also depends on whether it’s lit or unlit (for example, yellow angel hair looks orange when unlit), and suppliers will usually provide images of both states.

What for?
– Illuminated fabrics and garments
– Light sculptures
– Safety and emergency lighting
– Decoration
– Anywhere where a continuous strip of light is desired :)

Selecting an inverter
Different types of inverters run on between 1.5V and 18V, depending on how much power they output. The selection of an inverter depends on the brightness desired (the higher the frequency, the brighter the wire) and the length of EL wire, i.e. the longer the strand of EL the more high power the inverter required to drive it. Suppliers will usually tell you the length range for each inverter (there’s a minimum and a maximum). So, in order to select an inverter for your project, you need to first know the length of EL wire you’ll be working with.

2xAA 1.5Vdc, 4500Hz, 0.5-2.5m (1.5′-7.5′) inverter

When using several strands of EL wire with a single inverter you should simply add the lengths of each strand and make sure the total is within the range of the inverter. For example: an inverter for 5m to 12m can be used to power a single 8m strand of EL wire or 8 x 1m strands.

El wire inverters usually make a slight humming noise, which is the audible sound of the frequency.

Wiring EL wire
Plug & Wear has two very good tutorials on how to wire EL, one using metal ferrules and the other connecting the EL wire directly to a (flexible) PCB. I’ve found that even though the PCB method can be very useful when connecting several wires to a single inverter, it’s also very fragile: after some handling the two thin copper wires tend to break and the soldering pads on the flexible PCB tend to come off. To strengthen the connection I’m currently using a combination of the two.

0 :: Materials & Tools
– EL wire
– Uninsulated ferrules
– Electrical wire
– Heat shrink tubing
– PBC (flexible or otherwise, only useful when wiring several strands of EL to a single inverter)
– Wire strippers
– Soldering iron (and solder)

1 :: Strip a piece of the PVC layer on one end of the EL wire, you’ll see two thin copper wires wrapped around the phosphor layer. If your EL wire has two plastic coatings (one clear and one colored), you’ll need to strip both in order to have access to the copper wires. I’ve found that many wire strippers are too aggressive for this job and end up cutting/damaging the thin wires. This is kind that seems to work well. Then, using a knife, scratch off a piece of the phosphor layer at the tip of the EL strand

2 :: Bend back the two thin copper wires and slide a metal, uninsulated ferrule over them and around the tip of the PVC sleeve. Crimp it and solder an electrical wire to the exterior of the ferrule.

3 :: Solder another electrical wire to the exposed copper core.

4 :: Slide the thinnest heat shrink tube over the ferrule. Shrink it by exposing it to heat (I like a hair drier since I’ve already messed up a few EL wire connections by using lighters and soldering irons). Take the widest heat shrink tube, slide it over the whole connection, and shrink it too.

5 :: If you’re wiring only one strand of EL to an inverter, skip this step and move on to the next one. If you’re connecting several strands of EL to a single inverter some kind of board will be useful. Plug & Wear offers a flexible PCB but, depending on the purpose, you can use any PCB or perfboard. Simply solder each wire coming out of the EL to a row on the board. Then solder two more electrical wires to each row, which you’ll use to connect the board to the inverter.

6 :: You now need to connect your EL wire/board to the inverter. If your inverter has an on/off button, make sure it’s off. Remove the batteries or unplug it from the wall socket. Simply put: make sure your inverter is not powered in any way before doing this.

To make a permanent connection between the EL wire/board and the inverter, start by sliding a heat shrink tube over each of the wires coming out of it. Solder each of the two electrical wires coming out of the EL wire/board to each of the two wires coming out of the inverter (there’s no polarity on EL wire). Slide the heat shrink tubes over the connections and shrink them. I like to use two layers of heat shrink or electrical tape, to make sure it’s all properly insulated.

Resources
:: Inverter comparison chart – Glowire
:: EL wire spec sheets – Live Wire Store
:: What is EL wire – Elwire.com

Tutorials
:: How to connect EL wire – Plug & Wear
:: Connecting EL tape to a PCB – Plug & Wear
:: How to terminate EL wire – Plug & Wear
:: Soldering EL wire – NeonString
:: Soldering EL wire – Live Wire Store
:: Soldering EL wire – Cool Neon
:: Make a glowing, wearable, EL-wire, blinky light using open source tools – Makezine
:: How to add EL wire to a coat or other garment – Instructables
:: How to make EL Wire Art – Instructables

Suppliers
:: CooLight (USA)
:: Cool Neon (USA)
:: Elec2Go (Australia)
:: EL wire online (Canada)
:: Farnell (UK)
:: Glow Authority (USA)
:: Glowire (USA)
:: Light by Wire (Germany)
:: Light’N Wire (USA)
:: Live Wire Store (USA)
:: MindSets (formerly MUTR) (UK)
:: NeonString (USA)
:: Plug & Wear (Italy)
:: That’s Cool Wire (USA)

Share your knowledge
If you’d like to contribute content or corrections regarding EL wire, please use the comment form below or add them directly to the openMaterials wiki:
materials/electroluminescent/EL wire

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