What Is a Curly Cord?

A curly cord is a flexible electrical cable formed into a tight helical spiral that stretches when you pull it and springs back to its compact coiled shape when released. If you have ever picked up a landline telephone, used a power tool tethered to a workbench, or seen a spiraling cable dangling from a truck's air brake system, you have encountered a curly cord in action.

The term "curly cord" is the everyday, colloquial name for what the electrical and manufacturing industries formally call a retractile cord or coil cord. You will also hear people refer to curly wire, curly cable, or curly cord cable — these all describe the same product. The names vary by region, industry, and habit, but the underlying technology is identical: a cord engineered with permanent spring memory so it can extend to several times its resting length and retract without tangling, kinking, or losing its shape.

At Autac USA, we have been manufacturing curly cords — retractile cords, coil cords, whatever you prefer to call them — in North Branford, Connecticut since 1947. As a 100% woman-owned manufacturer, we produce over 400 standard configurations and build custom curly cords to exact customer specifications. This guide draws on nearly eight decades of manufacturing expertise to explain what curly cords are, how they are made, and how to select the right one for your application.

Why So Many Names for the Same Product?

The variety of names for curly cords reflects how different groups of people interact with the product. End users — the people who plug in a telephone handset or stretch a cord across a workbench — naturally describe the product by its most obvious physical characteristic: it is curly. Hence curly cord, curly wire, and curly cable.

Engineers and procurement professionals tend to use more technical terminology. Retractile cord is the UL (Underwriters Laboratories) standard term and appears in product specifications, safety certifications, and compliance documentation. Coil cord or coiled cord is the most common industry trade name and is what you will find in most manufacturer catalogs, including ours.

Here is a quick reference for the terminology:

Term Who Uses It Context
Curly cord General public, end users Everyday conversation, online searches
Curly wire / curly cable Consumers, DIY community Product searches, informal descriptions
Retractile cord Engineers, UL, regulatory bodies Specifications, safety certifications, code compliance
Coil cord / coiled cord Manufacturers, distributors, OEMs Product catalogs, purchase orders, trade publications
Spiral cord European markets, automotive industry International specifications, trailer/vehicle connections

Regardless of the name, the product is the same. If you are searching for a curly cord, you are looking for a retractile cord — and you have come to the right place.

How the Curly Shape Is Created

A curly cord does not start out curly. It begins as a straight length of insulated electrical cable — copper conductors surrounded by insulation and an outer jacket — identical in construction to any conventional cord. The helical shape is added through a precision manufacturing process that gives the jacket material permanent spring memory.

The process works like this:

  1. Winding. Straight cord stock is wound tightly around a cylindrical steel mandrel (a precision rod or tube) at a controlled pitch — the distance between each coil turn. The pitch determines the cord's outer diameter and how tightly packed the coils are.
  2. Heat setting. The mandrel with the wound cord is placed in an oven and heated to a specific temperature for a precise duration. The exact temperature and time depend on the jacket material. This heat-curing process restructures the thermoplastic or thermoset molecules in the jacket, permanently "setting" the helical shape at a molecular level.
  3. Cooling and removal. After the heat cycle completes, the cord cools on the mandrel. Once cooled, the cord is removed and it holds its coiled shape independently. It now "remembers" the helix and will return to it after being stretched.
  4. Termination. The straight sections at each end of the cord — called tangent leads or simply leads — are left uncoiled to provide strain relief and connection points for plugs, connectors, or bare wire ends.

The quality of this heat-setting process is what separates a curly cord that maintains its shape over tens of thousands of extension cycles from a cheap cord that sags, stretches out, and refuses to retract after a few months of use. At Autac, we have refined our heat-set formulas over decades for each jacket compound we offer, ensuring that every curly cord we ship delivers consistent retractile performance throughout its service life.

Types of Curly Cords

Curly cords are not a single product — they are a category that spans a wide range of electrical ratings, conductor configurations, and jacket materials. Here are the main types:

Power Curly Cords

These are curly cords designed to carry AC line voltage to power tools, equipment, and appliances. They are built with heavier gauge conductors (typically 10 to 18 AWG) and UL-listed jacket types. Common cord designations include SJT (Service Junior Thermoplastic) for light-to-medium indoor duty at 300V, SJTO for oil-resistant indoor environments, SO (Service Oil-resistant) for heavy-duty industrial use at 600V, and SOW for outdoor and wet-location applications. A power curly cord is what most people picture when they hear the term: a robust spiraling cable with a plug on one end and a connector on the other.

Communication Curly Cords

The telephone handset cord is the original and most iconic curly cord. But communication-type curly cords extend far beyond telephones. This category includes cords for dispatch microphones, intercom systems, headsets, PLC (programmable logic controller) connections, and sensor leads. These cords use finer gauge conductors (typically 22 to 26 AWG) and may have anywhere from 2 to 25 or more conductors to carry voice, data, and control signals simultaneously.

Shielded Curly Cords

When electromagnetic interference (EMI) is a concern, curly cords can be manufactured with braided or spiral shield layers beneath the outer jacket. Shielded curly cable is essential in medical settings (where interference can compromise patient monitoring), audio and video production (where signal noise is unacceptable), and industrial automation (where motors and drives generate electromagnetic fields). The shielding adds some bulk and reduces flexibility slightly, but it preserves signal integrity in electrically noisy environments.

Miniature Curly Cords

Not every application needs a heavy-duty curly cord. Miniature curly cords use small-diameter conductors (22 to 26 AWG) and thin jackets to produce a compact, lightweight coil ideal for handheld devices, barcode scanners, test probes, portable instrumentation, and wearable technology. These cords prioritize minimal size and weight while still delivering reliable retractile performance.

Multi-Conductor Curly Cords

Standard power curly cords have 2 or 3 conductors. But many industrial and communication applications require 4, 6, 8, 12, or even more conductors bundled into a single curly cable. Multi-conductor curly cords consolidate multiple signal and power pathways into one retractile assembly, reducing cable clutter and simplifying installations on equipment like pendant controllers, robotic arms, and dispatch consoles.

Where Curly Cords Are Used

The self-managing, retractile nature of curly cords makes them valuable anywhere a cable needs to extend to a working distance and retract when not in use. Here is where you will find them across industries:

Telecommunications and Office

The telephone handset curly cord is how most people first encounter this product. But office environments also use curly cords for headsets, conference phones, desk-mounted USB and data cables, and point-of-sale scanners. The cord keeps the desk organized, extends when needed, and retracts to a tidy coil when the device is set down.

Healthcare and Medical Devices

Hospitals rely on curly cords for patient monitors, infusion pumps, nurse call systems, diagnostic devices, and surgical instruments. In patient care areas, a retractile curly cord eliminates the trip hazard of a straight cable draped across a floor. Shielded curly cords protect sensitive medical instrument signals from interference caused by nearby imaging equipment, motors, and other electronics.

Manufacturing and Assembly

On factory floors and assembly lines, curly cords connect handheld power tools, torque wrenches, pneumatic controllers, and barcode scanners to fixed workstations. The cord extends to wherever the operator needs to work and retracts automatically when the tool is set down, keeping the cord out of moving machinery, off conveyor paths, and clear of foot traffic. Heavy-duty curly cords in SOW jackets handle the abrasion, oil exposure, and mechanical stress of industrial environments.

Automotive and Transportation

Curly cords connect tractors to trailers for air brake systems, ABS signals, and lighting circuits. The curly cord cable bridges the articulation gap between a truck cab and its trailer, stretching as the vehicle turns and retracting as it straightens. Automotive diagnostic tools and handheld scanners also use curly cords to reach around a vehicle without excess cable pooling on the shop floor.

Retail and Point of Sale

Barcode scanners, payment terminals, customer-facing displays, and receipt printers at checkout counters are frequently connected with curly cords. A cashier pulls the scanner to read an item and the cord retracts when the scanner returns to its holder. Miniature curly cords work well here, keeping counter space clean without adding bulk.

Audio, Video, and Broadcasting

Studio headphones, microphones, and camera tethers often use curly cords to give operators freedom of movement while keeping cables manageable. Shielded curly cable prevents the signal degradation that straight cables are equally susceptible to but that becomes more problematic when cables are loosely coiled and bundled near power lines and other interference sources.

Military and Government

Communication headsets, radio handsets, and field equipment in military applications use ruggedized curly cords built to withstand extreme temperatures, moisture, abrasion, and chemical exposure. These cords are typically manufactured to MIL-SPEC or custom specifications with specialized jacket compounds and connector configurations.

Materials and Specifications

Choosing the right curly cord starts with understanding the materials and ratings that define its performance. Here are the key specifications:

Jacket Materials

Wire Gauge and Current Capacity

Wire gauge determines how much current a curly cord can safely carry. Heavier gauges (lower AWG numbers) carry more current but produce a stiffer, heavier coil. Lighter gauges (higher AWG numbers) create more flexible, compact curly cords suited to low-power signal applications.

Wire Gauge (AWG) Typical Amperage Common Use
10 AWG 30A Heavy industrial tools, high-draw equipment
12 AWG 20A Power tools, industrial machinery
14 AWG 15A Workshop tools, medical devices
16 AWG 13A Light-duty power, small appliances
18 AWG 10A Low-draw devices, lamps, chargers
22–26 AWG Signal-level Communication, data, sensors, control circuits

Retracted and Extended Length

Most curly cords follow an approximate 5:1 extension ratio. A cord with a 2-foot retracted length extends to roughly 10 feet. A 6-foot retracted cord reaches approximately 30 feet. The tangent leads (straight sections at each end) typically add 6 to 12 inches per side, providing strain relief at the connection points. When sizing a curly cord, measure your maximum working distance, divide by 5, and that gives you the approximate retracted coil length you need.

Voltage and Safety Ratings

Power curly cords are rated at either 300V (SJT-type, suitable for indoor commercial use) or 600V (SO/SOW-type, suitable for industrial and outdoor use). UL listing certifies that a curly cord has been independently tested for electrical safety, insulation integrity, flame resistance, and mechanical durability. For any commercial or industrial installation, always specify UL-listed curly cords — it is typically required by building codes, OSHA regulations, and insurance policies.

How to Choose the Right Curly Cord

With hundreds of possible configurations, selecting the right curly cord comes down to answering a series of practical questions about your application:

  1. What are you connecting? Identify the device's voltage, amperage, and wattage requirements. This determines the minimum wire gauge and cord type you need. A 15-amp power tool requires at least 14 AWG; a telephone handset needs only 26 AWG.
  2. How far does it need to reach? Measure the maximum distance from the power source or connection point to where the device will be used. Divide by 5 to estimate the retracted coil length, then confirm that the total extended length (coil plus tangent leads) covers your working distance with some margin.
  3. What is the environment? Indoor, climate-controlled spaces allow PVC-jacketed curly cords. Outdoor use, oil exposure, extreme temperatures, or chemical contact calls for neoprene, Auta-Prene, or TPE jackets. Wet locations require a "W" rating (SOW).
  4. Do you need shielding? If the curly cord will be used near motors, drives, RF equipment, or other EMI sources — or if it carries sensitive signals for medical, audio, or data applications — specify shielded construction.
  5. How many conductors? Standard power cords have 2 or 3 conductors. Communication, control, and multi-signal applications may require 4 to 25+ conductors. Count every signal and power pathway you need in the curly cable.
  6. What connectors do you need? Curly cords can be terminated with standard NEMA plugs, IEC connectors, modular jacks, circular connectors, or stripped and tinned bare leads. Specify the connector type for each end.
  7. Stock or custom? Autac's catalog includes over 400 standard curly cord configurations covering the most common combinations of gauge, conductor count, length, jacket material, and termination. If your application falls outside the standard catalog, our engineering team designs and manufactures custom curly cords to your exact specifications — no minimum order quantity requirements for many configurations.

Why Buy Curly Cords from a Manufacturer?

When you purchase curly cords from Autac USA, you are buying directly from the company that engineers and manufactures the product. This matters for several reasons:

Whether you call them curly cords, curly wire, curly cable, retractile cords, or coil cords, we make them all — and we have been doing it longer than anyone else in the industry.