Coiled DC 5521 Cable, USB-A to 5.5x2.1mm Spring

Overview

A coiled dc 5521 cable is a USB-A to DC 5.5 x 2.1 mm female adapter with a spring section in the middle. The coil absorbs the difference between the distance to the power source and the distance you actually need, retracting when the device is close and extending when it is not. On a truck dash, a forklift pillar or a test cart that gets moved around, that is the difference between a tidy installation and a loop of cable waiting to be caught.

Key Specifications

Connector A	USB Type-A male
Connector B	DC 5.5 x 2.1 mm female socket
Cable style	Coiled / spring cable
Jacket	Black PVC
Polarity	Center positive (standard)
Conductor	Stranded copper; gage stated per your drawing
Rest length	Stated per your drawing
Extended length	Stated per your drawing
Application	Truck / in-vehicle power tap, variable-distance mount

Coil against straight: what you gain and what you pay

Consideration	Coiled	Straight
Slack management	Retracts to rest length; nothing to stow	Slack has to be tied or clipped somewhere
Snag risk	Low when retracted	Loop of slack catches on anything
Effective conductor length	Long – the helix is always in circuit	Equals the route length
Voltage drop	Size for the extended length, not the rest length	Size for the actual route
Heat in a tight coil	Turns touching each other trap heat	Dissipates along the run
Cost and lead time	Higher – coiling is a second process	Lower

The fourth row is the one that catches people out. A coil that looks 30 cm long on the dash may contain a meter or more of conductor once you unwind it, and the drop is set by the conductor length, not by how far the endpoints happen to be apart. Size the gage for the fully extended condition.

Building the current budget before you order

Work it through in this order, and write the result on your drawing so we build to the same numbers you checked:

Read the current the device draws at its input, not the figure on the supply label.
Confirm what the USB-A port advertises – the host sets the ceiling.
Estimate the conductor length from the fully extended coil, doubled for the return path.
Compute the drop from the gage you intend to use, or tell us the length and load and we will size it.
Compare the drop against what the device tolerates. At 5 V the margin is thin.

We publish voltage drop guidance rather than a current table because the honest answer depends on your length and your load. Where the existing documentation does not state a figure, the value is stated per your drawing – we do not invent one.

What kills a coiled lead in a vehicle

Heat – a coil left fully extended in a sunny cab has its turns touching, so it cannot shed heat the way a straight run does.
Set – a PVC coil held stretched for months takes a permanent set and will not retract fully.
Cold – a stiff jacket in winter resists retracting and puts a pull on the plug.
Vibration – the plug takes the shaking at the socket; the strain relief has to be long enough to absorb it.
Corrosion – in a marine or humid cab, bare copper wicks corrosion up under the jacket. Tinned stranding removes that failure mode.

Typical applications for this coiled dc 5521 cable

In-cab USB power for truck drivers, where the device moves around the dash
Dash-cam installations where the camera is removed for download
Mobile routers and hotspots carried between vehicles
Test carts and service trolleys with a variable-distance power tap
Forklift and warehouse terminals mounted on an adjustable arm

How to specify your build

Rest length and extended length – both, not one.
Coil diameter and number of turns, if you already have a target.
Load current and the supply voltage.
Conductor gage, sized for the extended length.
Jacket material – standard PVC or a jacket rated for the temperature.
End style – straight or right-angle on either end.
Quantity.

Workmanship and testing

For USB A Coiled builds the line runs to IPC/WHMA-A-620 Class 3 under ISO 9001, terminating 32 to 12 AWG. Each USB unit passes a continuity and pinout check before it ships, and seal checking is quoted whenever an ingress rating is on the drawing.

Material declarations against RoHS and REACH are issued per project, alongside the dimensional and electrical reports agreed at quotation; see certifications, compliance and material declarations. Where your drawing names a UL style or another approval, the build follows your drawing and ships with the supporting document rather than a claim of our own. The strain relief and molded body are produced on tooling we cut ourselves see overmold tooling cut in our own tool room so the tool is quoted separately, owned by you, and available for repeat runs years later. Related reading: what outdoor duty does to a jacket.

Custom builds and ordering

USB A Coiled prototype lots start from 1 to 50 pcs and ship in 3 working days. Production requires 500 pcs and runs 14 working days after approval. Tooling not already held adds around 10 working days. Private-label USB runs ship under your part number and labeling, and material certificates and first-article reports are available on request.

Related DC and vehicle power assemblies

Related capability: automotive and custom harness builds.

Frequently Asked Questions

How long is the coil when it is stretched?

Whatever you specify. Rest length and extended length are both set per build – give us both numbers and the number of turns you want, or send a sample.

Does the coil reduce the current I can draw?

The gage sets the current, but you have to size it for the extended conductor length, which is longer than the coil looks. Tell us the load and we will size the conductor.

Will it stay retracted in a hot cab?

PVC can take a set if it is held stretched for long periods at temperature. If that is your installation, tell us and we will quote a jacket suited to it.