The “Impossible” Single Wire PoE Extender: How Enable-IT and Liquid Robotics Put Tesla's Principle to Work in the Open Ocean
Every engineering company collects a certain kind of phone call. The one that starts with a long pause, and then: “We’ve been told what we need is impossible. You’re our last call.”
In May of 2018, that call came to Enable-IT from Liquid Robotics — the pioneering maker of the WaveRider and WaveGlider, the world’s leading wave- and solar-powered autonomous ocean robot. Their machines were already redefining what unmanned systems could do at sea: months-long missions, no fuel, no crew, harvesting the ocean’s own motion for propulsion while collecting and relaying data across thousands of miles of open water.
But inside those remarkable vehicles sat a networking problem that had defeated everyone who touched it. Their engineers had asked the industry’s biggest names. They’d been told, flatly, that it couldn’t be done.
They needed Power over Ethernet — data and power — delivered over a single physical wire. The world’s first Single Wire PoE Extender
Not a single pair. Not coax with its center conductor and shield. One solitary conductor. Every PoE architecture on Earth assumed at least two physical paths to complete an electrical circuit. Physics, the naysayers said, had voted. Case closed.
We took on this challenge and the project.
The Problem: Every Wire Is Weight, and Every Circuit Needs a Return Path
To understand why this specification existed at all, you have to understand the brutal engineering economics of an autonomous ocean vehicle.
A Wave Glider survives on an energy and weight budget that makes aerospace design look indulgent. The vehicle is really two vehicles: a solar-paneled surface float and a submerged, winged glider, connected by an umbilical that transmits everything the pair must share — through an environment that corrodes, fatigues, and flexes that tether with every single wave, millions of cycles per mission. Every conductor in that umbilical costs weight, drag, complexity, and another potential failure point. Reducing a multi-conductor Ethernet run down to almost nothing wasn’t a nice-to-have. It was a design requirement with mission endurance riding on it.
And the specification Liquid Robotics handed us made “almost nothing” literal: the link had to live inside the existing umbilical, over hair-thin .30 gauge conductor — wire so fine most engineers wouldn’t trust it to carry a doorbell signal — while delivering a full 100Mbps LAN with PoE between the surface float and the undersea glider. And the electronics on each end had to shrink to match: a micro-installation PCB form factor, fed directly from the vehicle’s battery DC supply through a micro connector, sipping just 150mA at 24V — 3.6 watts per board.
And there sat the impossibility: electricity flows in circuits. Current that travels down a wire to a device must return. Standard Ethernet uses pairs. PoE uses pairs. Even the crudest power delivery uses two conductors. Remove the return wire, and you haven’t simplified the circuit — you’ve eliminated it.
Unless the return path isn’t a wire at all.
The Insight: Tesla Was Right, and Sailors Prove It Every Day
More than a century ago, Nikola Tesla demonstrated single-wire electrical transmission — power delivered over one conductor, with the earth itself completing the circuit. The principle was sound; the world simply moved on to two-wire systems and filed Tesla’s approach under historical curiosity.
But one community never stopped using the planet as a conductor: blue-water sailors running HF ham radios. Every ocean-going sailboat with a marine SSB transceiver knows the technique — you don’t drag a wire back to shore to complete your antenna’s ground plane. You bond to the sea. Seawater, rich in dissolved salts, is a magnificent electrical conductor — orders of magnitude better than soil — and the ocean is the largest ground plane on the planet. Sailors have trusted their long-range communications, and their lives, to it for generations.
Our engineers looked at the Wave Glider’s operating environment and saw what everyone else had missed: this “impossible” single-wire problem came pre-packaged with the best natural return path on Earth. The vehicle doesn’t just operate near seawater. It lives in it, permanently, surrounded by an effectively infinite conductive medium.
One wire carries the PoE signal and power. The ocean itself — coupled through the vehicle’s seawater ground — completes the circuit. Tesla’s principle, proven again.
The Engineering: From Principle to Product
Having the insight is one afternoon. Making it a professional-grade, mission-deployable product is where an OEM earns its keep — and this is precisely the work our US-based custom OEM engineering team exists to do.
Turning seawater-return PoE into reality meant solving the problems the principle alone doesn’t answer. Stable power delivery and full 100Mbps Ethernet signaling over a single hair-thin .30 gauge conductor, where every conventional PoE assumption about wire resistance and voltage drop collapses. The electrochemical realities of a saltwater ground interface, where galvanic corrosion eats unprepared metals for breakfast. Signal integrity through the electrically noisy, constantly flexing environment of a vehicle powered by ocean waves. And a custom PoE Extender PCB engineered from a clean sheet for micro installation — a matched pair of boards, one surface-side and one undersea, each drawing a miserly 3.6W from the vehicle’s battery bus, small enough to disappear into a platform where every cubic centimeter and every milliamp is spoken for. All of it engineered and built to the same AS9100D aerospace-certified quality standards we apply to everything that leaves our USA factory floor.
Contemplate that power figure for a moment. Most PoE conversations on this blog involve budgeting 90, 120, or 150 watts for hungry devices at the far end of long runs. This project lived at the opposite extreme of the discipline: an entire networked power-and-data link — both ends — operating on less energy than a night-light. Power budget mastery cuts in both directions, and the same engineering team delivers both.
Design, prototyping, testing, and fabrication — all under one American roof, working directly with Liquid Robotics’ engineers, iterating in days rather than quarters. No offshore design bureau. No 5,000-unit minimum before anyone would take the meeting. Just the seminal inventors of the PoE Extender category doing what we’ve done since 1999: extending Ethernet beyond limits everyone else accepts.
The result: the world’s first PoE Extender to run on a single physical wire — data and power over one conductor, with the ocean as its return path.
The Solution at a Glance
Specification | Delivered |
Physical medium | Single hair-thin .30 gauge conductor in the existing umbilical |
Circuit return path | Seawater earth ground — the Tesla principle, marinized |
Throughput | 100Mbps LAN with PoE |
Power consumption | 150mA @ 24V — just 3.6W per board |
Form factor | Custom micro-installation PCB pair (surface + undersea) |
Power source | Direct from vehicle battery DC supply via micro connector |
Quality standard | Designed and built in Enable-IT’s AS9100D-certified USA facility |
The Receipt: Deployed Worldwide
The naysayers, remarkably, are still out there. To this day, we hear that single-wire PoE is impossible — that the physics doesn’t allow it, that no such product could exist.
Meanwhile, Wave Gliders carrying this technology have been deployed worldwide since 2025 — patrolling fisheries, monitoring hurricanes and tsunamis, supporting defense and scientific missions across every ocean on the planet, on multi-month missions with no crew, no fuel, and no second wire.
We understand the skepticism, honestly. “Impossible” is a comfortable word. It ends conversations, closes tickets, and protects reputations. But at Enable-IT, we’ve built a company — and a customer list that includes NASA, the US, UK, and Canadian militaries, and equipment operating aboard the International Space Station — on a different reflex: when the spec sheet says impossible, we hear unattempted.
What This Means for Your “Impossible” Project
Here’s the part of this story that matters to you: Liquid Robotics’ problem wasn’t unusual because it was hard. It was unusual because they refused to accept the first “no.”
Every industry has its version of the single-wire problem — the legacy wiring nobody thinks can carry modern data, the distance every vendor says can’t be reached, the environment deemed too hostile, the form factor that doesn’t exist. We’ve extended gigabit Ethernet to 9,000 feet over wiring the industry abandoned decades ago. We’ve run high-throughput links over coax, telephone pairs — even barbed wire fence. And every custom OEM engagement carries the full weight of the Undeniable Enable-IT Benefits: Designed and Made in the USA. Professional grade, trusted reliability. Industry-leading Lifetime Warranty. 45-Day Money Back Guarantee. Certified Spyware Free. No configuration — plug and go. Same-day factory-direct shipping. Next Business Day Advanced Replacement. US-based expert engineering support. And Custom USA Made OEM Solutions from 5 units to 5,000+.
The Wave Glider project began with a phone call and a problem everyone else had walked away from. Yours can begin the same way.
Bring Us Your Impossible
Whether your challenge floats on the Pacific, sits at the bottom of a mine shaft, rides an elevator cable, or hides inside a spec sheet nobody else will sign — our engineers want to hear it.
📞 Call (888) 309-0910 — Mon–Fri, 5AM–4PM PST — and put your “impossible” in front of a US-based Enable-IT design engineer.
Enable-IT: Extending secure Ethernet beyond every limit — even when the limit is the number of wires.
