While coaxial cables are traditionally known for carrying high-frequency signals, many engineers and system integrators often ask: “Can I use a coaxial cable to transmit DC power?” The short answer is yes—but there are important limitations, use cases, and safety factors to consider.
In this guide, we’ll walk you through:
- When and how coaxial cables can be used for DC power
- Practical use cases like Power-over-Coax (PoC)
- Electrical constraints and safety limits
- Best practices and Bafitop product recommendations
How Coaxial Cables Work—and Why DC Is Not Their Primary Job
Coaxial cables are primarily designed for RF (radio frequency) signal transmission. Their core structure includes:
- A center conductor (carries signal or power)
- An insulating dielectric
- An outer conductor or shield (return path and EMI suppression)
- A protective jacket
While they’re optimized for shielding and impedance control, coaxial cables do contain conductors capable of carrying current—including DC. The question is how much, and in what context?
Yes, Coax Can Carry DC Power—Under Specific Conditions
It is possible and common to use coaxial cables to carry low-voltage DC power, as long as current requirements and distance are within reason.
Common Use Cases for DC Over Coax:
- Power over Coax (PoC): Often used in CCTV systems, allowing cameras to receive power and video over a single RG-6 or RG-59 line.
- Bias Tee Circuits: A DC voltage is injected into the coaxial line to power amplifiers or antenna devices, while the RF signal passes through.
- Remote Low-Power Devices: Sensors, preamplifiers, GPS units, and other embedded systems sometimes use coax for signal and DC power delivery.
Electrical Considerations: Resistance, Current Limits, and Voltage Drop
While coaxial cables can carry DC, they were not designed for it—so you must factor in:
- DC resistance (center conductor and shield)
- Cable length (longer cable = more voltage drop)
- Current capacity (determined by conductor diameter and heat dissipation)
Sample Comparison Table
| Cable Type | Center Conductor DC Resistance (Ω/km) | Shield DC Resistance (Ω/km) | Max Suggested DC Current |
|---|---|---|---|
| RG-59 | ~39 Ω/km | ~19 Ω/km | ~0.3–0.5 A |
| RG-6 | ~23 Ω/km | ~15 Ω/km | ~0.5–1.0 A |
| RG-11 | ~8.5 Ω/km | ~8 Ω/km | ~1.5–2.0 A |
| LMR-400 | ~3.9 Ω/km | ~3.5 Ω/km | ~2.5–4.0 A |
Always factor in voltage drop. A 12V supply may degrade to 9V at the far end on thin coax and long distances.
Practical Scenarios: When It Works—and When It Doesn’t
Suitable Scenarios:
- Supplying low-power CCTV cameras over 10–30 meters using RG-6
- Running bias power for preamps on antenna systems
- Short-run sensor nodes in embedded systems
Unsuitable Scenarios:
- High-current devices (>3A) such as motors or industrial controllers
- Long-distance DC transmission over >100 meters
- Systems where signal and power must remain electrically isolated
Best Practices for Using Coaxial Cable to Deliver DC
1. Choose a Low-Resistance Cable
Use thick-core coax like RG-11 or LMR-400 for longer runs. Thinner cables like RG-59 have high losses.
2. Shorten Cable Runs
Always keep DC paths as short as practical to minimize voltage drop and heating.
3. Proper Connector Selection
Use BNC, SMA, or F-type connectors rated for combined power/signal applications. For PoC, make sure your connector and cable are tightly coupled and grounded.
4. Consider Dual Cable Systems if Power > 2A
If your application needs high current, consider using a dedicated power line alongside coax for safety and voltage stability.
Bafitop’s Coax Cables for Signal + Power Applications
At Bafitop, we manufacture and supply a wide range of coaxial cables designed for both RF and hybrid applications. Whether you’re building a surveillance system or deploying antenna networks with bias power, we’ve got a solution.
Product Recommendation Table
| Product | Impedance | Application | Max DC Voltage | Shielding | Notes |
|---|---|---|---|---|---|
| RG-6 Quad | 75Ω | CCTV PoC, SAT, FM Antennas | ≤ 24V DC | Foil + 60% Braid | Industry-standard for video/DC |
| RG-11 | 75Ω | Long-run TV/CCTV | ≤ 36V DC | Dual Braid | Lower voltage drop |
| LMR-400 | 50Ω | RF + Bias Tee DC Injection | ≤ 48V DC | Foil + Braid | Low-loss, weather-resistant |
| RG-316 | 50Ω | GPS, Sensors | ≤ 12V DC | Single Braid | For embedded low-power devices |
All Bafitop cables are available:
- By the meter or spool
- With factory-crimped connectors (SMA, BNC, F-type, N-type)
-
In weatherproof or UV-resistant jackets for outdoor use Ask us about custom assemblies or PoC-ready kits.
Real-World Example: Power Over Coax in a CCTV System
Imagine you’re upgrading an analog surveillance system. Instead of running both a coax cable for video and a separate wire for 12V power, you could:
- Use an RG-6 Quad Shield coax
- Connect a PoC injector at the DVR end
- Power the camera and transmit video through one cable
This saves time, money, and installation complexity.
Interactive Check: Should You Use Coax for DC Power?
Answer these before deciding:
- Is your load ≤ 2A current?
- Is the total run ≤ 50 meters?
- Is the system low-voltage (≤ 48V DC)?
- Do you need to transmit signal and power together?
If you answered “yes” to all, coaxial cable may be a practical solution.
Frequently Asked Questions (FAQ)
Q1: Can coax cable carry 12V DC power safely?
Yes, for low current applications like CCTV cameras or preamps. Use RG-6 or thicker.
Q2: What’s the voltage drop over 30m of RG-59?
Approximately 2–3V at 0.5A. It’s better to use RG-6 or RG-11 to reduce drop.
Q3: Can I use RG-213 for DC power?
Yes, it’s heavy-duty and handles more current, though overkill for simple systems.
Q4: Should I use the shield or the core as ground?
Typically, the center conductor is positive, shield is DC ground—but always match your device’s polarity specs.
Q5: Is coaxial DC transmission legal or compliant?
Depends on application. It’s common in telecom and CCTV, but not for high-power industrial wiring. Check local codes.
Let Bafitop Help You Combine Power and Signal—Safely
At Bafitop, we’ve helped thousands of installers and engineers find the right coaxial solution for integrated power and signal systems. Our cables are:
- Signal-optimized and low-loss
- Rated for low-voltage DC power
- Available in UV and waterproof versions
- Compatible with SMA, F-type, BNC, N-type connectors
Need samples? Questions about voltage limits? We’re here to help.
Contact Us
Email: sales@bafitop.com
Phone: +86-15817341810
