What Size Wire Is Used for Low Voltage? A Simple Guide for Homeowners and Installers
If you’ve ever installed a security camera, doorbell, or landscape lighting system, you’ve probably asked yourself, “What size wire should I use for low voltage?” Choosing the right wire size is one of the most important parts of any low-voltage installation. The correct wire ensures safety, efficiency, and reliable performance across your entire system.
Whether you’re working on a CCTV system, alarm wiring, audio setup, or LED lighting, this guide will help you understand wire sizes, voltage drop, and how to select the best cable for your project. Our experienced low voltage wiring professionals in Los Angeles ensure that every installation uses the correct wire size and meets safety standards.
What Is Low Voltage Wiring?
Low voltage wiring typically refers to electrical systems that operate at 50 volts (V) or less. Common low-voltage applications include:
- Security camera systems (12V or 24V DC)
- Doorbells and access control systems
- Thermostats and HVAC controls
- Landscape lighting
- Speaker and audio wiring
- Ethernet and data cabling (CAT5e, CAT6)
Because these systems use less power, they require smaller gauge wires than standard 120V electrical circuits — but wire size still matters a lot.
Why Wire Size Is Important in Low Voltage Systems
The wire gauge, measured by the American Wire Gauge (AWG) standard, affects how much current a wire can carry and how much voltage is lost along the way.
If the wire is too small, it can cause:
- Voltage drop, reducing the performance of lights or cameras
- Overheating, which can damage the cable
- Intermittent power issues, especially on long runs
Using the correct wire gauge helps your devices perform properly and extends the lifespan of your equipment.
Common Wire Sizes Used for Low Voltage
Here’s a quick overview of the most common wire gauges used for low voltage wiring and their typical applications:
| Wire Gauge (AWG) | Typical Use | Recommended Max Distance (for 12V systems) |
|---|---|---|
| 22 AWG | Short runs for sensors, thermostats, and data | Up to 40 ft |
| 20 AWG | Doorbells, alarm systems | Up to 60 ft |
| 18 AWG | CCTV cameras, landscape lighting, LED strips | Up to 100 ft |
| 16 AWG | Long runs for higher power devices | Up to 150 ft |
| 14 AWG | High-power LED or multiple light runs | Up to 200 ft |
| 12 AWG | Long-distance or heavy-load installations | 200+ ft |
Note: The exact distance depends on voltage, current draw, and allowable voltage drop (usually under 5%).
How to Choose the Right Wire Size
When selecting wire size for a low voltage system, consider these factors:
- Voltage and Current (Amperage)
- The more current your device draws, the thicker the wire should be.
- Distance of the Run
- Longer wire runs increase resistance, causing voltage drop. Use thicker wire for longer distances.
- Type of System
- Cameras, LEDs, and audio systems each have different power requirements.
- Environment
- For outdoor or buried wiring, choose cables rated for direct burial or UV resistance.
- Material
- Copper wire offers better conductivity than aluminum. Always choose pure copper over copper-clad aluminum (CCA) for reliability.
Example: Choosing the Right Wire for CCTV
Let’s say you’re installing 12V security cameras that each draw about 500mA (0.5A) and you’re running cable 100 feet from the power source.
Using an 18 AWG copper wire is ideal because it can handle the current while keeping voltage drop minimal. If the run exceeds 150 feet, consider 16 AWG for consistent power.
This same principle applies to lighting or doorbell systems — always balance distance, amperage, and voltage when selecting the right wire.
Low Voltage Wiring Safety Tips
Even though low voltage wiring carries less risk than standard electrical systems, safety still matters. Follow these tips:
- Use UL-listed cables that meet safety and fire standards
- Avoid mixing high-voltage and low-voltage wires in the same conduit
- Label all connections clearly for maintenance and troubleshooting
- Test voltage at endpoints to confirm performance
- Hire a licensed low voltage contractor for complex installations
Professional Low Voltage Installation in California
If you’re planning a large low voltage project — like CCTV installation, network cabling, or outdoor lighting — working with certified installers ensures everything is wired safely and efficiently.
Professional technicians can calculate voltage drop, choose proper cable types, and install clean, code-compliant wiring that lasts for years.
Whether it’s a residential property in Sacramento or a commercial facility in Los Angeles, the right team can design a structured low voltage system that meets your performance goals and local building codes. Choosing the right wire size also depends on your protection system. Learn more about the three basic types of low voltage circuit breakers used to prevent overloads and ensure electrical safety.
Key Takeaways
- Most low voltage systems use 22–12 AWG wire depending on current and distance.
- Thicker wire (lower AWG number) reduces voltage drop over long distances.
- Always use pure copper cables for better conductivity.
- Consider environmental factors and compliance with local codes.
- When in doubt, consult a professional low voltage installer.