What Is the Maximum Distance for Low Voltage Wire? Complete Guide for Home and Commercial Systems
If you’ve ever wondered, “What is the maximum distance for low voltage wire?”, you’re not alone. Whether you’re installing landscape lighting, security cameras, or an access control system, understanding how far low voltage power can travel safely is crucial for performance and safety.
Low voltage wiring is used in many modern applications — from CCTV and alarms to smart home devices. But go too far without proper planning, and your system can lose power, signal strength, or even fail completely.
This guide explains how to calculate the right distance for your low voltage wiring, what factors affect it, and how to ensure your system runs efficiently. Our experienced low voltage wiring specialists in San Jose ensure that every installation meets proper distance and performance standards for safety and efficiency.
What Is Low Voltage Wiring?
Low voltage wiring refers to electrical systems operating at 50 volts (V) or less, commonly 12V, 24V, or 48V. It’s used for systems that don’t require standard household current, including:
- Security cameras and alarm systems
- Landscape and pathway lighting
- Doorbells and intercoms
- Access control systems
- Thermostats and building automation
- Network and audio-visual cabling
Because these systems use less power, they’re safer and easier to install — but they’re also more sensitive to voltage drop over long distances.
Understanding Voltage Drop
As electricity travels through a wire, it loses a small amount of voltage due to resistance. This is known as voltage drop.
If the drop is too high, your devices may not receive enough power to operate correctly. For example:
- LED lights may appear dimmer
- Security cameras may lose signal
- Door locks or sensors may malfunction
To avoid these issues, you need to understand how wire size (gauge), voltage, and current draw affect maximum distance.
What Is the Maximum Distance for Low Voltage Wire?
The maximum distance for low voltage wire depends on three main factors:
- Wire gauge (AWG) – Thicker wires carry power farther with less voltage drop.
- Voltage level – Higher voltage can travel longer distances.
- Current draw (amperage) – Devices that use more current reduce the allowable distance.
Here’s a general guideline for 12V systems, which are common in lighting and low voltage power:
| Wire Gauge | Max Distance for 5% Voltage Drop | Example Applications |
|---|---|---|
| 18 AWG | ~20-25 feet | Doorbells, sensors |
| 16 AWG | ~30-40 feet | LED strips, landscape lights |
| 14 AWG | ~50-60 feet | CCTV power runs |
| 12 AWG | ~100 feet | Outdoor lighting, longer CCTV runs |
| 10 AWG | ~150+ feet | Long landscape or gate wiring |
For 24V systems, you can typically double these distances because higher voltage reduces the percentage of voltage drop.
Pro Tip: Always try to keep voltage drop under 5% to maintain reliable operation.
How to Calculate Voltage Drop
If you want a more precise estimate, use the voltage drop formula:
Voltage Drop = (Current × Length × 2 × Resistance per ft) / 1000
You can find resistance values for each wire gauge in electrical tables or use online voltage drop calculators.
For most low voltage applications, it’s easier to:
- Choose a thicker wire (lower AWG number)
- Increase voltage (e.g., 24V instead of 12V)
- Shorten wire runs
- Split power across multiple circuits
Common Low Voltage Systems and Recommended Wire Distances
1. Security Cameras (CCTV)
CCTV systems often run on 12V DC. To avoid signal or power loss, keep runs under:
- 100 ft using 14 AWG
- 150 ft using 12 AWG
Or use PoE (Power over Ethernet) with Cat6 cables for longer distances (up to 328 ft per TIA standards).
2. Landscape Lighting
12V landscape lighting is sensitive to voltage drop. Use:
- 12 AWG for up to 100 ft
- 10 AWG for longer runs
You can also install multiple transformers closer to lighting zones for balance.
3. Access Control & Door Systems
Most access systems operate on 24V DC. With 18 AWG wire, you can safely run up to 100-150 ft depending on current load.
Choosing the Right Low Voltage Wire
When selecting low voltage wire, always consider:
- Voltage and current rating of your devices
- Distance from power supply to device
- Environmental conditions (indoor, outdoor, direct burial)
- Regulatory codes (NEC, local building codes in California or your state)
For outdoor and underground use, look for CL2-rated or direct-burial low voltage cables to meet safety requirements.
How to Extend Low Voltage Runs Safely
If you need to exceed the recommended maximum distance, here are safe ways to do it:
- Use heavier gauge wire (e.g., upgrade from 16 AWG to 12 AWG)
- Increase system voltage from 12V to 24V
- Install additional transformers or power supplies closer to loads
- Use PoE extenders for network-based devices
- Keep all connections tight and corrosion-free
Final Thoughts
The maximum distance for low voltage wire depends on voltage, current, and wire gauge — but proper planning ensures your system performs reliably. If you’re curious about how far current can travel before voltage drop occurs, you can read more about it in our article on how low voltage travels long distances.
For most residential and commercial projects, keeping runs under 100 feet (with the right gauge wire) provides the best balance of efficiency and performance.
If you’re unsure about your setup, it’s always best to consult a licensed low voltage contractor who can calculate voltage drop and recommend the proper wire size for your installation.
With the right design and materials, your low voltage systems will operate safely and efficiently for years.