Generac low voltage wiring refers to the wiring used to connect control signals between a Generac standby generator, automatic transfer switch (ATS), and sometimes accessories like load shed modules or remote monitors. While the generator itself handles high-voltage power, the low voltage control wiring is essential for automatic operation and communication.
generac low voltage wiring
In this guide, you’ll learn:
What low voltage wiring is used for in Generac systems
Recommended wire types & gauges
Typical wiring diagrams and signal types
Troubleshooting low voltage wiring issues
NEC codes and best practices
🔌 What Is Low Voltage Wiring on a Generac Generator?
In Generac systems, low voltage wiring typically connects:
The generator controller (e.g., Evolution 2.0)
The Automatic Transfer Switch (ATS)
Optional devices: remote monitoring, smart management modules, Wi-Fi/ethernet modules
These connections use 12V to 48V DC signals, classified under Class 2 or Class 3 NEC power-limited circuits, which are separate from the high-voltage AC output.
📦 Common Low Voltage Connections in Generac Systems
| Connection | Typical Wire | Voltage | Description |
|---|---|---|---|
| Generator to ATS (control wires) | 14 AWG THHN or 18/2 Thermostat | 12V–24V DC | Signals the ATS to switch loads |
| Generator controller to Wi-Fi/Ethernet | Cat5e or Cat6 | 5V–48V PoE | For internet communication (Mobile Link) |
| Load Shed Modules (Smart Mgmt Modules) | 18/4 or 18/2 shielded | 24V DC | Control individual circuits |
| Battery charger monitor | 2-wire low voltage | 12V DC | Maintains and monitors battery voltage |
| Remote monitor/display panel | 4-conductor cable | 12V–24V | Extends controller readout |
📐 Typical Generac Low Voltage Wiring Diagram
While specific diagrams vary by model, here’s a simplified view:
In air-cooled Generac systems (7kW–24kW), the N1 and N2 wires are the most common low voltage pair from the generator to ATS.
For liquid-cooled systems, control wiring may include more complex multi-pin harnesses or CAN communication.
📏 Wire Size & Type Recommendations
| Distance | Recommended Wire | Application |
|---|---|---|
| <50 ft | 18 AWG 2-conductor (Thermostat wire) | Generator ↔ ATS |
| 50–200 ft | 16–14 AWG THHN in conduit | Prevent voltage drop |
| Outdoor use | Direct-burial rated or conduit | Ensure weatherproofing |
Shielded wire is recommended in areas with high EMI (electromagnetic interference) such as near HVAC or other power-heavy equipment.
🧰 Installation Tips & Best Practices
Conduit is Required
Most local codes require low voltage wiring between the generator and ATS to be run in separate conduit from high voltage lines.
Keep Low and High Voltage Wires Separate
Never mix low voltage signal wires with AC lines; it can cause erratic operation or damage the controller.
Label Your Wires Clearly
Use tags or color codes, especially when running multiple pairs.
Secure Connections Firmly
Loose wiring can cause communication failure between the generator and ATS.
Follow NEC Article 725
All low voltage circuits should be rated and installed as Class 2 or Class 3 where applicable.
🛑 Common Wiring Mistakes to Avoid
Using too small of a wire gauge, leading to voltage drop
Running low voltage wires in same conduit as AC lines
Not using shielded cable in interference-prone areas
Forgetting to connect the battery charger wiring
Improper grounding or lack of surge protection
❓ Frequently Asked Questions
Q: What wire do I use for Generac N1 and N2 terminals?
A: Use 18/2 thermostat wire or THHN 14 AWG in conduit for longer runs.
Q: Can I use Cat5e for Generac communication?
A: Only for ethernet/Wi-Fi communication accessories. Not for generator-to-ATS control wiring.
Q: Is the 2-wire start truly low voltage?
A: Yes. It typically uses 12–24V DC signal and is classified as Class 2 low voltage.
Q: Can low voltage wire run outside?
A: Yes, but use UV-resistant, direct-burial rated, or place it in weatherproof conduit.
✅ Conclusion
Correctly installing and identifying Generac low voltage wiring ensures reliable standby power operation and long-term system performance. Whether you're wiring from a generator to an ATS or connecting a Smart Module, following best practices in wire type, sizing, and separation from AC lines is essential.
📞 Need Low Voltage Control Wire for Generac Installations?
TOT Wire & Cable supplies:
18/2, 18/4 thermostat wire
Shielded multi-conductor control cables
Direct burial low voltage cable
Cat5e/Cat6 for Wi-Fi and ethernet
UL/NEC Class 2/3 compliant cable
👉 Contact us today for bulk pricing and technical support!
