Generac Low Voltage Wiring: Complete Guide for Standby Generators & Transfer Switches

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

📐 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

Shielded wire is recommended in areas with high EMI (electromagnetic interference) such as near HVAC or other power-heavy equipment.

🧰 Installation Tips & Best Practices

1. 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.

2. 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.

3. Label Your Wires Clearly

   • Use tags or color codes, especially when running multiple pairs.

4. Secure Connections Firmly

   • Loose wiring can cause communication failure between the generator and ATS.

5. 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!