Wireless Control · Serious Power
GC-40 Z-Wave High Current Relay Controller
Switch high-power loads with any Z-Wave hub. The GC-40 pairs an industrial 40 amp contactor with a Remotec Z-Wave module, so your smart-home controller handles only the low-voltage control circuit while the heavy contactor does the switching. The result is reliable wireless control of pumps, motors, heaters and other high-current equipment — with full electrical isolation between your electronics and the power side.
Most Z-Wave switches top out around ½ HP and were never built to drive real loads. The GC-40 is engineered around a true power contactor and shipped pre-wired in a weatherproof enclosure, ready to install and control from anywhere.
Key Features
- Z-Wave wireless controlPairs with any Z-Wave hub — SmartThings, Hubitat, Home Assistant and more — for on/off control and automation from anywhere.
- 40A industrial contactorA JQX-38F power contactor switches high-current loads that would overwhelm a standard smart relay.
- True electrical isolationThe Z-Wave control circuit is physically separated from the power circuit, protecting your hub and electronics.
- Rugged, weatherproof enclosureNEMA 4X (IP66) polycarbonate housing rated for indoor and outdoor installation.
- Tool-free WAGO connectionsLever connectors make control wiring fast, secure and maintenance-free — no soldering.
- Pre-wired and ready to installThe control side arrives factory-wired and tested — just add line and load with a licensed electrician.
How It Works
- Your Z-Wave hub sends an ON/OFF command to the Remotec module.
- The module energizes the contactor's 120VAC control coil.
- The industrial contactor switches the high-power load on or off.
- Electrical isolation keeps the control circuit fully separate and safe.
Specifications
| Relay / Contactor | JQX-38F — 40A, 120VAC |
|---|---|
| Z-Wave Module | Remotec ZFM-80US |
| Control Voltage | 120VAC, 60Hz |
| Contact Rating | 40A resistive @ 120VAC (refer to relay datasheet for full load & duty ratings) |
| Enclosure | NEMA 4X (IP66) polycarbonate |
| Control Wiring | 16/18 AWG (factory installed) |
| Load Wiring | Not included — field installed by a licensed electrician |
| Dimensions | 6.7″ H × 5.7″ W × 3.5″ D |
Why the GC-40 Is Better
| Feature | Standard Z-Wave Relay | GC-40 Controller |
|---|---|---|
| Switches high-power loads | Limited (<½ HP) | Up to 40A contact rating |
| Electrical isolation | No | Yes |
| Industrial contactor | No | Yes |
| Rugged enclosure | No | Yes (NEMA 4X) |
| Installation | DIY / exposed | Pre-wired / enclosed |
| Ready for high current | No | Yes |
Built For Real-World Applications
Installation & Safety
Professional installation required. The GC-40 is a component intended for installation by a qualified, licensed electrician.
High-voltage wiring (line and load) is not included. Use appropriate conductor size and overcurrent protection for your application. The factory control wiring (16/18 AWG) is for the control circuit only and is not rated for high-current loads.
Final circuit rating is determined by the installed conductor size, terminal ratings, connected load, and applicable electrical codes.
Powered by Z-Wave
Smarter Than Wi-Fi for Controlling Real Devices
Z-Wave is a wireless technology built for one job: controlling the things in your home reliably. It runs on its own low-power network, so it stays fast and steady where Wi-Fi gets crowded and drops out.
How Z-Wave Works
Instead of every device shouting at a single Wi-Fi router, Z-Wave devices form a self-healing mesh network. Each mains-powered device also acts as a repeater, passing signals along until they reach your hub. Add more devices and the network gets stronger and wider, not weaker.
Z-Wave vs. Wi-Fi
| What matters | Typical Wi-Fi Device | Z-Wave |
|---|---|---|
| Wireless band | Crowded 2.4 GHz, shared with phones, laptops & neighbors | Dedicated sub-1 GHz band — far less interference |
| Network shape | Every device back to one router (single point of failure) | Self-healing mesh — devices relay for each other |
| Range & walls | Weakens through walls and floors | Lower frequency penetrates better; mesh extends it further |
| Impact on your internet | Uses router bandwidth & IP addresses; can slow browsing | Runs on its own network — your Wi-Fi stays free |
| Power use | High — battery devices drain quickly | Very low — battery sensors can last for years |
| Reliability | Often depends on the cloud & a strong signal | Local mesh control keeps working even in a busy RF environment |
| Works together | Brand apps that don't always talk to each other | Certified devices from any brand interoperate, with modern S2 security |
The bottom line: Wi-Fi is great for streaming and browsing — but for switching devices on and off dozens of times a day, you want a network built for control. Z-Wave delivers fast, reliable, low-power commands without ever clogging your internet. This controller pairs with any Z-Wave hub, so it drops right into the ecosystem you already have.
Z-Wave is purpose-built for control signals rather than high-bandwidth data like video, and North American Z-Wave operates around 908 MHz. Actual range and device limits vary by hub and installation.