The RS485 bus connects all Hybird breakers to the Edge Controller. Correct wiring is essential for reliable communication. This article covers the wiring specifications and best practices.
Cable specifications
Each Hybird breaker package includes pre-cut RS485 wire rated to 110°C and 600V. This wire is sized to connect breakers to each other in the daisy chain. Use the included wire for all breaker-to-breaker connections.
Topology
The RS485 bus uses a daisy-chain topology:
Connect the controller's RS485 terminal to the first breaker.
Connect the first breaker to the second breaker using the included wire.
Continue chaining from breaker to breaker.
The last breaker in the chain is the bus endpoint.
Do not use star or T-branch topologies. These cause signal reflections and communication errors. Every connection should be point-to-point in a single chain.
Communication parameters
Parameter | Value |
Protocol | Modbus RTU |
Bus speed | 500 Kbps |
Maximum devices per controller | 80 (practical limit — 247 is the theoretical Modbus limit) |
Bus termination
Termination resistors (120 Ohm at each end of the bus) should be used for basic Modbus topologies. For runs outside the panel longer than approximately 30 metres, using termination resistors and repeaters is recommended. Ultimately the installer chooses the approach that suits the installation.
Cable length inside the panel is not a practical concern — Hybird's in-panel daisy chains are short and well within RS485 limits.
Wiring tips
Keep connections tight. Loose terminals are the most common cause of intermittent RS485 communication failures. The Modbus plug is hand-tightened to a firm fit — no torque wrench required.
Maintain polarity. RS485 uses two signal wires (A and B). Maintain consistent polarity throughout the chain — if the wires are crossed at any point, communication will fail for all downstream breakers.
Route away from high-power cables. Keep the RS485 wiring separated from high-current power cables where possible to reduce electromagnetic interference.
Use the included wire. The wire included with each breaker package is rated for the thermal and voltage conditions inside an electrical panel (110°C, 600V).
Troubleshooting
If breakers are not appearing in the Hybird OS Platform or data is intermittent:
Check all terminal connections for tightness.
Verify polarity is consistent throughout the chain.
Check for any damaged or pinched wire.
Disconnect the last few breakers in the chain and re-scan — if communication restores, the issue is in the disconnected segment.
For long runs outside the panel, verify termination resistors are fitted at each end of the bus.
For persistent issues, contact Hybird support at [email protected] or call +45 3020 4900.
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