C-Bus Random
Switching
Ghost Fault. Fix It Fast.
Lights turning on at 3am with no command sent. Zones activating randomly during the day. Circuits triggering without anyone touching a switch. This is a C-Bus ghost message fault — corrupted data packets on the network being interpreted as commands by relay units. The root cause is almost always a failing power supply. It won't stop on its own.
Are You Seeing
These Signs?
These are the specific symptoms that point to this fault. If you're seeing two or more, call now — don't wait for total failure.
- Lights or circuits turning on at night without any switch or app command
- Random zones activating during the day — no pattern or schedule matches
- Multiple different groups triggering unexpectedly across the property
- Lights turning on at similar times each night (repeating ghost command pattern)
- C-Bus Toolkit logs show unexpected group address transmissions
- The fault started intermittently and is becoming more frequent
- Other symptoms present including flashing switch LEDs or units dropping off network
What's
Actually Wrong
These are the physical causes behind this fault — in order of likelihood. We trace the root cause before any parts are replaced.
Degrading C-Bus Power Supply
The primary cause of ghost messages. As PSU capacitors age, the DC bus voltage becomes unstable — ripple increases, and the PSU outputs corrupted voltage waveforms. C-Bus units on the network misinterpret these as valid protocol packets and execute them as commands. Ghost messages almost always precede complete PSU failure.
Corrupted Unit Network Address
A C-Bus unit with a corrupted or conflicting network address can transmit malformed packets that trigger other units. This can occur after a power event, a failed firmware update, or physical damage to the unit's EEPROM memory. The corrupted unit continuously broadcasts noise.
Bus Impedance / Noise from External Source
Excessive electrical noise on the C-Bus cable — from nearby switchmode power supplies, VFDs, LED drivers, or building plant — can create signal distortion that gets misinterpreted as C-Bus protocol messages. More common in commercial premises or where LED retrofits have introduced incompatible drivers.
Failing Relay Unit Generating Feedback
A relay output unit with a failing output stage or damaged PCB can generate back-EMF or voltage spikes on the network that look like ghost packets to adjacent units.
What to Do
Right Now
Before we arrive — these steps protect your system from further damage.
Record zone names and approximate times of activation. If there's a pattern (same time each night, same groups each time), this is diagnostic data that helps identify the source.
Log into C-Bus Toolkit or your app and check scheduled events for the affected group addresses. Sometimes what appears to be ghost switching is actually a rogue schedule entry. If schedules are clear, it's a hardware fault.
Isolating loads is a temporary measure but doesn't fix the root cause. The PSU (or corrupted unit) continues generating noise that can affect other parts of the system.
The sooner ghost switching is diagnosed, the lower the risk of the fault cascading into a full PSU failure. We connect with C-Bus Toolkit, monitor live bus traffic, and identify the source precisely.
From Call to
Fixed — Fast
No runaround. No subcontractors. No second appointments.
Call or SMS
Describe your fault. We triage immediately and confirm attendance for the same day or next available slot. You speak directly with George — no call centres.
⏱ 5 minutesOn-Site Attendance
We attend with C-Bus Toolkit, test equipment, and common spare parts. The person on the phone is the person who shows up.
⏱ Same day where possibleFault Diagnosis
We connect to the network, read the system file, and trace the fault methodically. You get a clear explanation before any work proceeds.
⏱ Usually 30–60 minRepair & Restore
Most faults are fixed in a single visit. We carry common C-Bus spares and source directly from Schneider where needed. System documented before we leave.
⏱ Most faults: 1 visitStraightforward
Pricing
Fixed labour rates, no hidden fees. All work quoted before proceeding. Parts additional at cost.
- Monday–Friday, 7am–5pm
- Fault diagnosis & repair
- C-Bus Toolkit connection included
- Written fault report
- Parts additional at cost
- Priority same-day scheduling
- Fault diagnosis & repair
- C-Bus Toolkit connection included
- Written fault report
- Parts additional at cost
- Strata & commercial welcome
- Evenings, weekends & public holidays
- Fault diagnosis & repair
- C-Bus Toolkit connection included
- Written fault report
- Parts additional at cost
All rates are for labour only. Replacement parts and consumables are additional and quoted before supply. No GST applicable — ABN 61 136 364 150.
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Emergency Guides
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Quick
Answers
Why do the lights always come on at the same time — like 3am every night?
This is the C-Bus network receiving a repeating ghost command at that time. The most likely cause is a corrupted schedule in the network controller that has a group-on command logged at 3am, or a PSU voltage cycle that produces a recognisable noise pattern at the same point in its degradation cycle. We diagnose via C-Bus Toolkit live bus monitoring.
Can ghost switching damage other parts of my C-Bus system?
Yes. A failing PSU generating ghost messages is also feeding unstable voltage to all units on the network. Over time, this can corrupt unit address data and stress relay output circuits. Ghost switching is the warning — full PSU failure and cascading unit damage is the outcome if left unresolved.
My C-Bus was reprogrammed but ghost switching is still happening — is it still a programming issue?
If reprogramming didn't fix it, it's almost certainly a hardware fault — either a failing PSU or a corrupted unit. Programming changes don't resolve hardware-generated noise on the bus.
The ghost switching only happens at night — does that tell us anything?
Night-time ghost switching is often related to ambient temperature drops. PSU capacitors with borderline performance can fail to maintain clean bus voltage when ambient temperature drops — which typically occurs at night. This temperature sensitivity is a strong indicator of impending PSU failure.
Can a new LED retrofit have caused ghost switching to start?
Yes. Certain LED drivers — particularly uncertified or poorly filtered models — introduce switching noise onto circuits shared with C-Bus cable runs. If ghost switching started shortly after an LED retrofit, we'll check driver compatibility and cable routing on-site.
Send Us a
Message
Fill out the form and we'll get back to you fast — usually within the hour during business hours. For urgent faults, call 0422 469 739 directly.
C-Bus Down?
Don't Wait.
Every hour a failed C-Bus system runs in a fault state, more damage cascades through the network. Call now and we'll get it sorted — same day where possible.