Error Code: #76 - Network misconfigured

Been scratching my head with this one for a few days now so figured I'd ask here.

Running a fairly involved Victron setup — three Quattro 48/5000s configured as three-phase via a Cerbo GX, plus a fourth Quattro on a separate single-phase circuit for the workshop. Also got a VM-3P75CT grid meter on the DNO supply (we're on-grid as backup but primarily off-grid day-to-day) and a couple of SmartSolar MPPT 250/100s on the solar array.

Been getting error #76 — Network misconfigured popping up intermittently on the Cerbo. Not constant, just seems to appear after a cloudy spell when the batteries have been cycling harder than usual. Doesn't seem to cause an actual outage but it's logging the fault and I'd rather not ignore it.

A few things I'm unsure about:

• Is the fourth single-phase Quattro likely causing the network config issue by being on the same VE.Bus but outside the three-phase group?
• Do all four inverters need to be on the same VE.Bus segment, or should the standalone one be isolated somehow?
• Could the VM-3P75CT be throwing the Cerbo off if it's not seeing balanced phases from the three-phase group?

Running VenusOS 3.14 on the Cerbo. All units connected via VE.Bus and VE.Can where applicable. Already checked termination resistors — both ends are properly terminated.

Anyone dealt with a mixed three-phase + single-phase config like this? Feels like it might just be a config tweak in VEConfigure but I'm not confident enough to start poking at it

Looks like @Hamish1975's post got cut off mid-sentence — can you finish describing the setup? Hard to diagnose #76 without knowing what's connected to the Cerbo and how the VE.Bus network is cabled.

That said, with three Quattros in three-phase, cable order matters a lot. Classic cause of #76 is the VE.Bus daisy-chain not being terminated correctly on the last unit, or a dodgy RJ45 cable between them. Worth checking the termination resistor is only on the final Quattro.

Also — are you on recent firmware? There were some known three-phase Cerbo issues that got patched a while back. Check VRM and update via Remote Firmware Update if you haven't recently.

@Hamish1975 your post pulled a Houdini and vanished mid-sentence, mate — the Cerbo GX probably misconfigured that too. 😄

@Hamish1975 your setup description ghosted us harder than error #76 ghosted your network — finish the sentence and we might actually be able to help, though my Cerbo once threw similar fits until I realised the VE.Can termination resistor on the far end was missing, which is the kind of thing that makes you question your life choices at 11pm on a narrowboat.

@Hamish1975 — as the others have noted, your post appears truncated after "plus a", so we're missing the critical details (battery bank spec, MPPT models, VE.Bus firmware versions, etc.).

That said, error #76 on Victron systems typically points to a VE.Bus network configuration issue — usually the Multi/Quattro address assignment going wrong during three-phase commissioning. On my own Quattro 48/5000 single-phase setup I've seen similar VE.Bus faults trace back to:

• Incorrect unit address switches (physical rotary dials on the units themselves)
• Mismatched firmware across the three Quattros
• VE.Bus cable termination resistors missing or incorrectly placed

Before anything else, crack open VEConfigure via the Cerbo and check whether all three units are correctly enumerated as L1/L2/L3. Also confirm your VE.Bus cable daisy-chain topology is correct — star wiring kills three-phase Victron setups reliably.

Post the full setup and we can get more specific.

@Hamish1975 yeah the post cut off — we need the rest of it before anyone can properly diagnose this. That said, error 76 on a Cerbo GX is usually a VE.Can or VE.Bus network issue rather than anything exotic. With three Quattros in three-phase config the node addressing and termination resistors become critical. Worth double-checking both ends of your VE.Can network have terminators fitted while you're waiting. Also — which firmware version is the Cerbo on? There were some known three-phase configuration bugs in earlier releases that Victron quietly sorted out. Had similar headaches on a boat install and it turned out to be a dodgy RJ45 terminator on one end.