This failure means the residual current device itself is faulty, rather than a real residual current being present. Check the device with its test button: pressing it simulates a fault, so the output should then be dead. If voltage is still present after pressing the test button, wire the device correctly and switch it back on. Do not confuse it with a real residual current shutdown, which is usually caused by faulty earth cabling, often shows up during rain, and is confirmed by an insulation resistance measurement. High leakage currents can upset the residual current calculation and cause unwanted shutdowns. If an external device trips often, set the inverter's rated residual current lower.
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affectsc1 verified · fact Residual current device
tbl=72.r6 h=3d221759bedasec=6.2 h=6c6a213ef52btbl=24.r1 h=473b0dc9debdverified by: review-workflowverified on: 2026-10-23
detected_byc2 verified · fact Inverter display check
The fault is shown as a status message on the inverter web interface.
tbl=72.r6 h=3d221759bedaverified by: review-workflowverified on: 2026-10-23
c3 verified · fact RCD test button check
Pressing the device's test button simulates a fault; afterwards check whether voltage is still present downstream.
sec=6.2 h=6c6a213ef52btbl=24.r1 h=473b0dc9debdverified by: review-workflowverified on: 2026-10-23
mitigated_byc4 verified · fact Wiring and terminal check
If voltage is still present at the output after the test button is pressed, rewire the residual-current device correctly and switch it back on.
tbl=24.r1 h=473b0dc9debdverified by: review-workflowverified on: 2026-10-23
c5 drafted · lead Inverter parameter adjustment
If an external residual-current device trips frequently, set the inverter's rated residual current lower so the inverter disconnects first.
sec=8.12 h=18f0a2f177b5review note: support check: partial - Lowering the inverter value when the device trips frequently is stated, but the passage doesn't call this a mitigation of device failure. It also describes the inverter disconnecting to prevent incorrect tripping, not 'first' as such.; review: partial - Setting the inverter value lower when the RCD trips frequently, so that the inverter disconnects and prevents incorrect tripping, is stated; but that is nuisance tripping, not a failure of the device, so calling it a mitigation of device failure…
caused_byc6 drafted · lead Leakage current
When leakage currents are high, the residual current cannot always be calculated accurately, and the calculation errors can cause unwanted inverter shutdowns.
sec=h11 h=63b3fad3802creview note: support check: partial - High leakage currents causing calculation errors and unwanted inverter shutdown are stated, but the passage says nothing about a residual current device failure.; review: partial - Unsupported is too harsh. The passage says high leakage currents keep the RCMU (the inverter's residual-current monitoring unit) from calculating residual current accurately, and that these errors can cause an undesired inverter shutdown. That is leakage current causing the residual-current…
distinguished_fromc7 drafted · lead Loss of electrical insulation — told apart by Insulation resistance testing
A genuine residual-current trip usually comes from faulty earth cabling or low insulation resistance, which an insulation test confirms. A fault in the device itself is reported as a separate module-fault status.
tbl=72.r4 h=e8cf06dd4b30tbl=42.r1 h=53a521edab18tbl=72.r6 h=3d221759bedareview note: support check: partial - The residual current shutdown, with faulty earth cabling and an insulation resistance measurement, and the separate AFI module fault are stated. The passages do not say that an insulation test tells the two apart.; review: partial - The passages separate the residual-current shutdown (faulty earth cabling or low insulation, check by measuring insulation resistance) from a distinct AFI module fault status, but never say the insulation test is how the two are told apart.
indicates c2indicates c3