myenergi zappi [PEN Fault]

PEN Fault is code 29, and myenergi describe it as the internal protection against loss of the PEN conductor on the electricity supply having tripped. The action they publish is worth reading carefully because of a clause most owners skip: unplug the EV, make sure the fault has been removed, then press and hold the button to reset. Make sure the fault has been removed is doing all the work in that sentence. It is myenergi saying that the condition is outside the charger, that resetting does not address it, and that if it is still present the unit will simply trip again. What has happened is that the charger has detected a voltage condition consistent with the loss of the combined protective earth and neutral conductor on the incoming supply.

On the common UK domestic arrangement, that conductor doubles as the earth for the whole installation, and if it fails, anything earthed in the property can rise to a dangerous voltage — including a car on the drive with a cable plugged into it. That is why chargepoints are required to protect against it. myenergi list built-in PEN protection as meeting BS 7671:2018 Amendment 1:2020, and their installation manual explains the choice the regulation offers — an extra earth electrode or a device that detects the fault and disconnects — and that because the zappi has the detection built in, no earth electrode is needed with it. They also describe what happens when it operates: the zappi becomes completely isolated from the input supply, so all conductors present at the output socket or cable, including protective earth and control signals, will be safe, removing any risk of potential electric shock. The installation manual’s version of the reset is more specific than the user manual’s: check the continuity of the earth cable, then press the menu button for three seconds.

There is a documentation discrepancy worth knowing about, because it affects what you will find when you look this up. The June 2022 manuals print code 29 against two different messages in the same table — RCD Tripped, described as the internal earth-leakage protection having tripped, and PEN Fault — and the December 2022 and July 2023 revisions carry only PEN Fault at 29, with RCD Tripped gone from the table altogether, although the installation manual still says the display shows RCD Tripped! when the RCD operates. Both describe a protection device operating and both require the fault to be cleared before resetting, so the practical answer is the same, but if your manual and your display disagree, that is why.