Ohme [Overvoltage]

This is the clearest statement any manufacturer in this category makes about a fault that is not in their product, and it is worth reading in Ohme's own words: if the voltage level is higher than 253 volts or lower than 207 volts, Ohme will temporarily pause charging, and resume charging once the voltage levels are at a suitable level again. The charger will also show a red flashing error light when these voltage issues are detected, and they are recorded as overvoltage or undervoltage errors for your charger. So the unit is measuring the electricity supply arriving at your house, finding it outside the permitted window, and stopping.

Nothing in the charger has failed. There is a neat connection here that Ohme make elsewhere and that explains a lot. Their ePod manual describes the built-in PEN fault detection required by the Wiring Regulations, and gives its thresholds as exactly the same numbers — disconnecting the vehicle if the voltage is greater than 253 volts or less than 207. So on an Ohme, an overvoltage error and a PEN fault disconnect are the same measurement. The remedy is the useful part, and it is not one most owners would arrive at.

Ohme publish that your distribution network operator can test the voltage levels at your home and help adjust them to the correct level. They add practical detail: for accurate testing the operator needs to monitor over the course of a few days, because a single reading may not pick up the issue, as voltage fluctuates through the day and night. And they say something reassuring while that happens — during the monitoring period they recommend continuing to use the charger as usual. Once the level is confirmed, the operator resolves it at your local substation. Why voltage rises in the first place is worth knowing. A street where several houses export solar generation sees local voltage climb on bright afternoons, because exporting means pushing slightly above the grid. That produces high-voltage events at predictable times of day, which is precisely why one reading misses them.

1. 1

   Open the app and look at the live mains voltage. Ohme show it as a display field on the Home and Go, which lets you see the problem rather than infer it.

2. 2

   Note when it happens. Bright afternoons point at solar export raising the local voltage; evening peaks point the other way.

3. 3

   Check the error record in the app. Ohme log these as overvoltage or undervoltage errors, which is exactly the evidence a network operator will want.

4. 4

   Contact your distribution network operator rather than Ohme. That is Ohme’s own published route, and the operator is the party who can adjust it. UK Power Networks, for their part, ask charger owners to have the installer or an electrician rule out the equipment first, then report online; they describe an engineer visit and, if needed, a two-week voltage recorder.

5. 5

   Ask them to monitor over several days. Ohme make this point specifically — a single reading may not pick up the issue because voltage fluctuates through the day and night.

6. 6

   Keep using the charger while they monitor. Ohme recommend continuing as usual during the monitoring period, and the interruptions are the protection working.