Undervoltage and overvoltage explained

Answer

An under or overvoltage event is when the voltage in your electricity supply drops below or exceeds the normal range. When this happens, your EV charger will trip and stop charging instantly to protect itself and your home.

If these events happen regularly, or rebooting your charger doesn’t work, it could be that there’s something wrong with your electricity supply. If so, you’ll need to get in touch with your local Distribution Network Operator (DNO). They’re the ones responsible for supplying electricity to your home and can help you get it sorted.

What should I do if my charger reports an undervoltage or overvoltage event?

  1. Check the Hive app
    • It’ll tell you if an undervoltage or overvoltage event (or another related issue) has happened.
  2. Reboot your charger
    • Head to your Charger Settings in the Hive app, scroll to the bottom and tap ‘Reboot charger’. Or you can do it manually on the charger itself – just switch it off, wait 10 seconds, and switch it back on again.
  3. Contact your Distribution Network Operator (DNO)
    • If rebooting doesn’t solve it, you’ll need to get in touch with your DNO. They’ll be able to check for any faults with your electricity supply and get them fixed. 

How do I contact my Distribution Network Operator? 

If you’re in England, Scotland or Wales, just call 105 free of charge from any mobile or landline. If you’re in Northern Ireland, call 03457 643643. You’ll automatically be put through to the DNO responsible for your area. Or you can find your local operator on the Energy Networks Association website.

Can a Surge Protection Device (SPD) help with overvoltage?

Yes, a Surge Protection Device (SPD) helps to protect your charger and other household electronics from sudden voltage spikes – such as those caused by lightning or grid switching. It works by safely diverting excess voltage to earth.

What is an Open PEN Detection Device (OPDD)? 

Most EV charger installations include an Open PEN Detection Device (OPDD). This safety device monitors your electricity supply for specific faults by detecting unusual voltage levels. If it spots a problem, it’ll automatically stop charging to protect your charger and vehicle.

It’s important to remember that an OPDD is different from an SPD. Each device has a separate purpose and provides protection against different types of electrical issues. 

What should I do if my OPDD unit indicates an undervoltage or overvoltage issue?

  1. Check the voltage
    • If you’re comfortable doing so, you can check your supply using a voltage meter. If not, you can ask your DNO to confirm whether your home voltage is outside the normal range.
  2. Contact your DNO
    • If the voltage is consistently below or above the standard range (typically 230V ±10% in the UK), your DNO may need to carry out further checks or adjust the supply.
  3. Speak to our support team
    • If you’ve confirmed your supply is within the normal range, there may be a problem with your charger or protective device. Get in touch with us as soon as possible, and our friendly support team will be happy to help.

 NOTE: The voltage supplied to your home is managed by the grid and your local Distribution Network Operator (DNO). Because of this, Hive cannot control or change the supply voltage.