Can You Charge an EV During a Thunderstorm? Wallbox, RCD and SPD Explained
Malaysia’s afternoon thunderstorms can arrive quickly, raising a very practical question for EV owners who charge at home: if the car is already connected to a Wallbox and thunder suddenly starts outside, should charging be stopped immediately?
The answer is not as simple as saying the charger is “waterproof”.
Ordinary rain and a thunderstorm present different risks. Compliant EV charging equipment is designed with weather and contact protection in mind, especially when installed outdoors. Thunderstorms add another layer of concern, including lightning, transient overvoltage, electrical surges and the risk of going outside to handle electrical equipment while lightning is nearby.
The simple answer: ordinary rain does not automatically make a properly installed outdoor EV charger unsafe. But “weather-resistant” should never be interpreted as “safe to ignore lightning”. Current vehicle safety guidance from several manufacturers warns against starting a charge when there is a risk of lightning.
Malaysia is a thunderstorm-prone country
Thunderstorms can occur throughout the year in Malaysia and are particularly common during the inter-monsoon periods around April to May and October to November.
METMalaysia notes that thunderstorms over land usually occur in the afternoon and early evening, and that every thunderstorm produces lightning.
Lightning does not always strike where the rain is heaviest. It can occur outside the main rain area, which means “it is not raining heavily here” is not a reliable way to judge lightning risk.
For an EV owner, the important question is therefore not only whether it is raining, but whether thunderstorm and lightning activity is already nearby.
Water resistance is not lightning protection
EV charging connectors, vehicle charge ports and Wallboxes are not automatically unusable simply because it is raining.
Malaysia’s Energy Commission 2025 EVCS guideline requires outdoor EV supply equipment enclosures to meet at least IP44, while indoor equipment must meet at least IP41. This reflects the fact that compliant charging equipment is expected to cope with the environment for which it is installed.
However, an IP rating does not mean the equipment can be submerged, and it is not a lightning-protection rating.
Modern EV charging systems also include multiple safety functions.
In Mode 3 charging, which is commonly used by home Wallboxes and public AC chargers, the charger communicates with the vehicle through the control pilot. The system confirms the connection state, monitors protective earthing and controls when electrical power is supplied or disconnected.
That is why a proper Wallbox is not simply a high-power socket feeding electricity directly into a car.
But these protections should not be interpreted as meaning that thunderstorms can simply be ignored.
Volvo’s Malaysia charging guidance advises against connecting the charging cable when there is a risk of a thunderstorm or lightning strike. Hyundai’s current owner guidance similarly warns against charging when there is a risk of lightning.
Toyota’s 2026 bZ owner’s manual goes further, advising that if lightning is noticed while DC charging, the vehicle and charging cable should not be touched.
The correct message is therefore: rain protection is one part of charging equipment design, while lightning is a separate risk. Owners should always follow the instructions for their own vehicle and charging equipment.
What do RCD, RCBO and SPD actually protect against?
Home Wallbox installations often mention RCD, RCCB, RCBO and SPD, but they do different jobs.
An RCD or RCCB is primarily intended to detect residual current or electrical leakage.
An RCBO combines residual-current protection and overcurrent protection in one device.
The Energy Commission’s 2025 EVCS guideline requires an EV charging point or charging socket to be supplied by a dedicated final circuit, with appropriate overcurrent and residual-current protection.
An SPD, meanwhile, is a Surge Protective Device. Its purpose is to limit transient overvoltage and reduce the effects of electrical surges on equipment.
Having an RCD at the Wallbox does not mean the whole house is protected from lightning-related surges.
Likewise, having an SPD does not remove the need for proper earthing, leakage protection, suitable cabling and correct installation.
Does every home with a Wallbox need an SPD?
Not necessarily.
The Energy Commission’s official FAQ states that whether an SPD is required depends on a risk assessment.
It would therefore be inaccurate to say that every Malaysian home with a Wallbox is automatically required by law to have an SPD.
A better approach is to have a qualified electrical professional assess the home’s distribution system, earthing, residual-current protection, surge protection and existing lightning-protection conditions when an EV charger is installed.
In areas that experience frequent thunderstorms, this is especially worth asking about rather than assuming the Wallbox alone covers every electrical risk.
EV charging safety starts at the distribution board
When people buy an EV, much of the attention goes to the Wallbox brand, whether it is 7kW or 11kW and how many hours a charge will take.
But a safe home charging system starts before the Wallbox.
The complete safety chain includes the home distribution board, cables, protection devices, earthing, isolation equipment, Wallbox, charging cable and the vehicle itself.
A premium Wallbox connected to unsuitable old wiring, an inappropriate shared circuit or a household electrical system that has never been properly assessed does not make the installation safe by itself.
What if the car is already charging when lightning starts?
This is probably the situation most owners worry about.
If a thunderstorm has not yet arrived but weather warnings show that severe weather is approaching, the sensible option is to end charging early while it is still safe to do so, following the normal procedure specified by the vehicle and Wallbox manufacturer.
But if lightning is already nearby, the priority changes.
Toyota’s guidance says that if lightning is noticed while charging, the vehicle and charging cable should not be touched. METMalaysia advises people to move inside a substantial building or a vehicle during thunderstorms.
In other words, do not run outside during an active thunderstorm just to pull out the charging plug.
Personal safety comes first.
Once the storm has moved away, charging can be stopped, checked or restarted according to the normal procedures for the vehicle and charger.
If the vehicle or Wallbox app allows charging to be stopped remotely, it may be used according to the manufacturer’s instructions. However, a remote “stop” command does not physically disconnect the charging cable from the electrical system.
What about public DC chargers during a thunderstorm?
Public DC charging stations are usually installed outdoors, but outdoor design does not mean drivers should ignore severe weather conditions.
During ordinary rain, a charger may be used if the station, connector and cable are undamaged, there is no flooding or fault warning, and the operator or vehicle manufacturer has not instructed otherwise.
Do not use charging equipment if the connector or contacts are visibly wet or damaged, or if operating the equipment requires standing in pooled water.
If there is active lightning, flooding, damaged equipment or a charger fault message, stop using the station and follow the vehicle manufacturer, charging operator and site safety instructions.
During an intense thunderstorm, getting into a safe building or remaining inside the vehicle is more important than repeatedly handling a charging connector outdoors.
The house tripped after lightning. Should charging restart immediately?
Do not assume everything is normal simply because power has returned.
If a lightning event was followed by a trip at the distribution board, activation of a protection device, a Wallbox error message, burning smell, scorch marks, unusual heat or water ingress, stop using the charger.
Do not repeatedly reset protection devices or open the Wallbox yourself to investigate.
If the issue was only a normal power interruption, first check the vehicle and Wallbox status for warnings before following the manufacturer’s restart procedure.
If anything appears abnormal, inspection by a qualified electrical professional or the charger service provider is the safer option.
The real question is bigger than “Is my Wallbox waterproof?”
Most EV owners do not need to become electrical engineers, but there are several useful questions to ask when a home charger is installed:
- Is the charger connected to a dedicated circuit?
- How are residual-current and overcurrent protection provided?
- Has the home earthing system been checked?
- Is an SPD already installed?
- Does the property require further surge or lightning-protection assessment?
These questions may have a greater impact on long-term charging safety than the number of app features built into the Wallbox.
EVs do more than change the fuel used by a car. They also connect a vehicle to the household electrical system for hours at a time.
That means charging safety cannot be judged by looking only at the car or only at the Wallbox. The distribution board, cable capacity, earthing, residual-current protection, surge protection, charger and vehicle all form part of one system.
For Malaysian owners living in a country where thunderstorms are common, “Can I charge in the rain?” is only the first question. The more useful question is whether the home charging installation has been properly designed and protected for electrical faults, surges and abnormal conditions.
And when an intense thunderstorm is already overhead, no charging session is worth putting personal safety at risk.
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