Yes, it is generally safe to leave a charger plugged into the socket, even if no device is connected. Modern chargers are designed to operate efficiently and safely, even when they are turned on without a device connected.

However, if you are not using the charger or if you are going away for an extended period, it might be a good idea to unplug the charger. This saves energy and reduces the risk of any electrical issues, such as short circuits or overheating.

It is also important to note that some chargers may continue to consume a small amount of energy, even when no device is connected. This is often referred to as standby power consumption. If you are concerned about energy savings, you might choose to unplug the charger when it is not in use.