240V vs. 250V
2. The Tolerance Question
Okay, let's get back to the core question: can you plug a 240V device into a 250V outlet? The slightly unsatisfying, but most honest, answer is: it depends. Generally, a 10V difference isn't likely to cause immediate catastrophic failure. Most modern electronics have some degree of tolerance built in, and the power supply inside the device will often attempt to regulate the voltage. But, and this is a big but, it's not a guaranteed free pass.
Many devices, particularly those with switch-mode power supplies (think laptops, phone chargers, and many modern appliances), are quite robust and can handle a wider range of input voltages than their label suggests. These power supplies actively regulate the voltage going to the internal components, so a small difference in input voltage often gets smoothed out. However, older or simpler devices, especially those with transformers or motors, might be more sensitive.
If the 240V device is a simple appliance, like a heating element or an old-fashioned lamp without any complex electronics, then it's probably more vulnerable. The extra voltage could cause it to overheat or burn out faster. On the other hand, a sophisticated laptop power adapter is much more likely to shrug off that extra 10 volts.
Before you plug anything in, take a close look at the device's label. Does it say something like "220-240V" or "100-240V?" If it indicates a range that includes voltages higher than 240V, you're probably in the clear. But if it strictly says "240V" with no wiggle room, proceed with caution.
