The answer to your question is a resounding “yes”. Anything designed to run on AC mains, in order to pass compliance testing, must be capable of operating on a fairly wide range of voltages without sustaining damage.
What is this range? That’s not quite so simple to answer. The mains distribution system carries power over great distances, forks at various points to supply different areas, and traverses several transformers where voltage changes occur. Losses occur at many points in this complex circuit and are proportional to load, so the more heavily loaded the entire system is, the lower the voltage consumers will receive.
The electricity supplier is able to ramp up capacity during peak times, and reduce during low demand times, and in this way can somewhat compensate for the increased losses when demand is at its highest. But, if during a peak period you are in a distribution area with low overall demand, you will receive a higher voltage than an area with high demand as the distribution transformer for your area will be under less load and producing lower losses.
At any given time, with a 240V specification, acceptable variation is +/-10% which equates to 216V to 264V, so an appliance must operate correctly on at least this voltage range. Further, wiring rules also allow for a voltage drop of 5% in any given installation, so the low end can be as low as 205V. You may notice though that if the 240V AC mains is close to the high end of its range, it is beyond the 10% requirement of a 230V appliance (253V). This is where it gets a little more complex.
Very few countries still officially rate their AC mains as 240V, but DO still call it 240V and rate their appliances as such. Australia committed to a 20 year plan in 1983 to convert to a nominal specification of 230V to align with European standards, in an effort to simplify the global manufacture of appliances. The unusual part of this is that our supply voltage did not change! What did change was the tolerance specification, which is now 230V +10/-6%. Effectively, this moves the upper limit down to 253V but leaves the lower limit practically unchanged at 216.2V. The 20 years was needed to ensure that the distribution system could be upgraded where necessary to assure this tighter regulation standard could be achieved. The end result is that our supply voltage will always remain in range for both 230V and 240V rated appliances.
Does it work in practice? My personal experience says no, and a recent review of the electricity grid has found that consumer installations of solar generation systems may be to blame. It’s currently sunny at my location and the voltage is 251.1V as measured by my energy distributor supplied smart meter. This is perilously close to the limit. I have a solar installation that, due to standards in Australia, MUST disconnect if the voltage exceeds 255V, and will only reconnect once it drops below 253V for 1 minute. This condition has triggered several times in the last year, and can often last for an hour or more.
It’s possible that there are several older solar installations directly affecting my distribution area that are either incorrectly configured, or not subject to the voltage increase protection requirement simply due to their age. Anecdotally, these may remain connected during the over-voltage condition preventing it from resolving immediately. However, a solution has been proposed to the standards. The solution is to allow grid operators to signal solar generation systems to reduce their output as needed. As the installed base of consumer generation systems increases, implementation of this system will become mandatory in order to ensure future stability of the power grid, and ensure that our 230V rated appliances are not subjected to over-voltage conditions.