I have a Multiplus-II GX 48/5000/70, in France, configured with the right Grid value (eg VDE2019-XXXX).
Enedis in France give me some "nice" spikes around 254-256V several times a day.
Main problem with this kind of spike is that Enedis says "well" this "more or less" the tolerance values of the grid voltage (230V AC - 50Hz +/- 10%).
I know that 254-256V is more than +10%, but really I want to make the Multiplus less sensitive about those spikes.
Mostly because I have added UPS behind this Multiplus for all the computer room and they really complaining when Multiplus is taking care of the electricity... (APC and Eaton)...