The consensus seems to be that these cheapos, while useful for extremely low-current, low-voltage work, are not suitable for working with mains.
I do not think anyone here would suggest that the meters discussed in this particular thread can be considered "safe" for household use, let alone industrial applications. If safety is your concern, that is what you are paying for, not the meter.
I'm interested in this model because of what it can do at the lowest ranges, but I wouldn't trust my life to the diaphamous input protection on the device when working with higher voltages, and I don't recommend you do either.