Low voltage shutdown?

Approximately how low could voltage go on a household current before a machine decides to turn itself off (go dead).

A client of mine is having random turn-off issues and I cannot find any hardware or software reason of this. Their entire house is on two 20A breakers and I'm wondering if this is the issue.

The machine is blown out and is fairly new so dust/heat isn't the problem. PSU rails look good along with multi-meter readings.

Thanks!

I dont know which input volatges you use, if the input voltage is 230V there should be only visible voltage drops.

Most PSU are designed for world wide use, so the voltage can drop to 110V with out any problems.