Data Logger for Voltage and Current Surge?

Well, in a way your UPS is doing this for you. Most come with some sort of 'monitor' program that you can run to monitor/record such things.
It's quite possible you just have a faulty outlet. Or it could be a loose/bad connection in the service panel. Or......
Start with the UPS you have and see if there is any documentation about a 'monitor' mode or program you can install from the CD that may have come with it.
daestrom

This is an international group - you need to state your country for specific equipment recommendations.
For suspected sustained voltage excursions that last for several seconds/minutes- a recording voltmeter linked to a pc will give you the information you require, such as:
You can log the information on the computer and then present it in spreadsheet/graphical form.
This probably won't detect spikes of short duration - unless they are very frequent. But mains filters should elminate these.

Yes, but remember the UPS is taking one brief measurement every N minutes. Unless the surge is sustained, you usually won't catch it in a UPS log. You catch the event indirectly by a log message that says some unquantified voltage surge caused the unit to go on backup power, but the detailed voltage log simply skips over that time. Even if I fine tune the log to take a measurement once each minute I may miss details on most of the events.
I was hoping to find a device that takes a measurement and records every N minutes by default, but if there is a surge, then it immediately records the voltage and current measurement at that instant, so you don't get data overload from too many measurements, but you also don't lose out on measurement of abnormal events.

I don't think there is any such animal as a 'cheap' volt/current logger. Try googling for things like electrosoft/ ranger1000 or Lem but they are quite expensive if you only want them for one job. Can't you ask your supplier to do it for you? It's usually a free service.
Jb

Do you want data, or do you want to identify a problem? For example, if voltage variations are excessive, then an incandescent lamp changes intensity. Ball park quantifying of intensity variation provides useful information. For example, a computer must work just fine even when voltage drops so low that the incandescent lamp is at 40% intensity. Furthermore, if intensity variations are on some circuits and not on others, then you have identified symptoms of potentially dangerous building wiring problems.
Another alternative is a 3.5 digit multimeter with a high and low function. IOW they display the current voltage AND store the highest and lowest values. This will also quantify the problem - numbers being so important to find a problem and to confirm the problem has been solved. (Too many only want to cure symptoms when no using quantitative data.)
Will wrote: