There should be "DVMs for ordinary folks" designed that use analog meters (no batteries required), good to 600VAC, wired with a simple AC wall plug vice test forcing folks to use common test leads; plug in, and read, ...no mess, no fuss, no danger!
There is a plug in analog AC voltage meter if you live in the states that measures 95 to 135 Volts AC.
Most voltage in the US is 105 to 125 Volts AC.
My dad has one for his RV, he got it from
Camping World for around 10 dollars I think.
If you live outside of the states there are
plug in digital AC voltage meters that measure 80 to 300 Volts AC
But DMM can be cheap and easy to use, if your worried about damaging their wiring don't be, you will damage the meter or yourself long before you damage their wiring. I have fried more than one meter and have come in contact with electricity badly before, electricity can be dangerous, less than 1 amp can kill you and 100 volts is more than enough to push it through your body, but as long as you keep away from the metal tips of the meter probes and don't disassemble anything it should be fine.
For around $20 you can get a
plug in voltage meter and a
plug in outlet tester, that should tell you almost everything you need to know about their wiring.
or you could get a cheap tester kit at Wally World that has a DMM, a GFCI outlet tester, a pen voltage detector and a carrying case.
You can also get a "
Kill A Watt" monitor like the "Mains Power Meter" from Jaycar mentioned earlier, you can find the "Kill A Watt" monitor on
Newegg.
But you shouldn't be worried about using a DMM, its easy.
