Validating untrustworthy electrical socket plugs on the go

[pex]

Sometimes you need some juice on the go for a portable appliance whose battery needs charged or for which you need power to operate.  Sockets and the power they provide are necessarily ubiquitous.  I have even seen small polls with sockets on sidewalks down the street of a big city.

I want to be able to verify that a power source is 1) operating and 2) is unlikely to damage my equipment.  It would be nice to have a singular, compact device that performs all the testing that we conclude is necessary, but for now I just want to identify the tools anyone could acquire and use to make a reasonable guess as the the quality of a line.

I do not have an electronics background so this will just be applied tool use for the layperson.  Assume United States electrical grid and building code specifications.

I assume I will need to at least verify that the line is providing AC, that the voltage is 110 (115? 120? 125?) +/- 15 (?) V.  Do I need to check for amps?  I assume I will also need to measure cycles which ought to be 60hz +/- 10.  Do I need to be concerned about impedence or resistence or any other such thing?

So, I know I can find a pen-type contactless voltmeter at any regular store.  Can I use my multimeter to verify other values (except cycles, maybe?)

What is it I really need to do to get a preliminary integrity check?

[ahmad]

The question is how you will go about testing all this without having the men in black suits show up, filthy terr'rist!

[Rajagra]

The best you can reasonably do is hook up a voltmeter to check the voltage is right. If it has a min/max function you can leave it connected for a while to see if it varies at all. Unless the power is coming from a private generator you can assume the frequency of the AC is correct, not that it matters much for 99% of purposes.

Beyond that all you can do is plug something in and see if it works. A lamp with incandescent bulb would be useful, as you could not only see if it works, but also watch to see if the brightness varies. Steady light = steady supply. And the cost of any damage is limited to the bulb, unless the source is seriously the wrong type. In which case it is your life you are gambling. Three-phase supplies are best avoided if you don't know what you are doing, they don't follow normal earthing rules.

[wellington1869]

The question is how you will go about testing all this without having the men in black suits show up, filthy terr'rist!

yea, everyone knows terrorists dont exist!

The best you can reasonably do is hook up a voltmeter to check the voltage is right.

i read that as "hook up a volunteer"

I suggest the hot-dog-and-two-forks test.

[ricercar]

This is the kind of thing I keep in my onsite music recording gig bag. It is durable, inexpensive, tells you what you need to know to prevent grounding problems, and can be easily replaced when it runs away from home.