How to know a power socket's voltage?

[Electroenthusiast]

Now, this might seem ridiculous for an engineer, who has a professional degree. But, i'm just asking this question. I don't know whether this question has been up anytime before, by me or anyone else. But, it is still stupid.

I was walking by a corridor in a mall, and felt like i can use the power sockets to power my laptop, when i need it. But, these power sockets are usually used for cleaning purposes (vacuum cleaners), which are motored at a certain voltage.

I then thought something like this. What would be the voltage that is fed by the power socket? It could be single phase 110V (or 220V) or single phase 440V (commercial voltage) too. How do i know what voltage it is by looking at the socket?

Again, this might seem silly because 440V is only used for three phase. Correct me if i am wrong.

Answers with Images would do good.

 

[For The Popcorn]

Sockets come in many different types. In North America, NEMA types are most common.

Most switching power supplies will handle 100v – 240v, but check the label for sure.

NEMA plugs

 

[Nigel Goodwin]

Move to a sensible country where they have sensible mains

In the UK (and most countries) there's only one mains voltage - here it's 240V (nominally 230V) - so the problem never arises, there's nothing wrong you could plug in. There are entirely different sockets for industrial use, which are three phase capable.

But in a mall, and certainly in customer areas, all sockets would be standard 240V 13A. Perhaps in plant areas there are three phase sockets?, but you couldn't plug a normal plug in anyway - and in fact they are so completely different I suspect no one would even think to try?.

 

[Electroenthusiast]

Yes, obviously a 3 phase socket cant be plugged to a laptop. But, is there any chance of having a different voltage at the supply, commonly?

To be direct, can there be a single phase 440V supply anywhere?

 

[Nigel Goodwin]

Yes, obviously a 3 phase socket cant be plugged to a laptop. But, is there any chance of having a different voltage at the supply, commonly?

To be direct, can there be a single phase 440V supply anywhere?

You might try mentioning what country you're in?.

 

[For The Popcorn]

You can be pretty sure in most countries, a plug designed for 120VAC isn't going to fit in a 440VAC socket. If the plug fits, it's probably going to be safe.