Hi,
I am powering my arduino using USB cable that is connected to a wall socket with an adapter. This adapter provides 5V up to 2 Amps. Similar to a cellphone charger that uses USB.
My question is this: when I power my arduino using this USB cable, can I draw up to 2 Amps in the 5V pin of arduino or it could damage it? I know when I am powering arduino using VIN I can only draw at most 200ma from 5V pin, but since I am powering it with USB I think the limit should be the limit of my wall socket adapter, correct? Or am I wrong?
If you use a Uno you are limited by the 500mA fuse inline with the USB.
On a Nano you don't have that BUT, I would not put more then 500mA (and not even that) trough the PCB tracks... So best option if you want to use full 2A, cut the cable 
Thank you so much! Good point, but how could I "cut the cable"? From my USB port that I connect to arduino, which pin/cable is the 5V and which is GND? If I knew that I could get power directly from it, right?
To cut the cable grab snips, scissors or a knife 
In most cables red (sometimes a bit pink) is 5V. Black (sometimes a bit grey) is GND. BUT, always measure with a meter! Some Chines manufacturers just don't give a damn and use random colors 
Thanks! If I dont want to cut the cable, do you know which of the pins of the USB connector is 5V and GND?
Absolutely no idea why I get this as PM but okay. I'll happily forward it to the tread:
Paul__B:
batata004:
Thank you so much! Good point, but how could I "cut the cable"? From my USB port that I connect to arduino, which pin/cable is the 5V and which is GND? If I knew that I could get power directly from it, right?
Yeah, with scissors, but of course, you should have a full kit with wire cutters, soldering iron etc.
I collect USB cables from Garage Sales. "Thrift" shops can be useful, but tend to want more money per item. A proportion are faulty (wonder why they sold them, eh?) but given it is more likely to be the "slave" end, an excellent source of plug and wire. On the other hand, most of these come from branded products rather than Chinese junk (granted that even the branded ones are made there
).
The colours are mostly correct - Red, Black, Green White, being 5V, Ground, D+, D-.
And mostly correct? Isn't that exactly what I said? 