In theory, there is no problem whether the 36-volt USB can be operated on power. Industry regulations below 36 volts is a safe voltage, but there is a problem that refers to the human casualties not only the level of voltage, but also the size of the instant current, if the instant current is very large, you in contact with the live for a long time, it will cause instant damage to people. So it's best to operate without power.
USB ports are standard DC V voltage, have not seen the output of AC 36V. There is a multi-functional AC 220V adapter strip (strip board), with a USB jack, but in the strip is equipped with 220\/5V switching power supply, such a strip of course to connect to 220 power supply, if you do not understand it, look at the manual, or open the strip to see it.