A duplex outlet is 115vac.
Electrical wall outlet having two plug receptacles.
A 120 volt duplex outlet is the main type of outlet for residential outlet system. The wires are typically white and black, and there should only be two of them.
Black, white, and copper.
A duplex socket outlet is a type of electrical outlet that features two sockets in a single unit. This design allows two devices to be plugged in at the same time, making it convenient for powering multiple devices in one location.
2 Amp
No a 208 volt outlet does not need a neutral. 208 volts is the line voltage between any two legs of a three phase 208 volt system.
it is the pressure difference between inlet and outlet of pump.
Zero, or very close to it. If there is a large neutral current flowing, voltage drop on the neutral leg could cause a volt or so to read between the two. If you read full line voltage, the outlet is wired wrong!
Call an electrician.
A line outlet is where the electrical power enters a device, while a load outlet is where the power exits the device to be used.
There is an open circuit on neutral. You should have power between hot and neutral, as well as between hot and ground. Note well, however, that you should not pull any power between hot and ground, because ground is not intended to be a current carrying conductor - it is only there as a protective earth ground in the case of fault. You can not easily tell, at the outlet, if neutral and ground is reversed - you need to pull a load and then double check with a clamp on ammeter at the distribution panel.