I have a vantec "ion" 400w power supply. It has a normal wall-outlet type plugin on the back for extra accesories. If I plug something into this, will it draw power from the psu, or from the wall? I am interested in plugging my water-pump into this, so I won't need to purchase a relay, but I don't think the power supply can handle the pump and everything else in the case. It would seem foolish to have the plug-in draw power from the psu in any way, I just want some assurance its a safe thing to do.

It is an AC Outlet so you can plug in a pump in to it.. it doesnt draw from the PSU.. it will draw from the 120VAC inlet
Now will it be on constantly or turn on when ur PC is on... I have no idea..

Usually those two plugs (inlet and out) are wired together, if the outlet stops when the ps goes off i never tried but i guess it should.
And yes it draws from the wall outlet not the ps

Yeh when you turn off power from your computer it also turns off the outlet power from the PSU. Those PSU's with 2 ports in the back are fairly old hat arnt they?

those PSU were meant to turn on a monitor when you start up your comp.a monitor is a big power eater and the older PSU's with 250W only would be dead if the monitor sucked from the PCU directly
your safe doing that...

there are newer PSU's that come out with two connections...but i haven't seen them around in my region

i was jus gonna say arent those psu's with the two connectors a really old psu to help the monitor along but you beat me to it