220V Outlet

Hi, I need to replace an outlet in a double gang box that has a 110V outlet on the left and a 220V single outlet on the right. The 220V had been put there to power a through-the-wall Air Conditioner.
My problem is in being unsure about which wire to connect to which side of the outlet. The 220 outlet had been removed and I didn't get a good look at which wire was connected where on the old outlet. The wire colors are pale yellow and white. I don't have a multimeter to check the wires just now.

I had first posted this question in the Wired Home Forum. A helpful reply from OldGuy suggested posting here in Electrical for more on grounding.

There is no bare or green ground wire. The outlet I replaced didn't have one and there are no stray wires that could be a ground in this box. Can I, should I add one?

 

If the 220volt outlet is the one being replaced and you only have 2 wires to work with it seems to me that both of those would have to be power (out of phase with each other). In which case it wouldn't matter which wire was attached to which side of the outlet...it would power the a/c unit either way.
A ground would always be advised for safety. You could try to take a ground wire from the box back to the main panel and tie in with the grounds there.

 

If putting 220v back JN is right, pale yellow sounds like you have pipe run in your house ,if so when you screw in the device it is grounded by the box through the pipe to box to screw connection. If you are turning 220v into 110v it is a new ball game get back to us.