Typically, the black wire is hot, and white is common/neutral. I would double check this if yours is opposite. On most plan wall switches, only the black (hot) wire is connected through the switch, with the line coming from your house service, and the load going to your light. Sometimes if new enough, the switch is connected to ground as well. And if the switch is a lighted switch, the common will be connected as well.

If you want the outlet to always be hot, then you need to use the wires from the line side, and if you want it switched, they'd connect to the load side of the switch.

Can you post a pic of how the switch is wired, and what other wires are in the box?

It sounds like the switch is wired as a switch loop, which means you don't have a full set of wires at the switch. With a switch loop you have the equivalent of two black wires at the switch, and the white wire should have been taped or colored black on the end to indicate that it was functioning as a black wire.

At the light they would have connected the incoming black power wire to the black wire running to the switch. Then they should connect the black wire on the light to the white wire running to the switch. This means the switch has been inserted between the power feed and the light, and it just switches the black power wire running back to the light.

Bottom line - you can't pull power for your receptacle from a switch if its wired as a switch loop.

Bruce

> The best I can get is when I turn on the light switch the light turns on,

> but the outlet is off. And when I turn the light switch off the outlet
turns on.

It's kind of academic anyway since this won't work, but you might find it interesting to know why not.

The receptacle you wired across the switch that seemed to be on when the light was off wasn't really. More like maybe "half-on."

When the switch is off, the receptacle is in series with the light. That means that the electricity has to go through the receptacle to get to the light (and vice versa). As a result, the light and anything plugged in divide your house's 120 volts between them.

How they divide the voltage depends on which one wants more power. A neon receptacle tester uses only a tiny bit of power, so if you plug one in, it will get all the voltage and leave almost none for the light. Thus you'll think the receptacle is live. But if you plug in an appliance that uses any significant amount of power, say 100 Watts or so, the light will go on (though it may be dim), and the appliance won't get the right voltage.

Depending on how much electricity the appliance is trying to use, either the appliance won't work at all, it won't work right, or it might even be damaged.

So the bottom line is that you'll have to pull a new cable to the box to feed your receptacle.

Really appreciate all the responses. Well I just wasted an afternoon today but learn some new things in the process. I’ll move on to plan b now.

Your original post leaves out some important details: When you connected the receptacle to the wires in the switch box, how did you connect them? Plug a lamp with an incandescent bulb with a wattage similar to that in the existing light. If the switch is off, then the two bulbs are in series, each getting about 60 volts, and they should glow dimly. If you turn on the switch, you are putting the full 120 volts into the existing light and the receptacle is shorted out. If this is what happens, then this confirms what Bruce and DavidR said.