Ok, here is what I think may be what you need.
Required:
1 POT/variable resistor.
1 pushbutton swith.
1 power NPN transistor.
1 power PNP transistor.
I can't attatch a picture because just now I can't get the drawing thing working.
Basically:
Power supply
Emitter of PNP transistor.
Base of PNP connected to pushbutton switch.
Other side of pushbutton swith connected to Collector of PNP transistor.
Collector of PNP connected to Pot (stationary part) and Collector of NPN transistor.
Base of NPN transistor connected to to the moving part of the pot. More on this later.
The other "stationary part" of the pot is connected to the Emitter of the NPN transistor.
The Emitter is also connected to the "LOAD".
What is going on - as far as I can work out:
At normal everything is not conducting.
The POT needs adjusting so with the load connected it turns on the transistor.
To test, you will need to keep the press button pressed.
At one extreme of the POT it should turn off because the base current would be too low to turn on the transistor if there was a short. This is where the "Load" comes into the equation.
As it isn't a short, there will be a voltage drop over it and so with a bit of tweaking, the pot will set the trip voltage to turn off the NPN transistor. So from there let's look at the PNP. It is turned off because of the base being not connected to anything and so there it would not be allowing any current. When the button is pressed, it takes the base low and it turns on. In doing so, the base current starts to flow and the NPN turns on. The load is active. If there is a short, the base current on the NON stops and so the NPN turns off. Doing so the PNP is turned off because its base it taken high.
Hope that works.