I am overstocked on IEC cords. (01)

I cut the female end off and use them for line cords. The stripped outer jacket goes into my spaghetti stash. Note that the wires are only soldered at the very tip to keep them from unraveling Do not tin the whole end of the wire. Solder: "cold flows". That means it flows like water but very, very slowly. If you tin the whole thing and tighten down a screw on it, in a year or two the solder will flow out and you will have a loose connection. (02)

The next step is to break the breakaway connections on both sides of a duplex outlet to form two completely separate outlets.

Connect the line cord as shown - hot to a switch - Neutral and ground to the bottom outlet. (03)

Add a jumper from the switch to the hot side of the top outlet and a jumper from the neutral side of the top outlet to the hot side of the bottom outlet. (04)

Mount it in an electrical box . This is one of mine above the workbench (05).

 I have a selection of light bulbs to use in series with the test (Bottom) outlet.  (06).

I select the largest one that will not blow the fuse in the item under test. It will light brightly if the short still exists without blowing another fuse. flipping the switch off removes all power while you try to locate the short. Flip the switch on to test - a bright light indicates you have not fixed it. A dim light means you probably found the short.

Each  bulb is ready to plug in the top outlet. (07)

To rate each bulb I use a kill A Watt from Harbor Freight. You will fine many other uses for it too. (08).