[aaronmdjones]

Careful application of a box cutter for the outer sheath followed by something resembling a scotchlok connector for line and neutral.

Edit: If the machine is plugged into a power bar / power strip / whatever you want to call it, this is much easier still: Plug the vampire UPS into the power bar as well, wait for it to sync up to the grid, and disconnect the bar from the outlet. The UPS continues to feed power into the bar and thus keeps the machine powered.

[pests]

Power strips make this easier of course, but every outlet usually has two plugs and most* of the time they are wired together. You just need to plug into the other plug.

* In case they are split for whatever reason (switched plug, different circuit) whatever, just take off the faceplate, pull out the outlet, and now you have direct access to the screw terminals and copper wiring on the outlet. You could wire into the plug using the second set of terminals or via the other connection method (one being the screw terminals, the other being the "insert into the hole" depending on which is used) and take the whole outlet with you.

[aaronmdjones]

That would apply in North America yeah; that wouldn't apply over here (UK).

The insulation on plug pins prevents you pulling the plug far enough out of the socket to use a plug pin capture device; if it's far enough out of the socket to expose the uninsulated portion of the pins, it is no longer far enough into the socket to be receiving voltage, and you've just interrupted the power, which is precisely what you don't want.

The design of our wall sockets is such that there is no separate faceplate assembly; you'd have to take the entire socket off of the wall. Excepting some exotic sockets (like the MK Logic Plus Rapid Fix), there is only one recessed insulated screw terminal for line and neutral and no holes to push conductors into [1], and loosening that screw to put another conductor in would also risk interrupting the power.

Furthermore, most sockets are on ring circuits, and removing the socket from the wall creates a dangerous potential for an overcurrent condition on the now-incomplete ring, which the breaker will not respond to, as it can't know that the ring is no longer complete.

In order to safely do socket surgery in this scenario, you'd first have to connect both lines and both neutrals together using something like a scotchlok connector. Then you can cut one of the line and neutral conductors from those to the socket. Finally, you can crimp onto the flying socket line and neutral from the vampire, and then cut the other line and neutral when the UPS is ready to feed the socket. This leaves exposed mains-potential conductors behind the wall which should be capped off by some form of scotchlok or crimp connector for occupant safety, and an exposed mains-potential conductor which should be capped off for officer and technician safety. [2]

I dare say this is more involved and riskier than simply carefully cutting into the equipment power cord. Also, good luck finding enough slack conductor behind a wall socket in order to pull this off.

[1] https://media.screwfix.com/is/image/ae235/15747_A1

[2] https://i.imgur.com/JCNm9CX.png

[pests]

Oh interesting. Do you have outlets with two plugs that are internally wired together?

[aaronmdjones]

We do, but that doesn't help you much if e.g. they have two computer systems plugged into the same double socket outlet and you want to seize both of them without powering them off, or you fear that the computer system plugged into one socket will react badly to the loss of power of whatever device is plugged into the other one alongside it. Almost all of our sockets are also switched, so you're playing with fire every time you put your hands on it -- you might knock the switch and kill the power to that socket just by trying to take it off of the wall.