As an aside, I can't see anywhere in your photos for an earth attachment to your kettle. You need to make sure that, however you do it, there is a solid connection from the earth wire of your power supply to the kettle (and anything else in your brewery which is connected to mains and has a metal chassis, or metal parts which protrude through a plastic enclosure). When an element fails it will usually go open circuit, but in some cases it can short itself to the sheath. In this case, if the chassis is earthed it will just blow the fuse or trip the breaker, and not work again until you replace the element. But if there's no earth, all it does is make the kettle/chassis live, at close to 240V (depending on how far down the element the short occurs). Next time you touch it, probably barefoot on the ground, in a puddle of wort, or with some other path to ground, you get zapped.
To earth it, there's a few creative ways you can go about it. Ideally I'd say weld (or have welded, depending on how you got your socket done) a bit of thread onto the kettle beside the socket, crimp a ring terminal of the same size onto the earth wire, and fasten it to that thread with a nut, covering the whole thing in some sort of plastic junction box. You might also consider using a much larger ring terminal, and putting it around the element thread between it and the socket, though I don't know where you'd get a ring crimp of that size. Have a fiddle with it and work out the best way to attach it, and then keep all your connections neatly insulated. You might be able to glean some ideas from looking at your water heater, and maybe scrounge appropriate parts from one discarded on council cleanup day.
