Hey squeeky,
Scoates diagram looks like a herms system, mine is a little simpiler.
I do have 2 heating elements, the one for the mash tun is 110v and the boil kettle is 240v. The mash tun element is in a copper heat exchanger so when the mash tun is recirculating the heat exchanger can be turned on to reach mash temps. The boil kettle has a 4500W 240v element mounted directly in the bottom of the keggle. I actually finished getting the element in the keggle this evening, Ill get some pics of it once it is cleaned up.
Side note- literally smoked my old B&D drill using a large unibit to cut the element hole. Got a new 7.8A 850rpm VSR DeWalt to replace it.
Edit: Sorry, I wasnt clear on how I was providing power. I am using 110 from the recepticle/lighting ciruit for the house and the water heater 50A 240v Circuit. going to set the Water heater up with a plug so I can unplug it and plug in the brew rig.