I'm building an electric RIMS system from an old barrel-style keg. I picked up a 4500W 240V HWD element from Home Depot, and built a 1" copper tube housing around it to let wort flow by.
My understanding from various homebrewing forums I browse is that if I run the element at 120V, I should reasonably expect to get about 1100W of heat from the element (1/2 the voltage equaling 1/4 the wattage), effectively making the element a ULWD type good for not scorching wort, but I'm scratching my head about that. My understanding is that Watts = Voltage X Amperage, which seems to imply that my 4500W element at 240V would be 37 amps at 120V, which could cause all sorts of unpleasantness with my household power circuits.
So I have three questions:
- Why would 1/2 the voltage equal 1/4 the wattage,
- is this enough wattage to maintain a mashing temperature for up to a 10 gallon batch in a stainless steel kettle, and
- would I blow a 15A GFCI circuit by putting the March brew pump on the same line?