This is a box that will take 4x Banana Jacks, to be wired together with thick gauge tinned bus wire, and then ran out the box via a (also adequately thick gauge) cable which can be attached to a ground point, either via a wall outlet or metal piping.

Notice: I am not a professional electrician or EE, just a hobbyist. By no means do I condone the use of this device anywhere near line voltage, or with anything that could conceivably be considered "high voltage" in any regard. Use yr noggins!

V1 doesn't have a hole for the cable (my mistake, but might be helpful to someone)