It is details like that diagram that keep us coming back.

But the detail about the nondescript wires makes me growl deep in my throat. Even if you make your wires brightly colored with flashing lights saying GROUND! or HOT! someone will eventually get it wrong. If they're all the same, that day will come a lot sooner.

I'm a software engineer, not a real engineer, but I have still spent a lot of my life searching for and eliminating sources of human error before they ever come up, and it pays off every time.