In the electrical appliance manufacturing industry, the following IEC protection classes are defined in IEC 61140 and used to differentiate between the protective-earth connection requirements of devices.

Character Oc It was art Then it was this Class 0

But it turned out like this. I really suck. Suck. Suck. These are characters from Class Z(ero) =...

"I wanted very much to learn to draw, for a reason that I kept to myself: I wanted to convey an emotion I have about the beauty of the world."
Richard Feynman
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