In my experience, if you don't ground your box, there would likely be a float voltage across the transformer-less SMPS, which may spread to various parts of the box and any other device wired to it.
Then, if you are sweating or wet, and come in contact with a grounded object and the float voltage at the same time, enough current may pass through your body to, well, kill you.
When I said 'in my experience' above, I meant only the first part. I know you people realized that.
Well, it's pretty unlikely that the PSU is transformerless. After the primary side rectifier and the primary FET there's usually a high frequency transformer in order to lower the switched voltage before recifying it again to +12V. Perhaps a forward or flyback topology type (or any of the other common ones). Theoretically you could get rid of the transformer but that would make the duty cycle so low that it would be difficult to regulate the output voltage. Another reason (or more of a bonus) for using a transformer in the PSU is to electrically isolate the input from the output.
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In my experience, if you don't ground your box, there would likely be a float voltage across the transformer-less SMPS, which may spread to various parts of the box and any other device wired to it.
Then, if you are sweating or wet, and come in contact with a grounded object and the float voltage at the same time, enough current may pass through your body to, well, kill you.
When I said 'in my experience' above, I meant only the first part. I know you people realized that.
Well, it's pretty unlikely that the PSU is transformerless. After the primary side rectifier and the primary FET there's usually a high frequency transformer in order to lower the switched voltage before recifying it again to +12V. Perhaps a forward or flyback topology type (or any of the other common ones). Theoretically you could get rid of the transformer but that would make the duty cycle so low that it would be difficult to regulate the output voltage. Another reason (or more of a bonus) for using a transformer in the PSU is to electrically isolate the input from the output.