This photo shows how to eliminate floating ground on a cheap switching mode power supply. The green wire connect the body to the negative terminal. Some said it will help to eliminate the noise too. But i didnt notice that.
Mine was a 12v 30amp. Price was under 100 ringgits. I use this power supply since last year. I'm not afford to buy expensive brand such as diamond, mfj or astron.
It has a cooler fan, but as long as i remember, the fan was never rotate eventhough i am using it with a hundred watts transceiver for a couple hours.
You can buy this type of power supply on ebay too.
I'm still happy with this cheap power supply unit.