so that both the positive and negative would have to short the enclosure at the same time.

That also causes no shock hazard. It either blows a fuse, causes the power supply to shut down, or burns something until the short is gone.

Bob

 

That also causes no shock hazard. It either blows a fuse, causes the power supply to shut down, turns inti a space heater, or burns something until the short is gone.

Bob

 

I see now that it may be better to leave the enclosure floating rather than ground it, so that both the positive and negative would have to short the enclosure at the same time.

Yes as that is what it comes down to.

Ron

 

Hello - I'm creating an LED device and I'd like to have a good understanding of grounding/safety so I don't accidentally harm my users!

I'm powering my device with an AC/DC wall mount adapter that outputs 20V which connects to a barrel jack on my PCB. I'm using an LED driver as well that outputs 700mA constant current. My LED itself has a forward voltage of 17.2V at 700mA at test temperature (85C).

I connect to my LED with wires off-the-board. I'm using screw terminal blocks on the board itself as this seems to be the most secure connection. And I solder my output wire leads to the LED for a secure connection.

However, I'm using aluminum for the light stand itself and I'm worried one of the LED hot wires could potentially become disconnected from the LED and then make a connection to the aluminum enclosure, giving it a voltage potential. And then when a user touches the device, they could become shocked.

How can I make sure nothing catastrophic can take place? My understanding is that to ground a device, a wire from the metal enclosure should be connected to the ground plug in the AC plug, so if the enclosure gains a voltage potential, it will be dissipated through the ground wire.

However, in my case I'm using the AC/DC wall mount adapter so I'm only dealing with DC within my device.

As you can see, I'm a novice so any tips or pointing me in the right direction would be much appreciated.

The solution to avoid any possible shock hazard is quite simple. Use a medical grade DC power supply, available from DigiKey and many other sources. That will assure that any leakage current is very small and non-hazardous. The 20 volt output will be totally isolated from the mains.