Electronic – ESD – Is it safe to connect yourself to an electrical outlet

antistaticoutletsafety

Is it safe to connect yourself to an electrical outlet?

Either directly or indirectly.

I would prefer to not connect myself directly to an electrical outlet, via (as I've heard) attaching a wrist strap to the middle screw of an outlet.

Though I am wondering about connecting more indirectly.

I am building a computer, that has a fully painted case. I have heard of a way to ground using the computer's power supply by:

Plug in power supply to wall outlet, turn power supply OFF, partially unscrew one of the four power supply screws (that hold it onto the computer case), then attach the anti-static wrist strap to the threads of the unscrewed screw.

Is that safe, in regards to indirectly connecting yourself to a wall outlet?

I would prefer a standalone ESD setup, that doesn't involve a wall outlet, however I have not yet heard of any ways to do so.

Thank you very much for helping with this.

Best Answer

If your plug has a correctly wired earth pin, then you can use that to ground yourself.

However before you do, it is worth noting that all reputable ESD wrist bands contain an embedded 1MOhm resistor. This is done primarily so that if you accidentally connect yourself to mains voltage (either through what you are handling, or through a wiring fault in the plug) the resistor limits the current that can pass through you, and so protects you from certain death.

I would suggest buying an ESD wrist strap. If you make your own, be sure to include a 1M resistor.

To be fair though even if you don't include the resistor, as long as you are absolutely sure you have connected yourself to the earth pin and nothing else, it will not do anything worse than touching the back panel on your PC (or the case of the PSU) because those are generally tied directly to earth on the outlet anyway. If touching your PC gives you an electric shock, consult an electrician.

As an alternative to the earth pin on an electrical outlet, you can also use things like metal plumbing pipes as these are typically earth bonded to the electrical system earth in the house, or go down physically into the ground.