[reilleyem]

My new K40 has a separate grounding lug...implying the need for a ground much better than you get through the 110v power cord. To me, that means drilling a hole in the floor and putting in a grounding rod since there are no pipes nearby. How important is having a good ground?

[alan_3301]

Unless you have wiring problems, your 110V ground should be perfectly adequate.

In my limited knowledge, the purpose of the grounding wire is to provide a path to ground to trip the breaker in the event of a short circuit.
This is for safety, to prevent shocks.

I would take the separate grounding lug as a notice to inspect the wiring of the whole device.

[reilleyem]

Alan, that's not right. The purpose of a ground wire is to have an alternate return path for electricity. The idea is that the power flows out to the device and returns through the common wire when working properly. Should the common wire be cut somewhere, then there's no path for the electricity to return to complete the circuit...until YOU touch the device. Then YOU become the return path...and that's not good. So, they add a second return path, called a ground, it provides added insurance so that you are NOT the return path, because by allowing the current to complete the circuit via the ground, you likely dealing with a short...and that means big current...which trips the breaker.

GFCI's trip when the amount of current going OUT doesn't equal the amount of current coming back via the common wire...a far better solution to protect you.

My concern regarding the extra ground lug...is that 20,000 volt amplifier that's inside this thing.

[alan_3301]

What did I say that you disagree with?

If the neutral wire is cut, that is essentially acting as a switch on the circuit.
This does not mean you will be shocked if you touch the device, unless the load side of the wire is shorted to the case.
If the case is properly grounded, that will trip the breaker.
I was aware of how GFCI's work, thanks.

If there is continuity between the external ground lug and the wall plug ground, then that will be enough.

[cinematic2]

Unless you have wiring problems, your 110V ground should be perfectly adequate.
In my limited knowledge, the purpose of the grounding wire is to provide a path to ground to trip the breaker in the event of a short circuit.
This is for safety, to prevent shocks.
I would take the separate grounding lug as a notice to inspect the wiring of the whole device.

The purpose of a ground wire is sensible in China where thay have 2-wire instalations.
You only need to check if all internal components (PSU, mainboard, laser PSU) are grounded as well as machine body.

[reilleyem]

Alan, yeah, you're right. I misread your post. Sorry.

And Cinematic2...thanks. That makes sense.

[Al_The_Man]

Not necessary to sink a round rod if you have a decent service ground conductor.
Just as important is machine bonding.
http://www.automation.siemens.com/do.../emv_r.pdf?p=1

see http://www.cnczone.com/forums/phase-...se-issues.html
Al.

[hub]

Ground is important because you want zero volts and amps between earth/ground (on where you are standing) and equipment chassis's etc..
If you can measure volts/amps between earth and equipment ground, then you need an extra rod.