How to remove ground pin on power cable

It may help everyone to think about two separate advancements that have occurred in home wiring. I’m rusty on the full history, but if you’ve done any upgrades you may have felt like an archeologist, and learned about a few things.

1 - The invention of the polarized plug. When this happened some makers, like lamp makers did in fact use this as a ground. So long as the impedance is near zero, no problem.... but if that lifted for any reason like a loose wire, corrosion etc. voltage at the lamp could happen.

2 - The separate ground conductor which evolved over a few iterations, not sure exactly the timing but:

• Originally no ground wire needed when metal conduit was used. This is no longer acceptable. Conduit not considered reliable.
  
• Originally you could wrap a conductor around any old place to ground outlet boxes. Now must use special fine thread green screws and tabs.
  
• The addition of the appliance safety.
  

The point to #2 here is that much has evolved from the early 2 wire system to today’s 3 wire. It didn’t happen until there was a need. Each of these advancements was made because the previous state of affairs cost too many lives and homes.

Edison didn’t come up with these ideas. They were created out of necessity.

Today gear with a metal exterior must be grounded OR be double insulated. This is why my plastic body blender has no ground, but my stainless coffee pot does.  I think there may be some exception for gear with outboard, low voltage supplies (i.e. wall warts) too.

The reason, as I recall, for neutral and ground being separated has to do with Ohms law.

Neutral is a working conductor in the sense that it SHOULD normally carry 100% of the current the hot does. So, 15-20 amps in a typical residential application.

Due to many factors, the impedance of neutral can become significantly non-zero.

15 A * 0 Ohms = 0V

15 A * 5 Ohm = 75 V

etc. etc.

So it is quite possible, if not probable that neutral can be non zero. Now imagine if that the ground wire no longer exists (as in old homes/appliances), but the chassis of your equipment is bonded to neutral (old washer/dryers). See the problem? You now have gear which can develop a significant shock factor by touching it. Happened to me with an
old dryer once. :)

The entire point of a safety ground in appliances is to have any voltage which accidentally touches the chassis to drain to ground and hopefully blow a fuse or breaker.

Of course, faults can happen in the ground conductor as well, but operationally, if the ground develops a high impedance, it’s not going to normally develop a voltage because current = 0.

This part is kind of important:

Because each panel can introduce a new impedance problem, the neutral and ground must remain unbonded except at the service panel. The service panel is the first one after the meter. So, if you add subpanels, you run 4 conductors. +120, -120, Neutral and Ground. One trick here is that the ground may form a loop. You don’t necessarily have to pull the ground from the panel....but that leaves open the possibility of a future contractor not knowing this, so don’t.

This concludes my Ted talk.

From some posts here, apparently many homes continue to be grounded via the water line.

This hasn't been acceptable ( up to code ) in decades. I mean, there's no requirement to fix this, generally, but you may no longer rely on copper pipes for new construction and upgrades.  You MUST use grounding rods (sometimes more than 2, depends on soil conditions) for the electrical ground and they must connect to the neutral only at the service entrance. Any sub panels must maintain the ground/neutral separation.

There are some requirements to ground copper pipes, which I forget why, but you don't use them as electrical safety grounds. Not only are the connections iffy, but with modern water pipes using mostly plastic it is quite easy to find an older home which has plastic in the middle.

@builder3

https://www.thespruce.com/water-heater-bonding-wire-4125747

I do have to say it is fishy as hell for a manufacturer to use a 3 pin IEC connector, with a working ground and say it's removable.  As I understand it, to not require a ground pin you need the powered section to be double isolated.

I have a Hsu sub which has a 2 pin IEC connector. There is literally no ground pin there, and I can therefore use 2 or 3 pin IEC cables. That's the correct way to do this.

Disassemble the sub side connector and remove the green/center wire from the end.  I'd wrap it in black tape and reassemble it. This will preserve the value and let you reverse it.

I suggest the sub side because if the cable is shielded, you'll want to preserve the ground at the wall side.