Need advice on how to fix the height etc issues as per mfg recommendation

[Jadnashua]

A GFCI receptacle does not use the ground at all. It compares the power going out the hot side to that coming back on the neutral, and if they differ by more than about 5ma, it trips. Those 5 milliamps must have found another path to ground, possibly going through you, and then it trips to remove the power.

Now, in the scheme of things, in order of increasing overall safety it would be:
- two wire receptacle
- two-wire polarized receptacle
- grounded 3-wire receptacle
- two wire plug with GFCI protection (and maybe an AFCI)
- 3-wire with GFCI
- 3-wire with GFCI and AFCI

The house I grew up in was originally wired with BX, that MIGHT have provided a ground when it was new, but certainly did not after a bit of age and rust. Metal boxes today should be grounded, but they often weren't, at least in a reliable manner, ages ago. That meant that using one of those adapters with the pigtail intended to go on the cover mounting screw were often useless to anything that really wanted a ground.

I replaced the first receptacle in each circuit that needed it with a GFCI. That was cheaper than replacing the breakers, which might have made the discovery of the first in each chain as long as you don't have to pay the labor of someone doing it for you.

Some devices expect a real ground to perform their full functionality, but for safety, a fully functional GFCI means you should never get electrocuted. Without a ground, you might not trip the breaker or blow the fuse, as over-current is not something the GFCI monitors.

 

[wwhitney]

A GFCI receptacle does not use the ground at all. It compares the power going out the hot side to that coming back on the neutral, and if they differ by more than about 5ma, it trips. Those 5 milliamps must have found another path to ground, possibly going through you, and then it trips to remove the power.

Nice explanation, except that the bolded word should be "the source". That path back to the source transformer may or may not involve going through a bonding conductor (one type of ground) or the earth (another type of ground). Typically though it does.

Cheers, Wayne

 

[Sponsor]

 

[Jadnashua]

Yes, power needs to flow in a complete path from and back to the source through a device, powering it in what is called a closed circuit. In the way the US does things, you do not actually have 120vac coming into the house...you have 240vac, with a center tap on the secondary of the transformer called neutral. A characteristic of a transformer is that when one end is positive, the other end is negative, so if you go across the whole thing, you get 240vac. But, if you go halfway across it, sort of like a dimmer, you get half of that, or 120vac. For safety reasons, the neutral is connected to ground, but ground is not needed to complete the circuit, but becomes an alternate path to completing the circuit, or to provide a path to blow a fuse or trip the breaker if there's a short circuit in the system. Details, details, but it all works! A GFCI detects that the power is not making the intended complete circuit. SOme of it is leaking off to ground. As designed, ground is there only for safety, and should never have current on it. https://theengineeringmindset.com/120-240v-split-phase-us-can/