Timeline for Why do we need an earth wire?
Current License: CC BY-SA 4.0
9 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Oct 25, 2022 at 2:00 | comment | added | J. Murray | @kwdash $\uparrow$ Done. | |
| Oct 24, 2022 at 19:02 | comment | added | kwdash | Question adequately answered😅 @J.Murray could you post that as an answer so that I can accept it? Thanks! | |
| Oct 24, 2022 at 18:08 | comment | added | John Doty | @kwdash Well, in my youth, doing dangerous things with electricity, I once blew a 15A fuse by accidentally connecting "hot" to a water pipe ground. Then I went to MIT and got to do really dangerous things with electricity ツ. But that was a long time ago: standards are higher these days. | |
| Oct 24, 2022 at 18:03 | comment | added | John Doty | @J.Murray And faults aren't uncommon. A couple of weeks ago I had to replace a fridge that was tripping a GFCI. | |
| Oct 24, 2022 at 15:36 | comment | added | RC_23 | kwdash, that's exactly right, but the whole point is that without the grounding wire, the only path to ground is through the person. A fault means that the live wire touches a metal part of the appliance that neutral does not touch. With the grounding wire as a safety feature, majority of current from the live wire into the metal appliance will be routed thru the low-resistance ground wire, and very little will be routed elsewhere (e.g. thru the person). The goal is that after a fraction of a sec of this high current, a fuse or breaker will trip. | |
| Oct 24, 2022 at 15:21 | comment | added | kwdash | @JohnDoty That's the thing, how low can the resistance be? A quick Google search seems to show that dry bitumen/concrete has a pretty high resistance (although that of soil is pretty low), and I can't find any good sources on the resistance of a typical electrical device. | |
| Oct 24, 2022 at 15:14 | comment | added | John Doty | @kwdash Maybe, although you might be surprised at how low the resistance can be. And while the neutral isn't supposed to be "hot" relative to ground, simple, common wiring faults can make it "hot". | |
| Oct 24, 2022 at 15:06 | comment | added | kwdash | Surely this would be a path of higher resistance than flowing through the circuit though... | |
| Oct 24, 2022 at 14:11 | history | answered | RC_23 | CC BY-SA 4.0 |