Neutral - in non-scientific terms (electrons and atoms), the
neutral wire is the "
return" path for the electrical
current serving any given device.
Thanks. I did somre more reading on it and this closely matches that. I might say that the
neutral wire complets the
circuit, rather than that it is a
return path, since this is AC we're talking about.
Current flows both ways through the hot and
neutral wires. What I didn't take into account is that, when all is as it should be,
no current flows through the
ground wire, even though it is electrically connected to the
neutral wire (but not in my
mixer, be that audio or kitchen).
The purpose of a
ground path to earth (
ground) (in layman's terms) is if somewhere in the electrical path/device/
wire/
etc electricity is getting lost somewhere-and not making it's way back to the
neutral/
ground bus bar at the
tie in,
breaker panel,
etc. It provides a safe path for electrons instead of taking the shortest path to
ground, which is what, by nature (science, actually) they want to do. The shortest path could be a priest, performer, or technician, as mentioned above.
I see. So, if the hot and
neutral wires were always intact, and a complete path from one, through a device, to the other were always to exist (or, were not to exist because the path were to be safely interrupted, with, say, an "off"
switch), the
ground wire would never be needed. But, if the path is interrupted, and the hot
wire makes contact with the chassis of a device, the
ground wilre completes the path back to
ground, and in a very low-impedance way, which: 1) means very little
current will flow
throw anyone touching the chassis and also in contact with another low-impedance path to
ground, and 2) will pull so much
current that it will trip a
breaker.
From Richard Cadena's article, I gather that a
GFCI adds two more protections: first, if the
ground path itself is not effective, either by reason of it being open, or not low-impedance, a lot of
current might flow through a person instead of back to either the
neutral or hot
wire (depending on which
phase of the AC cycle we were in), it will detect this and open the
circuit, something a
breaker might not do if the total
current being drawn is still below the
breaker's limit and, second, will do it faster than a
breaker would anyway.
PSS- the fact that the lights being at 50% created a louder hum could be a variety of issues. Grounding, unshielded lines run in long, close, proximity to AC lines or lighting lines,
etc. Hard to diagnose without knowing more details.
Yeah, one step at a time
. Now that I know a
bit more about what a
ground wire does, it's probably time to gird my loins and study up on
ground loops. The hum we're getting may be from one of those, or something else (or both). Our performance
mixer plugs into a
channel on a rack
mixer that is quite close to the dimmers. I wouldn't be surprised if having audio lines that close the dimmers isn't, itself, a bad idea.
I read up recently on MADI, a synchronous digital audio
protocol. Gosh, I'd love to work in a
house that used
that. I can see how it wouldn't cure every hum problem one might
face, but it sure does seem to solve a lot of problems, hum and others, and has a certain logical elegance I like. Also, as it is a digital
protocol, not an analog contraption, I can understand it better
.
