Black to Brass

[Denny]

better than in the middle

that would be the motor homes, on the lane and a half roads, in the mountains


I miss having a motorcycle

[s1m0n]

Of course, I understand that it doesn't matter whether the ground plug is on the top or the bottom of the 3-prong configuration, as long as all of the wires are connected correctly. I'm not too worried about the electricity coming out upside down. To me, it is merely a matter of convention. Similarly, a wall light switch is on when switched upward and off when switched downward. You can easily wire it the other way, but that is not the standard way of doing it. For faucets, the hot water goes on the left and the cold water on the right.

It's convention otherwise, but many of the wiring conventions are stupid. The advantage of third prong up installation is that this way anything falling down the wall onto a loose plug can't hit a hot wire.

I saw a lecture from a former contractor who'd become a guru of senior-friendly housing standards, in which he explain that we all expect sockets to be where they (in NA, about 14 inches or so from the floor) because back when the nation was being electrified, everyone did as they thought best, and that offended the sense of uniformity of someone at the carpenters' or electricians' union. The union opted to tell apprentices to stick sockets at the height of their hammers from the floor, so henceforth they'd all be uniform. And 80 years later we all still do it, despite this being a position that a great many seniors and the disabled can't reach.

[UncleChuck]

You can still think of it as a river. The hot wire is the source, and the cold wire is the drain. Just like a pipe. It doesn't really matter what the electrons are doing. AC is just a different kind of "juice".

We drive in the middle, head down, fast. You can take the boy out of Texas, but you can't take the Texas out of the boy.

-=chuckt=-

Edit: I don't remember if the hot is the black wire or the white wire. Green is ground.

[s1m0n]

Hot's black, but only if you can be confident that everyone who's had a go at your circuit followed the convention religiously, and was working with wire new enough to distinguish black from white. If anyone along the way guessed wrong or didn't care, it could be either way.

[hans]

Hot/Live is red here. And black is neutral. Black is live in Germany though, and blue is neutral. Then we get brown as live as well. As you say, Simon, never be too sure! If you take a light switching circuit apart, the colour coding may be mixed up anyway. And also a neutral wire may actually carry live if a load/appliance is switched on.

[I.D.10-t]

Stupid question, but can a multimeter verify the difference?

[hans]

If you want to check if a wire is live/hot, in a domestic circuit (max 240 Volts AC), a mains test screwdriver might be enough. They are usually insulated to 500V, and light up when the tip touches a live wire, while your hand touches the contact on the end of the handle. It detects potential to ground, which is all it needs to give you a shock if you touch the wire.

(I am talking European voltages here)

[Denny]

thats yes on the multimeter
using volts and
only if you can be sure of your ground

[UncleChuck]

thats yes on the multimeter
using volts and
only if you can be sure of your ground

Be sure you set the dial to read the voltage "high", rather than "near", or you could burn up your meter before you can blink. In other words, if you expect to measure 240V, set the meter to read on the 1000V scale, not 200V. Most meters have a AC and a DC scale. Be sure to use the correct one.

[Denny]

so how many have ya melted Chuck?

[UncleChuck]

so how many have ya melted Chuck?

More than one!

[chas]

North American household current is 110v 60 hz AC. Historically, plugs were like this:



Which work either way you stick it into the socket. In the sixties or early 70s we got three-prong plugs like these



The round prong is a dedicated ground wire. This is still in use for higher power and utility devices.

In the 80s we started getting these:




..where the prongs differ because one is grounded. They're not as safe as a three-prong plug, but they're safer than option one because appliances that have a polarized plug are designed so that any short is supposed to go straight to ground via the neutral wire. It made no sense with my reversing river model, because with it each wire is equal. Like a lot of people, I did my share of cutting off the wides prongs to adapt new equipment to older plugs and extension cords. My new model says that sometimes the hot wire pushes and sometimes it sucks, but it is always the one in charge.

The difference between the neutral and the ground is that the ground is grounded in your house. The neutral is grounded somewhere, but there can be a substantial and variable voltage between the neutral and ground. When I was in graduate school, some boneheaded professor, for reasons that were never apparent to anyone presumably including himself, tied the neutrals in his lab to the building ground. It took several of us with sensitive equipment a few days to figure out that the building ground had been floated, i. e., was no longer earth ground. So for some time there were about half a dozen pipes pounded into the ground outside various labs, and we had to run copper braids from our labs out to our own "personal" grounds and electrically isolate our equipment from the building.

[Denny]

so how many have ya melted Chuck?

More than one!

I was more into diodes.....

[UncleChuck]

so how many have ya melted Chuck?

More than one!

I was more into diodes.....

I like the way they SNAP when you let the magic smoke out. But for real fun, try an electrolytic capacitor!

[Denny]

I had to give those up....

scared the natives too much


tube theory, Memphis, 1969