This is a really simple question, that I don't know the answer to. If I'm going to make my own AC power cords from an old orange utility style power cable, white is hot, black is cold, and copper is ground, correct? And the smaller of the two plugs is hot, correct?
AC power...
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Cainester
Well-known member
That is edit --- (IN) correct.
If you look on your connector, the screws should be colored. The green is ground, the brass is black (hot) and the silver is white (neutral).
Caine
If you look on your connector, the screws should be colored. The green is ground, the brass is black (hot) and the silver is white (neutral).
Caine
pucho812
Well-known member
green is ground.
Scodiddly
Well-known member
It's backwards from the usual white/black speaker colors, at least here in the USA. Black = hot, white = neutral, green = ground.
This is the USA, though Canada is similar. Anyplace else may be different.
Once upon a time, all insulated wires were black rubber.
Then it seemed wise to identify the wire connected to the groundED side of the feeder. So we put white paint on that wire.
In theory, any groundING wire can be left bare. In practice, if you have plastic on it, it must be green.
Today the green/bare wire or screw is groundING, the 3rd or U-shape pin. The Identified groundED wire or screw must be White (screws are white-metal) and is the wide blade. Any other color (black, red, brass, chartreuse) may be Hot.
In practice, in the USA, the White and Black are switched-around about half the time (62% of the outlets in my house were wrong). And except for incandescent lamp sockets, it really does not matter. (You would really prefer the outer shell of a light bulb to be on the groundED White wire, but millions of lamps have hot shells.) Do the white/black any way that works. The essential thing is to get the green/bare wire connected from the U-pin to the equipment case. The white, black, red, chartreuse, etc wires must NOT connect to the case.
Once upon a time, all insulated wires were black rubber.
Then it seemed wise to identify the wire connected to the groundED side of the feeder. So we put white paint on that wire.
In theory, any groundING wire can be left bare. In practice, if you have plastic on it, it must be green.
Today the green/bare wire or screw is groundING, the 3rd or U-shape pin. The Identified groundED wire or screw must be White (screws are white-metal) and is the wide blade. Any other color (black, red, brass, chartreuse) may be Hot.
In practice, in the USA, the White and Black are switched-around about half the time (62% of the outlets in my house were wrong). And except for incandescent lamp sockets, it really does not matter. (You would really prefer the outer shell of a light bulb to be on the groundED White wire, but millions of lamps have hot shells.) Do the white/black any way that works. The essential thing is to get the green/bare wire connected from the U-pin to the equipment case. The white, black, red, chartreuse, etc wires must NOT connect to the case.
Mbira
Well-known member
The modern GFI outlets will not allow you to use white as hot on some outlets and black as hot on others. Black is always hot-or should be.
bcarso
Well-known member
A funny thing happened to me the other day. I had a toroid that was from an old multimedia product that I wanted to measure for open circuit voltage. I was a little preoccupied at the time and when I saw the white and black wires immediately thought Ah the a.c. input...
The other two wires were brown and blue, which should have given me pause---that, and the fact that the gauge of the white and black was rather on the heavy side.
When I pushed the white and black into the receptacle of my bench autotransformer there was a brief pop and bit of buzz and then the breaker on the variac opened.
I had unwittingly plugged the nominal 18V secondary into the 120VAC. Not only was the magnetization inductance way too low for 120VAC 60Hz, I was also getting over 800VAC on the primary---ouch! Fortunately I didn't kill the trafo, and the circuit breaker on the variac was resettable. And I wasn't holding on to the primary leads at the time either, and the DVM clipped to those leads didn't get killed by the brief exposure to >800VAC.
Anyway---when you see brown and blue on internal equipment wiring, including the conductors in a power cord, brown is mains hot and blue is neutral. This is the Euro standard now, and is being commonly adopted in the US as well. The safety ground, if present, is green with spiral yellow stripe(s).
The other two wires were brown and blue, which should have given me pause---that, and the fact that the gauge of the white and black was rather on the heavy side.
When I pushed the white and black into the receptacle of my bench autotransformer there was a brief pop and bit of buzz and then the breaker on the variac opened.
I had unwittingly plugged the nominal 18V secondary into the 120VAC. Not only was the magnetization inductance way too low for 120VAC 60Hz, I was also getting over 800VAC on the primary---ouch! Fortunately I didn't kill the trafo, and the circuit breaker on the variac was resettable. And I wasn't holding on to the primary leads at the time either, and the DVM clipped to those leads didn't get killed by the brief exposure to >800VAC.
Anyway---when you see brown and blue on internal equipment wiring, including the conductors in a power cord, brown is mains hot and blue is neutral. This is the Euro standard now, and is being commonly adopted in the US as well. The safety ground, if present, is green with spiral yellow stripe(s).
> Black is always hot-or should be.
Quite correct. (Assuming USA wall-wiring.)
> The modern GFI outlets
Yes. The GFI can know, and complain. I understood the question to be downstream of any GFI.
> getting over 800VAC on the primary
Unlikely. Probably a soft square wave of 100V-220V peak. Input primary current OTOO 100Amps. (Been there, done that, except the circuit breaker did not trip....)
> I had a toroid
Again: white/black is wall-wiring, and often used in US-market power cords.
But on transformers with only one primary, the primary is usually black/black. No assumption is made about which end of the winding is more earthy (since in many US homes with 2-pin plugs it will be wrong 60% of the time). On multi-tapped or dual-primary transformers, now you have to know which is which, so you won't find black/black as the primary. (In hindsight, finding white/black on a tranny should have been suspicious, but I know I would have lept to the same assumption.)
Quite correct. (Assuming USA wall-wiring.)
> The modern GFI outlets
Yes. The GFI can know, and complain. I understood the question to be downstream of any GFI.
> getting over 800VAC on the primary
Unlikely. Probably a soft square wave of 100V-220V peak. Input primary current OTOO 100Amps. (Been there, done that, except the circuit breaker did not trip....)
> I had a toroid
Again: white/black is wall-wiring, and often used in US-market power cords.
But on transformers with only one primary, the primary is usually black/black. No assumption is made about which end of the winding is more earthy (since in many US homes with 2-pin plugs it will be wrong 60% of the time). On multi-tapped or dual-primary transformers, now you have to know which is which, so you won't find black/black as the primary. (In hindsight, finding white/black on a tranny should have been suspicious, but I know I would have lept to the same assumption.)
bcarso
Well-known member
[quote author="PRR"]
> getting over 800VAC on the primary
Unlikely. Probably a soft square wave of 100V-220V peak. Input primary current OTOO 100Amps. (Been there, done that, except the circuit breaker did not trip....)
> I had a toroid
Again: white/black is wall-wiring, and often used in US-market power cords.
(In hindsight, finding white/black on a tranny should have been suspicious, but I know I would have lept to the same assumption.)[/quote]
The worst part of it is that I remembered after doing this that I had done it before, about five years ago, probably with the same variety transformer.
Yes, I guess the core saturation would have been pretty severe and the voltage on the higher-turns winding quite a bit lower. I was just pleased neither the the trafo nor the meter broke.
For a while I was afraid the variac was busted, as the breaker took quite a force to reset. But finally all was well.
> getting over 800VAC on the primary
Unlikely. Probably a soft square wave of 100V-220V peak. Input primary current OTOO 100Amps. (Been there, done that, except the circuit breaker did not trip....)
> I had a toroid
Again: white/black is wall-wiring, and often used in US-market power cords.
(In hindsight, finding white/black on a tranny should have been suspicious, but I know I would have lept to the same assumption.)[/quote]
The worst part of it is that I remembered after doing this that I had done it before, about five years ago, probably with the same variety transformer.
Yes, I guess the core saturation would have been pretty severe and the voltage on the higher-turns winding quite a bit lower. I was just pleased neither the the trafo nor the meter broke.
For a while I was afraid the variac was busted, as the breaker took quite a force to reset. But finally all was well.
