It is because the nec standard.
If this is a home wiring question and the wires are black and white then black is Hot and white is Neutral. If you also have a red wire, it is the other hot wire, and either the black or the red wire to the white one would be 120 volts, and red to black would be 240 volts.
Assuming the wires are the correct gauge for application and breaker you use black and white wires as hot. Put red electrical tape on each end of white wire and connect red and black to the breaker output and bare wire to ground lug in panel. At receptacle connect black and red to hot contacts and bare wire to ground lug.
Load (or hot wire, usually black or red), Neutral, (white), and ground,(green) wire.
On a 3 wire dryer cord there is no green wire. The white wire coming from the outlet is connected to ground or the green screw. The black and red wires are the hot wires.
You will have to run new electrical wire or a single ground wire back to the panel (though the former is highly recommended). A GFCI outlet will cut off the circuit if it senses voltage leaking to ground. If there is no ground wire, it will not function.
hot wires are black, white wires are ground
If this is a home wiring question and the wires are black and white then black is Hot and white is Neutral. If you also have a red wire, it is the other hot wire, and either the black or the red wire to the white one would be 120 volts, and red to black would be 240 volts.
no in resd. it's hot normally but if wired oppisate 2006 irc code
Black is hot and white is neutral.
Should be 220 to 240 V between Red and Black and 1110 to 120 V between Red and White and between Black and White.
I am guessing that your 3 wires are black (hot), white (neutral) and bare or green wire (ground). Connect black to black, white to white and ground wire to the metal case of swag kit.
The white is neutral. The house does have a neutral wire even though it may be black. One of those black wires is the neutral and the other is the hot wire. You will have to determine which is hot and which is neutral. You can easily do this with a voltage tester. The wire that lights the tester is the hot. When you wire the light simply wire the hot to hot, and the white and green to the other wire.
Your black wires are your hot wires. The white is your neutral or common. It would be best to run an equipment ground (green wire) too.
The wires for the left front window are red/black for up and green/black for white. For the right front window, the wires for up are red/white and the wires for down are green.
Assuming the wires are the correct gauge for application and breaker you use black and white wires as hot. Put red electrical tape on each end of white wire and connect red and black to the breaker output and bare wire to ground lug in panel. At receptacle connect black and red to hot contacts and bare wire to ground lug.
black wire is hot wire .And the white is the common or white is ground. Depends on what your talking about in an outlet or car battery. In a outlet the ground wire is green or bare copper. neutral is red and hot is black (I remember it by hot can kill you so black is death) if I am not mistaken. As for a car battery i think it's the opposite red is hot and black is neutral.
The new cooktop has a 4 wire connection. Red & Black are hot. White is neutral, and green is ground. You existing panel is wired with 3 wires. Black & Red are hot and green is ground. There is no neutral wire. Connect the black to black, red to red, and then connect the white and ground together at the plug.