Any circuit's black wire should be considered hot or live. Black wire is never used for a ground or neutral wire and should be used as the power feed for a switch or an outlet. A black wire is often used in a circuit as a switch leg, the connection that runs from the switch to the electrical load.
Black-sheathed cable is used for both 6- and 8-gauge wire. 8-gauge wire is rated for 45-amp circuits, while 6-gauge wire is capable of handling 60-amp circuits. The 6-gauge wire is better for a feeding a sub panel, an electric range, or a double oven, depending on the amperage rating listed on the appliance.
If you need black cable, make sure to read the sheathing and packaging carefully to determine if you are buying 6-or 8-gauge wire.
Not necessary, it depends on the application where the cable is required. Some fire resistant cables have red outet jackets that is fire resistant materials. Probably also the LSOH" low smoke zero halogen " cables are red outer jackets. The XLPE and regular PVC cables are black
Because it is made up of vinyle plastic which streaches well and gives a long lasting insulation . Due to this also electrical tapes are also commonly in black colour
There are cables with different colors, for example, red, orange, grey.
PVC or HDPE, the plastics that the jacket of the cable is made of, have to be UV-stabilized. Carbon black is a common and cheapest additive for it purpose