Is positive the hot wire?
There's a hot wire (positive), a neutral wire, and ground. I ~assume~ that in an AC circuit, positive correlates to positive, neutral to negative, and ground to ground. Transformers will correlate the +/- when changing DC.
To prevent shocks from the metal parts of a light, lamp cords and two-wire extension cords are always polarized. This means the plug has a small blade for the hot wire and a wide blade for the neutral wire, and the wires feeding those blades should not be reversed when you put a new plug on.
- The wide prong on the plug links the threaded base of light bulbs to the neutral terminal (the wider slot) in the receptacle. If the wires are reversed, the hot side of the outlet (the side that can deliver a shock) is wired to the threaded socket.
- The protective ground is green or green with yellow stripe. The neutral is white, the hot (live or active) single phase wires are black , and red in the case of a second active. Three-phase lines are red, black, and blue.
- One side of the receptacle has (2) brass screws and the other side has (2) silver screws. The hot side of the circuit (black wire) should be wired to the brass screws while the neutral side of the circuit (white wire) should be wired to the silver screws. You only need to connect to (1) screw on either side.
The two-prong plug of unequal size and the three-prong plug are polarized. By having the two different sized prongs or a three prong design, the electrical device can only be inserted into the electrical outlet/receptacle one way.
- The left slot is called "neutral," the right slot is called "hot" and the hole below them is called "ground." The prongs on a plug fit into these slots in the outlet. If you have read How Batteries Work, you know that electricity must flow in a circuit. In a house outlet, power flows from hot to neutral.
- A common problem found in old houses is the presence of ungrounded outlets. Either you're stuck with old fashioned 2-prong outlets that won't fit your 3-prong devices, or someone replaced the old outlets with 3-pronged outlets that don't have a ground wire.
- If you cut the third prong off of a plug, you defeat the safety feature. All electrical appliances designed for outdoor and wet area use should have a third prong ground on the plug and be connected to a ground fault circuit interrupter (GFCI) receptacle.
Updated: 21st November 2019