The difference between 4-wire 3-wire track lights

According to the principle of physics, connecting electrical apparatus is generally separated from ground wire so that lamps can be connected in series with wires. Similarly, the basic configuration of track lamps is ground wire and fire protection line. But when you buy a track lights, you will find that there are three lines and four lines of choice, so how do we distinguish it?

4-wire

The four-wire guide actually contains five wires: three fire wires, one neutral wire, one ground wire, and three fire wires respectively form a loop, and three switches can respectively control one loop, and match four gear positions on the rail lamp head, so Three lights are mounted on one rail, and different lights are turned on as needed, and different lights are on.

3-wire

The rail heads for the three-track track are three contact points, two live wires, one neutral wire, and no grounding.