As you may or may not know, electric dryer cords in the past were connected to dryer outlets using a cord with a 3-prong plug. Two of these plugs are hot feed, totaling 240 volts of power between them, and the other being the neutral wire.
You see, the theory was that the neutral is bonded to the ground buss in your electrical panel anyway, so they are the same potential. The problem is, when you deal with wet locations and you may become a better path to ground than the neutral wire or the neutral connection becomes unattached all together. This could result in electrocution. How you ask? It's quite simple if you think about it.
Let's say the neutral wire breaks off, touches the machine case, and you then touch the machine while standing in a puddle of water. Now you become the current's path to ground and electrocution happens. You probably wouldn't know what happened because it happens so fast and so unexpectedly. If you're lucky, you'll survive the incident.
That's one reason the new cords have a 4-prong setup. There are two hot wires, a neutral wire, and a ground wire. The case of the machine is grounded directly to earth ground through its own wire and it has a separate return path, the neutral wire, for the return path of unused power to the service panel. This is a much safer electrical connection to use, so find out how to convert your 3-prong to a 4-prong electric dryer plug today.
Photo: Timothy Thiele