I don’t know much about how plugs or electricity works, obviously, but I was taught that one side is the “positive”, one side is the “negative”, and the bottom (seemingly quite optional) is the “ground”. It’s odd to me that so few plugs use the “ground”, so it made me curious why it exists, and why it’s optional. Are there any safety benefits to having a “ground”, or safety concerns with not having one? Thank you!
In: Engineering
Two prong outlets were installed in ungrounded systems-no actual connection to ground on the property at all.
Three prong outlets were installed in grounded systems-the neutral is physically connected to the earth at one single point at the main disconnect.
The grounded system is safer because it bonds all metal in the system together and it also bonds w metal pipes in homes and with metal cases on equipment that plugs in.
If a voltage is accidentally placed on a metal pipe (for example) in an ungrounded system, the voltage stays there until it is removed or it may even push a current through your body if you touch that metal pipe.
If a voltage is accidentally placed on a metal pipe in a grounded system, a current will immediately flow through that metal pipe and everything bonded to it back to the main service. Since the impedance is purposely very low through all these bonded metals, the current will quickly grow large. The circuit breaker for this branch circuit will then trip very quickly because this current demand is large. In a properly bonded system, this would happen very quickly and the risk of shock and fire goes down tremendously.
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