what is the difference between a grounded and ungrounded system?

Answer 1

I'm not sure if what you worded is what you really wanted. Nobody answered correctly the way you worded it ("system"). This might be more detail than you want, but more correct.

Many other answers mentioned the 3rd prong on your outlets, unfortunately called the ground pin. In a grounded system, it is grounded, but it is still present in an ungrounded system. It serves different purposes in grounded and ungrounded systems. Different countries also treat grounding differently, which can add to the confusion. It is related to safety of course, and most people really don't understand what is going on, even many electricians. The code has rules to follow, not the explanations on why those rules are there.

Most electrical systems in the US are grounded. This means one of the circuit conductors (called the grounded conductor in the code) is connected to ground at the service. For homes, this conductor is the neutral, but in some 3-phase systems without a neutral, one of the phase conductors is grounded. The other circuit conductors are ungrounded. This solid conductor to ground is why you can get a shock between the "hot" conductor and the earth, water, etc. There are countries that do not do this because they feel it is unsafe. However, this grounding of the system keeps the voltages stable.

Now, an ungrounded system, where allowed by the national electrical code, will NOT ground the neutral or other conductor. The "ground pin" on your outlet is connected to earth in this case. There is no shock hazard from touching any one conductor (same concept as an isolation transformer). When these systems are used, ground fault detectors are needed to detect a ground fault. The reason these systems are used, is so a ground fault does NOT shut off power. In a grounded system, a ground fault (connection of a hot circuit conductor to ground) will trip a circuit breaker.

There is also something called impedance grounding, which is connecting a neutral or other conductor to ground through a high impedance. This is sort of a compromise between the two.

The grounded system is the most common in the US, and required in many instances (all single phase services you'd find in your house must be grounded). With this system, the "ground pin" on your outlets is connected to the equipment grounding conductor, which is connected to the neutral (grounded conductor) at the service. This causes a high current on a ground fault to trip the circuit breaker. A ground on an outlet should never be connected to the earth, as that will not function. It should also be connected to the neutral ONLY at the service, otherwise you can energize exposed metal parts and create a hazard.

Grounding is complicated, and if it isn't done right can be dangerous. It is why licensed electricians should do electrical work.

Answer 2

Grounded Vs Ungrounded

Answer 3

An ungrounded system has only two wires to conduct electricity between the power system and the load (appliance, light, tool, etc.) One of the wires is 'hot' with 110 volts, while the other is the neutral return wire. The hot wire is black while the neutral is white.

Even though the neutral wire is connected to ground back at your house's circuit breaker load panel, if the neutral path became broken or open somewhere, then *you* as the appliance user could be electrocuted if you contacted the hot wire with one hand and you had another hand or foot with a low resistance path (your hand was wet) touching a ground path, such as a water pipe.

For that reason, most new power tools and appliances are double-insulated to give you 2 layers of protection in the event of an internal open or short circuit. The internal wires are insulated and the tool's casing is made from plastic. A break on either the hot or neutral would not conduct power to the user.


A grounded system has an extra safety path contained in its wiring - a third bare copper wire is provided in the house's wiring system and tied to ground. Inside an appliance or tool, a third insulated wire is tightly screwed to the appliance's chassis or casing. If the hot or neutral wires were to break, then the third wire would protect from an accidental short circuit by providing a direct path to ground, and the user would not be electrocuted.

Hope this helps.

Answer 4

Ungrounded Conductor

Answer 5

This Site Might Help You.

RE:
what is the difference between a grounded and ungrounded system?

Answer 6

Grounded electrification system is one of the third pin of the plugging is making a contact with a copper wire which has a connection to ground either through your water pipe or directly into a ground.Ungrounded mean your third pin is not connected simply polar or bipolar system..Most of the equipments needed to be plugged into a grounded plug in.Otherwise some time during thunderstorm or heavy rainfall your appliances will get shot circuits of electrical arch which happened in the sky.

Answer 7

Every appliance and most home entertainment equipment have a third plug when you plug it into the wall, thats the "Ground" line whic does exactly that, sends power to the ground by way of your pipes. This prevents electricutian to you when you touch something that isnt wired properly.

Answer 8

It is meant to protect you for being electrocuted. Also, if you have a storm, it will prevent the electrical current from entering the live wires in your house. Most new plugs are designed for this. You can tell because they have three plugs instead of two.

Answer 9

Tom SJ must be a electrician -- or close to it. Go with his answer to your question-- I don"t see how anyone can improve upon his answer. He has my vote.