what is the difference between electrically grounded and electrically floating system?

Question

This is related to system electrical grounding

Answer 1

In addition to the safety aspects in tying AC powered systems to an earth ground (electrically grounded system), there are additional reasons to have a common grounding point between systems and assemblies. In many electronic applications, having metal components that are "floating" can capacitively couple electronic noise into the system. The term "floating" in this case means that the metal part(s) are not electrically tied to a reference point in a nearby circuit. It can also cause problems if two systems lying at different potentials with respect to each other are wired together for communications purposes (ie - RS232 or RS485 etc). When this occurs, the common mode specification of the components used to interface the two systems together may be exceeded resulting in damage to the components and/or faulty communications between the systems. In general, it is bad practice to leave floating metal and to not provide a common reference point (grounding point) between systems, not just for the safety aspect, but to attain reliable operation of the systems.

Answer 2

Floating Ground

Answer 3

Pretty much what it sounds like. An electrically grounded system has some point intentionally attached to an earth ground. On an AC system once the voltage is passes through a transformer it is floating. It is not referenced to the earth at any point. If it is single phase and the secondary of the transformer is, for example, 120V, then it is possible for one of the lines to be 120V to ground and one to be 240V to ground. This is a floating system. If I connect one of the legs to ground then it is at ground potential or 0V and the other will be 120V to ground. This is an electrically grounded system. Most home systems in the US have the center tap of a 240V transformer grounded. This gives 120V to ground on the two phases, the center tap is called a neutral and you have 240V between the two "hot" legs of the circuit. Panama Canal's 480V 3 phase system actually has one of its three phases intentionally grounded. Somewhat unusual but it works.

Answer 4

Electrically grounded would have mostly to do with being grounded to earth ground. That is when a wire is actually connected to the ground. A floating ground is ground that is not connected to earth ground. All circuits need a ground so how do you ground a cell phone. Well you pick the negative end of a battery. With a car you connect ground to the chassis to prevent a charge build up. The goal of a ground in all circuits is to have a reference voltage that all other voltages can be based off of.

Answer 5

It makes no difference. 99.9% of the time, we are at the same potential as 'ground' anyway. The only reason we use ESD precautions, is for the 0.1% of the time where part of us acts as a storage device of some kind, and holds a greater potential than ground. Similarly, if you were strapped to a 100,000V power line as long as you were in contact with nothing else, ever again, you'd still be fine! It's all down to voltage being relative. Your internal electrical systems all use your overall body potential as their reference, be the 100 000v above ground or exactly the same as ground. Hope that makes sense. x

Answer 6

Scott B said:

"You must bond and or ground everything to make it safe."

That is true simply because one pole of the supply is connected to earth at the generator.

In a floating system there would be no safety advantage whatsoever in connecting "everything", or indeed anything, to earth.

Answer 7

you should read up on BONDING and GROUNDING. To GROUND something is to literally have the path of least resistance to ground. Bonding is when an object is bonded to an object which may also be bonded or to which both ultimately go to ground. You must bond and or ground everything to make it safe. As for FLOATING, I am not sure....sorry, but I did find something far to lengthy to write here by typing it into Google.
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