What will the voltage be?

[electrofelon]

The reason for my, as to why we ground the electrical system. If I understand it correctly, If the system is not grounded the voltage could be any value, even though capacitive, there is a chance of getting shocked. Now, if the system is grounded the voltage value is stable at 120V and for sure one will get shocked and possibly killed.

Then why do we ground the system? what value does a grounded system offer vs a non grounded system.

They are just different electrical system topologies, and there are advantages and disadvantages to each. Basically whether a system is grounded or ungrounded determines the insulation levels of components, which system conductors get OCPD's, and how faults Are handled.

Advantages of grounded systems:
1. Automatic operation for first faults. Monitoring or knowledgeable people not required (this is probably the biggest one)
2. Solid ground reference holds voltage between components to known and stable levels, thus some circuit components can have less insulation or even be bare.
3. Typically one circuit conductor (the grounded one) does not need an OCPD.
4. Overall, just generally easier to troubleshoot test and work on because of solidly defined voltage between all components and ground.


Disadvantages of grounded systems:
1. Stray current issues
2. High and dangerous fault current levels for first faults.

Advantages of ungrounded systems:
1. Operation can continue after first fault, it just becomes grounded system.
2. No high current faults with high incident energy for first faults.
3. Less stray current issues.

Disadvantages of ungrounded systems:
1. Typically requires knowledgeable individuals and intervention after first faults.
2. Arcing type faults can result in higher than system voltage on components stressing or damaging insulation. Because of this, insulation ratings typically need to be higher than system voltage.

 

[Ponchik]

@ electronfelon

1. Automatic operation for first faults. Monitoring or knowledgeable people not required (this is probably the biggest one)

The OCPD at the service will trip if there is a ground fault down stream from the main disconnect regardless if the utility's transformer has a GEC

 

[Ponchik]

Your body becomes the bonding jumper, not totally different than a high impedance ground. Don't be doing this when another fault occurs.

Whether the utility transformer GEC is present or not, I will get shocked with the 2nd fault.

 

[electrofelon]

@ electronfelon

The OCPD at the service will trip if there is a ground fault down stream from the main disconnect regardless if the utility's transformer has a GEC

If it's an ungrounded system, then no the breaker will not trip on a first ground fault.

I don't really know what you mean by "utilities transformer has a gec", but if I had to interpret that I would say if it has a gec then it is a grounded system