Corner Grounded Delta

[poweringtech]

In a corner grounded delta. Is it true that theoretically the line which is grounded is safe to touch because it is at zero potential to ground even if there is a current flowing through it? :roll:

How safe is it?

Have a great day to all

 

[petersonra]

Re: Corner Grounded Delta

There would be no or very low voltage between the phase and ground. That does not mean it would be safe to touch it while it is live.

Getting close enough to touch it would presumably involve opening up an electrical cabinet that had wires that have a much higher potential to ground on them. There is inherent danger in exposing yourself to such a hazard.

 

[don_resqcapt19]

Re: Corner Grounded Delta

As with all grounded conductors, there will be a voltage to earth at any point on the load side of the main bonding jumper. This is the voltage drop caused by the current flow in the grounded conductor.
Don

 

[LarryFine]

Re: Corner Grounded Delta

To relate this question to more familiar circumstances, it would be the same as a neutral in 1- or 3-phase wiring systems. It's grounded at the service, but should be treated as a current-carrying conductor beyond.

 

[charlie b]

Re: Corner Grounded Delta

But I wouldn't touch it, even at the service. Why not. Well if you haven't seen it, go to the Safety Topic Area, and check out the thread called "Non Sequitur."

 

[procs]

Re: Corner Grounded Delta

The grounded line of the corner-grounded delta is safe to touch with or without load at the end of the line only when the line is properly bonded to ground. The line is also safe to touch even when it is not properly bonded only when the load is shut off. It is very dangerous to touch the grounded line in a corner-grounded delta when the line is accidentally open or loose especially when there is a load connected to it. The Human body will serve as the return path for the current, electric shock or electrocution may result. If you are not sure of the condition of the line, "NEVER TOUCH THE LINE".

 

[don_resqcapt19]

Re: Corner Grounded Delta

Electrical conductors are never safe to touch unless you have placed them in a de-energized condition and locked out the source of power.

 

[bthielen]

Re: Corner Grounded Delta

Doesn't this support the clarification we need between grounding and bonding? Unless I am bonded to another object, there is a possibility of voltage potential difference between myself and the object. A conductor being grounded only implies that it is connected to earth but does not mean it is necessarily at the same potential as I am. Even two points on earth can show potential difference, correct?

Bob

 

[George Stolz]

Re: Corner Grounded Delta

Originally posted by bthielen:
Doesn't this support the clarification we need between grounding and bonding?

How so? What aspect makes you say that?

Even two points on earth can show potential difference, correct?

True. Ground rods have a 6' sphere of influence, which would mean the voltage at the rod could be very different than the earth 3', 6', or 9' away from the rod.

 

[charlie b]

Re: Corner Grounded Delta

Originally posted by bthielen:Even two points on earth can show potential difference, correct?

To add to George's statement, consider the phrase "step potential." It refers to the possibility that there is a voltage gradient along the dirt road that you are walking upon. The distance between your steps is likely to be under 3 feet. Under severe conditions (e.g., downed power line), and even at that short distance, the potential difference between your left foot and your right foot could be enough to give you a fatal shock.

 

[bthielen]

Re: Corner Grounded Delta

The question of whether it would be safe to touch the grounded conductor raises some concern for me. I believe this may be true if and only if the person is bonded to the same ground reference as the conductor. If I am not somehow bonded to the same potential as the grounded conductor, it stands to reason that it is NOT safe for me to touch it because there is a potential for a voltage difference between myself and the grounded conductor.

With that said, it is never safe to assume you're safe. As Charlie pointed out, even a couple feet can make a difference. (pun intended)

If I'm wrong, I look forward to an education from you more seasoned, knowledgeable folks.

Bob

 

[Dnkldorf]

Re: Corner Grounded Delta

You could look at it like this:

If you decide to touch it and your wrong, you only made that mistake once, only once....

Is it worth it?


Dnk......