Safety Grounds on 4 wire circuit

[farmaped]

When applying safety grounds on a 4-wire circuit, would the neutral wire need connected?
This came about one day, the (my) method is connecting the three phases together/to ground. I was asked, why aren't you connecting a safety ground to the neutral ... my response was, well, the neutral IS grounded, somewhere.
What do others do, other see, and what would be the correct answer?
Thanks!

 

[RichB]

Are you sure? To me the first word in the tittle says it all--besides how long does it take to attach to the nuetral also?

 

[SG-1]

250.24(A)(5) prohibits the grounding of the grounded circuit conductor (neutral) at any point beyond the service. There are 3 exception listed: 250.30, 250.32, & 250.142 in the Fine Print Note.

 

[SG-1]

Please watch this: http://www.tirebiter.net/downloads/ludecke.html

The link was taken from the Grounding vs Bonding Forum. It would do you good to open that Forums first post & read: Grounding vs Bonding The Big Picture Post.

The correct method is to use an EGC to bond the metal parts together to create an effective ground-fault current path. During normal operation the grounded conductor ( neutral ) carries current. If you bond the grounded conductor to the equipment frame the neutral current will then be on the frame. This creates an undesirable & possibly dangerous condition.

Except under a few conditions driving ground rods beyond the service does little or nothing to enhance safety.

 

[farmaped]

Thanks for the feedback. To clarify safety grounds, these are temporary grounds applied (attached/connected) on de-energized circuits, rated for the available SC current, bonding all three phases (of a 3-phase sytem) & ground. While I agree the time to connect the neutral is minimal, and certainly touching the neutral with a ground stick to discharge any induced or static charge would take even less time (and personally done every time), is connecting the neutral necessary? I say this under the assumption 250.24(A)(5) would not apply, but I have been wrong before. Since the OP I have checked 70E, which says "phase conductors", slightly adding to my confusion.

 

[Hv&Lv]

Thanks for the feedback. To clarify safety grounds, these are temporary grounds applied (attached/connected) on de-energized circuits, rated for the available SC current, bonding all three phases (of a 3-phase sytem) & ground. While I agree the time to connect the neutral is minimal, and certainly touching the neutral with a ground stick to discharge any induced or static charge would take even less time (and personally done every time), is connecting the neutral necessary? I say this under the assumption 250.24(A)(5) would not apply, but I have been wrong before. Since the OP I have checked 70E, which says "phase conductors", slightly adding to my confusion.

I install safety grounds to all three phases and the neutral. (POCO) The neutral in your circumstance may be grounded somewhere, but where? Is it still intact? Is it grounded before the switch? We ground to the neutral because our reclosers monitor neutral amps also.
What does 70E tell you? (I don't have one)

Will this ground you are connected to carry the induced current and anticipated fault current that could flow at the point of grounding for the time necessary to clear the line?

 

[SG-1]

I believe that everyone would be safer if the neutral were grounded also.

Here is why:

If there is a problem ( high resistance connection or open ) with the neutral conductor it will manifest itself & get corrected.
If the same problem exists with the EGC or ground it will not be detected until after a ground fault. One loose conduit fitting could compromise the entire low impedance ground fault path that you & your co-workers are depending on for your personal safety.

The grounded conductor ( neutral conductor ) is the larger conductor & therefore should be the lower impedance path.

 

[farmaped]

I install safety grounds to all three phases and the neutral. (POCO) The neutral in your circumstance may be grounded somewhere, but where?

Is it still intact?

Is it grounded before the switch?

These are all great points. The more I think about it, the more I think it should be done.

What does 70E tell you? (I don't have one)

Where possibility of induced voltages or stored electrical energy exists, ground the phase conductors or circuit parts before touching them. Where it could be reasonably anticipated that the conductors or circuit parts being de-energized could contact other exposed energized conductors or circuit parts, apply ground connecting devices rated for the available fault duty.

Will this ground you are connected to carry the induced current and anticipated fault current that could flow at the point of grounding for the time necessary to clear the line?

Indeed

 

[jimmac49]

Thanks for the feedback. To clarify safety grounds, these are temporary grounds applied (attached/connected) on de-energized circuits, rated for the available SC current, bonding all three phases (of a 3-phase sytem) & ground. While I agree the time to connect the neutral is minimal, and certainly touching the neutral with a ground stick to discharge any induced or static charge would take even less time (and personally done every time), is connecting the neutral necessary? I say this under the assumption 250.24(A)(5) would not apply, but I have been wrong before. Since the OP I have checked 70E, which says "phase conductors", slightly adding to my confusion.

Have a look at the NESC. Not sure what type of system you are working on but the NESC adresses saftey rules and grounding in both overhead and under ground systems.

Jim Mc

 

[Strife]

It is, for the longest time the term "neutral" didn't even exist in the NEC. it was the "GROUNDED CONDUCTOR". It's only the last 3-4 cycles that NEC started using the term neutral.
Grounded being the keyword?
However I could see the issue in a NON SOLID neutral situation.

When applying safety grounds on a 4-wire circuit, would the neutral wire need connected?
This came about one day, the (my) method is connecting the three phases together/to ground. I was asked, why aren't you connecting a safety ground to the neutral ... my response was, well, the neutral IS grounded, somewhere.
What do others do, other see, and what would be the correct answer?
Thanks!

 

[K8MHZ]

Since the energy is looking for a way back to the source, which would be via the neutral, not the ground, wouldn't it be prudent to safety ground it? If I was going to leave one out, I would leave out the grounding conductor, not the neutral, but to be sure of safety, all conductors should be bonded and grounded.

The linesmen around here have a saying. " It ain't dead if it ain't grounded"