Equipment Grounding Conductor - Distribution

[Dodge2382]

Hi,

I am routing conductors from one set of 5KV switchgear to feed another set of 5KV switchgear across a plant. Is it necessary for me to run an EGC (equipment grounding conductor) with my phase conductors?

If so, what about if 75% of the run is on overhead pole line? How do I run the EGC?

Thanks.

-Derek

 

[don_resqcapt19]

I don't see any thing in Part X of Article 250 that says you don't need an EGC with the exception of a multigrounded neutral system.
As far as how you install it on an overhead line, if the cable being used is messenger supported, the messenger is often the EGC. If not, you have to install an additional conductor.

 

[charlie b]

I agree with Don. Furthermore, other than any cost considerations, I can't think of a reason not to run an EGC.

Welcome to the forum.

 

[Dodge2382]

Thanks for the responses.

What exactly is a "Multigrounded Neutral System"?

This system has a 15MVA Delta-Wye XFMR with a 400A neutral ground resistor. This transformer feeds the first line-up of 5kV swgr in Sub 1 and then Sub 1 feeds another line-up of 5kV swgr 700 ft away in Sub 2.

I am concerned with the feed from Sub 1 to Sub 2, which will be ran in both tray (25%) and on pole line (75%).

Thanks.

 

[don_resqcapt19]

...
What exactly is a "Multigrounded Neutral System"?...

It is a system where the grounded conductor it bonded to earth at multiple locations. The utilities very often use this type of distribution.
You have a grounding resistor so you can't have a multigrounded neutral system. What type of cable or conductors are you planning on using for the overhead?

 

[Dodge2382]

I am connecting to existing overhead. They are paralleled 500KCMIL bare wire. These will make up 75% of the run between Sub 1 and Sub 2 5kV swgr.

If I have a low resistance grounded neutral system (400A). Don't I run an equipment ground conductor from the ground side of the resistor at the 15 MVA transformer to the switchgear in Sub 1, along with the phase conductors? Once there don't I terminate on the switchgear ground bus.

Thanks.

 

[mbrooke]

I would run an EGC. Utilities usually dont when all loads are connected phase to phase but have other measures in place to detect faults. In your case one will serve you well.

Run the egc a few feet below the phases if you had to pick.