Undersize Ground Wire

[tortuga]

Well in that case if the inspector is digging in, no help from engineer I take it, time to pinpoint the liability , fix the mistake and move on.

 

[jimport]

I thought this just came up recently and you could add the area of the conductors together.

 

[petersonra]

I think you are not compliant and no inexpensive way to become compliant.

Who decided the conductor sizing? Maybe that person can share the cost of fixing it with you. Or did you order the right size and the wrong size came in and no one noticed?

Maybe you can replace the 600 amp panel board with 4 150 amp panel boards. Would need to do something about protecting each of the four feeders then too.

 

[Tulsa Electrician]

I thought this just came up recently and you could add the area of the conductors together.

Depends on how there installed.

 

[infinity]

I think you are not compliant and no inexpensive way to become compliant.

I agree. That code section is very clear on each cable requiring a full size EGC based on the OCPD and T250.122. Without changing the cables would you be able to install a 1 to 1 Delta/Wye transformer at the end using one of the full size conductors as the EGC?

 

[Tulsa Electrician]

I thought this just came up recently and you could add the area of the conductors together.

Depends on how there installed.

This from the 2017 NEC and what you may be referring to.

"250.122 Size of Equipment Grounding Conductors.
(A) General. Copper, aluminum, or copper-clad aluminum
equipment grounding conductors of the wire type shall not be
smaller than shown in Table 250.122, but in no case shall they
be required to be larger than the circuit conductors supplying
the equipment. Where a cable tray, a raceway, or a cable armor
or sheath is used as the equipment grounding conductor, as
provided in 250.118 and 250.134(A), it shall comply with
250.4(A)(5) or (B)(4).

Equipment grounding conductors shall be permitted to be
sectioned within a multiconductor cable, provided the
combined circular mil area complies with Table 250.122."

 

[Tulsa Electrician]

I went back to the original question.
Question #1 what is the connected load for the new panel(s)

No, it did not. it came with a #4G instead of the #1G (Which I originally ordered). We are tapping the existing SWBD bus because the 600A SWBD BKR didn't have room space in the front of the switchgear. The designer in the record in turn decided to have us tap the bus, and feed into a 600A disconnect so it can provide power to a 600A/3P panel located on the 5th floor.

Question #2 Is it a single panel or two panels.
Question #3 What is the largest load and type on that panel(s)
Question #4 Is there additional space to set to 400 amp disconnects or is there space for two 400 amp frame breakers reduce to 300 amp.
Question #5 Did you discus any options with the design engineer.
Question #6 What is the Feeder voltage and Load voltages. I took it as 120/208 3- ph 4-wire ( neutral needed)
Question #7 Is there a transformer involved any where.

No, it did not. it came with a #4G instead of the #1G (Which I originally ordered). We are tapping the existing SWBD bus because the 600A SWBD BKR didn't have room space in the front of the switchgear. The designer in the record in turn decided to have us tap the bus, and feed into a 600A disconnect so it can provide power to a 600A/3P panel located on the 5th floor.

He is what I am thinking.

Install two 400 amp switch/OCD and reduce via plug/fuses to 300 amps for two feeders.
Divide load into two panels, do a load sheet.
If you have a two panels rated 600 amp no big deal. If not you would need one 400 amp main lug panel to go with the 600 if load allows.
Now you have two 300 amp feeders that the cable would code compliant for.
This may require an engineers approval or may require a AHJ approval if permit requires approved drawings
If ordered correctly sized and it was installed any way you may be able to get supply house to work with you on equipment.
Knowing it was wrong and tried to slid by then that is another story.

Other than that re pull the cables and pay closer attention before signing for wire. One reason I only sign for any wire delivered checking it against the PO and feeder schedule Before any one touches it for unload. If your deliver slip says correct cable then go back to supplier.
Either way I feel for you. Good luck

 

[petersonra]

This from the 2017 NEC and what you may be referring to.



Equipment grounding conductors shall be permitted to be
sectioned within a multiconductor cable, provided the
combined circular mil area complies with Table 250.122."

This only allows a sectioned egc within a mc cable. Not to split it between multiple cables.

 

[Tulsa Electrician]

I thought this just came up recently and you could add the area of the conductors together.

This only allows a sectioned egc within a mc cable. Not to split it between multiple cables.

Equipment grounding conductors shall be permitted to be
sectioned within a multiconductor cable, provided the
combined circular mil area complies with Table 250.122."

Depends on how there installed.

I should have said that better.
Thanks for the clarification.

 

[jimport]

What is a sectioned EGC?

 

[winnie]

What is a sectioned EGC?

Segmented EGCs are used in VFD cables where the EGC is divided into smaller wires which are distributed around the circuit conductors in a 'balanced' fashion. In other words, rather than having 1 EGC with different spacing to the 3 circuit conductors, you have 3 smaller EGC wires that are intermingled with the 3 circuit conductors so that every circuit conductor is the same distance from the EGC wires.

This page has a write-up and diagrams of the different types of VFD cable.

Quad Plus

VFDs require special cables to operate correctly without impacting nearby equipment and causing expensive downtimes for repairs. Learn more about why this happens and how to mitigate problems.

www.quadplus.com

-Jon