Any Idea Why TC Integral Grounds Seem Undersized?

[That Man]

Running 350KCMIL TC, and the NEC states that the ground wire for for a 350 should be 1/0AWG, but the Houston 154 TC spec lists an integral ground wire sized at 3AWG. This makes it seem like I have to run an extra ground conductor, which luckily is 1/0 and so it also TC rated. But if I needed to run say, a 250KCMIL, I'd still have to run a 1/0 ground. What's the point of the integral ground if it's too small? What am I missing?

 

[winnie]

Running 350KCMIL TC, and the NEC states that the ground wire for for a 350 should be 1/0AWG,

How do you determine that you need 1/0 AWG ?

If I look at the 90C rating of a 350 KCMIL Cu conductor, table 310.16 gives 350A.

If I have a circuit protected by a 350A OCPD, table 250.122 requires a 3 AWG EGC.

But I can see a different set of assumptions or different conditions leading to a larger EGC requirement.

 

[don_resqcapt19]

and the NEC states that the ground wire for for a 350 should be 1/0AWG,

Where does it say that? Are you looking at the requirements for a grounding electrode conductor or an equipment grounding conductor?
The product standard for TC requires a 3AWG for tray cable with ungrounded conductors 300 through 400kcmil (copper)

 

[That Man]

Where does it say that? Are you looking at the requirements for a grounding electrode conductor or an equipment grounding conductor?
The product standard for TC requires a 3AWG for tray cable with ungrounded conductors 300 through 400kcmil (copper)

It says it on the chart! ...the wrong chart (250.102(C)(1)).

Thank you. I figured I was doing something wrong. What a relief.