314.28(a)(3) clarification please.

[Gary Alzaga]

The following sentence is an excerpt from 2014 nec 214.28(a)(3)

Listed conduit bodies of dimensions less than those required in 314.28(A)(2) having a radius of the curve to the centerline not less than as indicated in Table 2, Chapter 9 for one shot and full shoe benders, shall be permitted for installations of combinations of conductors permitted by Table 1 of Chapter 9. These conduit bodies shall be marked to show they have been specifically evaluated in accordance with this provision.

Question 1. What does this listing look like on a conduit body? Is it a number or sentence or something etc?

Question 2. What is the Radius of the curve to the center line? How do you measure the "Radius of the curve to the center line"?

I know how to find the radius of a 90 degree bend in conduit. Measure from the center of one plane of the conduit up to where the conduit starts to arc in the perpendicular plane or using a math formula that uses a measurement across the radius and from the center of that measurement down to the center of the radius.

 

[Dennis Alwon]

The only markings I have notice is the number of conductors for the largest size conductor allowed.

 

[jusme123]

This section was revised to eliminate the specific conductor marking requirements for listed conduit bodies of smaller dimensions having a radius of the curve to the center line not less than as indicated in Table 2, Chapter 9. This is the same minimum radius of curve required for field bends in IMC, RMC, and EMT found in Sections 342.24, 344.24, and 358.24 respectively. Therefore, these are suitable for installations of combinations of conductors of the maximum conduit or tubing wire fill (of conduit or tubing being used) permitted by Table 1 in Chapter 9.

These designs greatly simplify wire fill calculations for conduit bodies for both design and inspection and do not require conductor size markings. The 2011 NEC® text in Section 314.28 (A) (3) was restrictive for these designs as it technically did not permit installation of the full Table 1, Chapter 9 wire fill for the conduit or tubing being used. These conduit body designs effectively negate the concern for wire jamming addressed in Informational Note No. 2 to Tables in Chapter 9.

http://tnblnx3.tnb.com/emAlbum/albums//us_resource/gm7304hr_2014NECCodeChanges.pdf

 

[Smart $]

...
Question 2. What is the Radius of the curve to the center line? How do you measure the "Radius of the curve to the center line"?
...

In simple terms, the bend radius.

 

[kwired]

In simple terms, the bend radius.

As it applies to the bend of installed conductors.

 

[don_resqcapt19]

That section is aimed at this type of conduit body. When you place the conductors the bending radius of the conductors is not less than the minimum bending radius permitted for that trade size of conduit.

 

[Gary Alzaga]

Thank you everyone for your perspectives on the subject.