NEC 300.7B Clarification

[jbeasley]

Currently installing 3/4 EMT on a fed govt. project. We are being advised by the govt. expansion couplings are needed at each expansion joint in the building. All areas EMT is being installed is air conditioned space. 300>7B states to install to compensate for thermal expansion and contection
Are expansion couplings required in this application

 

[rbalex]

You jumped over the relevant Section. See Section 300.4(H).

 

[JFletcher]

You jumped over the relevant Section. See Section 300.4(H).

What section is that in the 2008 NEC? there is no 300.4 H in the 08.

 

[tw1156]

What section is that in the 2008 NEC? there is no 300.4 H in the 08.

300.4 (Protection against physical damage)

300.4(H) - Structural Joints. A listed expansion/deflection fitting or other approved means shall be used where a raceway crosses a structural joint intended for expansion, contraction or deflection, used in buildings, bridges, parking garages, or other structure.


I don't have the '08 NEC, but posted the verbiage so maybe you can locate the section

 

[rbalex]

What section is that in the 2008 NEC? there is no 300.4 H in the 08.

It was introduced in the 2011 Code and has been there ever since.

 

[JFletcher]

Thank you gentlemen. I knew of the rule, now I know why I cannot find it in the 08 book. I thought the requirement had been around longer that

 

[kwired]

Currently installing 3/4 EMT on a fed govt. project. We are being advised by the govt. expansion couplings are needed at each expansion joint in the building. All areas EMT is being installed is air conditioned space. 300>7B states to install to compensate for thermal expansion and contection
Are expansion couplings required in this application

300.4 (Protection against physical damage)

300.4(H) - Structural Joints. A listed expansion/deflection fitting or other approved means shall be used where a raceway crosses a structural joint intended for expansion, contraction or deflection, used in buildings, bridges, parking garages, or other structure.


I don't have the '08 NEC, but posted the verbiage so maybe you can locate the section

If your specifications are to use an expansion fitting - that may be what you are stuck with using, otherwise per code other approved means are acceptable - like a short section of flex. Along with that method may come additional bonding requirements because of the flex, but may be an issue with an expansion fitting also - I've never used any other then on PVC raceways, but can see potential bonding issues across them.