EMT passing through building expansion joint

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NEC User

Senior Member
The DCA inspector made a comment today that the electrical conduits passing through the building’s expansion joint require expansion couplings.
Is this required for EMT passing through the expansion joint? Per my understanding, EMT doesn’t require expansion couplings. The NEC doesn’t implicitly indicate the use of couplings as it does in other conduit type sections e.g. PVC has a sub-section titled 352.44 Expansion Fittings. Also, the coefficient of expansion for EMT conduit is not significant in areas where we don’t have sun exposure like the roof.

I'm considering telling the contractor to install a foot of flex conduit to transition across any joint.
 

jumper

Senior Member
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, contrac-
tion or deflection, used in buildings, bridges, parking ga-
rages, or other structures.
 

ADub

Senior Member
Location
Midwest
Occupation
Estimator/Project Manager
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, contrac-
tion or deflection, used in buildings, bridges, parking ga-
rages, or other structures.

Wouldn't every seam in a tip up wall structure count as a structural joint intended for expansion and contraction?


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GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
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, contrac-
tion or deflection, used in buildings, bridges, parking ga-
rages, or other structures.

I'm considering telling the contractor to install a foot of flex conduit to transition across any joint.
IMHO a foot of flex is not a listed expansion/deflection fitting, so the OP had better line up "approval" from the AHJ in advance
 

ADub

Senior Member
Location
Midwest
Occupation
Estimator/Project Manager
No clue, never worked in a building using that type of construction.

Well it's a pretty common building method, by the letter of the code you couldn't run pipe horizontally along the seams without expansion provisions every 8' which is just ridiculous


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GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
Wouldn't every seam in a tip up wall structure count as a structural joint intended for expansion and contraction?


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Is there an expansion joint in any wall finish which bridges the gap between tip up sections?
If not, I would say that any expansion which might occur is incidental and not the purpose of the joint.
 

ADub

Senior Member
Location
Midwest
Occupation
Estimator/Project Manager
Is there an expansion joint in any wall finish which bridges the gap between tip up sections?
If not, I would say that any expansion which might occur is incidental and not the purpose of the joint.

There is about a 3/4 gap between sections that is filled with backer rod and then caulked. I know for a fact these wall sections move slightly but we don't consider it when install conduits because its inconsequential


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kwired

Electron manager
Location
NE Nebraska
The DCA inspector made a comment today that the electrical conduits passing through the building’s expansion joint require expansion couplings.
Is this required for EMT passing through the expansion joint? Per my understanding, EMT doesn’t require expansion couplings. The NEC doesn’t implicitly indicate the use of couplings as it does in other conduit type sections e.g. PVC has a sub-section titled 352.44 Expansion Fittings. Also, the coefficient of expansion for EMT conduit is not significant in areas where we don’t have sun exposure like the roof.

I'm considering telling the contractor to install a foot of flex conduit to transition across any joint.

The PVC issue is to protect the PVC itself from it's own thermal expansion/contraction.

A building/structure expansion joint is put in place because they expect expansion/contraction of the building, and that joint is where they are allowing for movement. If you bridge across that joint with something that can't move with each side of the building it will strain the object you are bridging it with when the separate building parts do move.
 

Fulthrotl

~Autocorrect is My Worst Enema.~
The DCA inspector made a comment today that the electrical conduits passing through the building’s expansion joint require expansion couplings.
Is this required for EMT passing through the expansion joint? Per my understanding, EMT doesn’t require expansion couplings. The NEC doesn’t implicitly indicate the use of couplings as it does in other conduit type sections e.g. PVC has a sub-section titled 352.44 Expansion Fittings. Also, the coefficient of expansion for EMT conduit is not significant in areas where we don’t have sun exposure like the roof.

I'm considering telling the contractor to install a foot of flex conduit to transition across any joint.

if it's a designed expansion or movement area in a structure, then any non flexible raceway would require
expansion joints where it crosses.

http://www.cooperindustries.com/con...-emt_series_conduitexpansionjointsforemt.html

cooper makes them.

[h=1]XJG EMT Series Conduit Expansion Joints for EMT[/h]
 
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