Calculating Expansion Fittings

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jimthesparks

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Chicago, IL
When calculating expasion fittings do you have to take into account Table 310.15(b)(3)(c) in the 2011 code? It seems to me that if the temperature affects the conductors it would affect the pipe.
 

don_resqcapt19

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Illinois
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retired electrician
You have to take into account the total range of temperature from the lowest to the highest and calculate the total expansion based on that spread. The expansion joint is set based on the actual temperature at the time of the installation so the conduit can move as required as the temperature goes up or down.
 

infinity

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New Jersey
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Journeyman Electrician
When calculating expansion fittings do you have to take into account Table 310.15(b)(3)(c) in the 2011 code? It seems to me that if the temperature affects the conductors it would affect the pipe.


So you're asking if you need to factor in how much spacing is between the conduit and the roof?
 

don_resqcapt19

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Illinois
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retired electrician
The amount of expansion is based on the temperature of the conduit and not the air temperature. I think you do need to take that into account.
 
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