Cable tray (expansion joints)

[Dsg319]

Is there anywhere else in the NEC book that says cable tray has to have an expansion splice plate every so many feet?

Alls I have found is 392.44 which says- Expansion splice plates for cable trays shall be provided where necessary to compensate for thermal expansion and contraction.

 

[don_resqcapt19]

NEMA has a free PDF installation guide that gives you the information needed to calculate how many expansion joints are needed.
The code never tells you that you need one every so many feet, as the distance is governed by the expansion factor of the material and the expected temperature delta.

 

[Julius Right]

NEMA Standards Publication VE 2-2013
Cable Tray Installation Guidelines
3.4.2 Expansion Splice Plates
It is important to consider thermal contraction and expansion when installing cable tray systems. The length of the straight cable tray run and the temperature differential govern the number of expansion splice plates required (see Table 3-2 and, for an example, Figure 3-38).

 

[Dsg319]

NEMA Standards Publication VE 2-2013
Cable Tray Installation Guidelines
3.4.2 Expansion Splice Plates
It is important to consider thermal contraction and expansion when installing cable tray systems. The length of the straight cable tray run and the temperature differential govern the number of expansion splice plates required (see Table 3-2 and, for an example, Figure 3-38).

Thanks all.