NEMA 4 – NEMA STANDARD CABLE TRAY & LADDER

Exstract from Nema Supports Publication 

 Horizontal Wye Supports

Within 2-feet (610mm) of each of three openings connected to the other cable tray items at 22 1/2 degree point of arc adjacent to the side branch

Reducer Supports

Within 2-feet(610mm) of each fitting exstremity

6.6.3 Vertical Cable Tray Elbow

Vertical cable tray elbow at the top of runs should be supported at each end.Vertical cable tray elbow at the bottom of the runs should be supported at the top of the elbow and within 2- feet (610) of the lower exstremity of the elbow.

6.6.4 Vertical Cable Tray Tees

Vertical cable tray tees should be supported within 2-feet (610mm) of each fitting exstremity.

6.6.5 Vertical Straight Sections

Vertical straight sections should be supported indoors at appropiate intervals permitted by the buiding structure:outdoor support intervals should be determined by wind loading.The maximum distance between vertical supports should not exceed 24feet (7320) on centres

6.6.6 Sloping trays 

Sloping trays should be supported at intervals not exceeded those for horizontal trays of the same design for the sump installation

6.6.7 Fitting as End of Run 

A fitting which is used at the end of a run dropout should have a support attached to it ,firmly reinforcing the fitting.

6.7 Protection of Cable Insulation

The inside of cable tray systems should presnt no sharp edges,burrs, or projections which could damage cable insulation.