20.) The supporting of cable or other raceways from raceways.
Section 300-11 (b) prohibits the supporting of other raceways, cables or nonelectric equipment from raceways. One of the most common problems found is raceways supporting other raceways.
Examples:
You have a raceway that has been properly supported to a framing member. The electrician has decided to use back to back clips to support an additional raceway directly from the first raceway.
You have electrical equipment that is located away from an interior or exterior wall or electrical equipment has been located on an interior wall does not continue all the way to the ceiling. Raceways have been run from the ceiling to the equipment or to the top of the wall. The raceways have been supported to "unistrut" or a similar product with the proper clips. However, the strut only runs across the raceways and has not been supported by any other means.
A properly supported raceway that has cable wiring methods, other than an associated class 2 circuit, secured to it. Most often cable methods are found secured to raceways with cable ties. A common example of an associated class 2 circuit would be the thermostat cable for a boiler which has been secured to the raceway which runs from the fireomatic down to the boiler.