Metal Enclosures

[al]

Is a cable tray considered a metal enclosure for grounding purposes?

250.86:
Exception No. 2: Short sections of metal enclosures or
raceways used to provide support or protection of cable
assemblies from physical damage shall not be required to
be connected to the equipment grounding conductor.

I know that cable tray is not considered a receway. Is it a metal enclosure?

 

[chris kennedy]

I wouldn't think that cable tray meets either of the following.

Enclosure. The case or housing of apparatus, or the fence or walls surrounding an installation to prevent personnel from accidentally contacting energized parts or to protect the equipment from physical damage.

FPN: See Table 110.20 for examples of enclosure types.

110.20 Enclosure Types.
Enclosures (other than surrounding fences or walls) of switchboards, panelboards, industrial control panels, motor control centers, meter sockets, and motor controllers, rated not over 600 volts nominal and intended for such locations, shall be marked with an enclosure-type number as shown in Table 110.20.

 

[Smart $]

Is a cable tray considered a metal enclosure for grounding purposes?

250.86:
Exception No. 2: Short sections of metal enclosures or
raceways used to provide support or protection of cable
assemblies from physical damage shall not be required to
be connected to the equipment grounding conductor.

I know that cable tray is not considered a receway. Is it a metal enclosure?

The exception you cite only permits it to not be connected to the EGC. I know of no relaxation from the requirement that it be grounded. Perhaps the intent is that it need not be grounded, but I just don't see the words to support such an intent.

In many cases where metallic cable tray is used, wire-type EGC's in cable and raceways are not connected to the tray anyway... the cable tray is just bonded, when not used as an EGC...

Obviously, it would be connected to the EGC if it is the EGC.