wet locations

[Golfnut1]

I was just wandering, in the 2011 NEC ,Article 300.5b states that the interior of any raceway or enclosure installed underground shall be considered as wet locations and the conductors installed in these raceways or enclosures shall be listed for use in wet locations. Then in Article 300.9 it states that where raceways are installed in wet locations above grade, the interior of these raceways shall be considered to be a wet location. My question is, if the interior of a raceway is considered a wet location underground and above ground in wet locations and the conductors installed in these raceways shall be listed for use in wet locations, then why isn't the interior of an enclosure above ground in wet locations considered a wet location and the conductors installed in these enclosures be made to be listed for wet locations. If it is in the code somewhere, I cannot find it.​

 

[Dennis Alwon]

Well the code does not consider the inside of the enclosures as wet location. If that were true every exterior panel box would need circuit breakers rated for wet location.

 

[Golfnut1]

wet locations

Well the code does not consider the inside of the enclosures as wet location. If that were true every exterior panel box would need circuit breakers rated for wet location.

I know. Also it would require the conductors to be listed also. Which would mean you couldn't install nm cable in nema 3R type outdoor panel enclosures, outlet boxes, splice boxes,etc. It would have to be changed to a different conductor before entering these outdoor type enclosures. That brings another question into the cenario. The 2011 NEC Article 225.22 states that raceways on the exterior of buildings or other structures shall be arranged to drain and shall be suitable for use in wet locations. Where do these raceways drain to? They would drain to these enclosures wouldn't they. Something to think about. I know some brands of the enclosures are listed for wet location use, but they do not have drain holes in them. Again, something to think about.

 

[Dennis Alwon]

We all know the NEC is not fool proof. Trying to determine what the intent is can be a task in and of itself. I would also bet that nm cable in a conduit on the exterior of a building would last our lifetime. I have seen it underground for 25+ years with no ill affect.

 

[JDB3]

At a marina (back in the 70's) in Austin, Texas I saw romex (NM) going from spider docks to spider docks. Just draped in the water from one to the other (I believe that was a wet location use).

 

[david]

Where do these raceways drain to? They would drain to these enclosures wouldn't they. Something to think about. I know some brands of the enclosures are listed for wet location use, but they do not have drain holes in them. Again, something to think about.

when you arrange your conduits to drain provide weep holes to drain before the enclsures you would want to prevent codisation from entering into

 

[kwired]

Although the inside of enclosures is not considered a wet location it is a good idea to take care when entering the enclosure with raceways. Even if moisture does not enter the raceways from outside it does form inside from condensation. This moisture will drain through the raceway until finding a low point, and will start to accumulate there. NEMA 3 R enclosures will have drain holes. NEMA 12 will not. Unless NEMA 12 rating is absolutely needed for some reason drilling weep holes gets rid of the water in an enclosure. You also need to be aware of how you enter an enclosure containing circuit breakers, motor starters, or other equipment that may not be desirable to have this water dripping on or following conductors to these types of components. Making drip loops, they don't have to be much, just lower than the termination, will make that water drip there instead of following the conductor to its termination.

Load centers with a top feed main breaker and conductors entering the top center of the enclosure are not all that good of an idea, yet many of us make this install frequently. Any moisture within the supply raceway follows conductors right to the terminals and then into the main breaker. Something to think about next time you do an install like that.

 

[cripple]

wet locations

We all know and understand outdoor panelboard and switchboard enclosures are provided with same means of drainage (weep holes). The main thing to consider about this issue is the die cast boxes (FS or Bell boxes) which do not have any provision for drainage, which is required by the last sentence in section 11.5.2 of UL standard 514A. If this type of enclosure is not provided with the provision for draining, how could you not call the interior a wet location?
UL 514A
?6.4 Wet location boxes
6.4.1 All parts required to comply with the applicable requirements in Clause 12.20 shall be provided with installation and assembly instructions.?

?11.5.2 A bushed hole for open wiring shall not be located in the top or back of a box unless a hood is provided. When a hole is located in a side or under a hood, the hole and the hood shall be formed to direct a wire leaving the enclosure downward. There shall be a provision for drainage in a box containing a knockout, an unthreaded hole, or a hole bushed for open wiring.?