Use of watertight hubs

[elecsayles001]

I recently joined a crew that had installed 1" rigid on a roof. The conduit is horizontally terminated into a 12 x 12 Nema3R J box with no raintight hubs. Now the J box is covered from the elements and there are no live parts inside. It is just a feed through box wit #10 and #12 wire. The engineer is rejecting this work. Is there a NEC code reference that states raintight hubs will be installed? The only code reference's I found are 225.22 and 300.9.

 

[jumper]

The only thing I can find at the moment is 314.15(A).

 

[Smart $]

I recently joined a crew that had installed 1" rigid on a roof. The conduit is horizontally terminated into a 12 x 12 Nema3R J box with no raintight hubs. Now the J box is covered from the elements and there are no live parts inside. It is just a feed through box wit #10 and #12 wire. The engineer is rejecting this work. Is there a NEC code reference that states raintight hubs will be installed? The only code reference's I found are 225.22 and 300.9.

There is no NEC requirement to install "raintight hubs"... because there are other means to make a "raintight" connection, such as sealing locknuts and/or washers. And though there are several references throughout the code regarding installations in wet locations, the main one regarding boxes and [raceway] fittings is 314.15.

314.15 Damp or Wet Locations. In damp or wet locations, boxes, conduit bodies, and fittings shall be placed or equipped so as to prevent moisture from entering or accumulating within the box, conduit body, or fitting. Boxes, conduit bodies, and fittings installed in wet locations shall be listed for use in wet locations.

Interpretation of Code could consider 314.15 as superceding 312.2, which is where it says, "For enclosures in wet locations, raceways or cables entering above the level of uninsulated live parts shall use fittings listed for wet locations." Under 314.15 one has to use wet location fittings below, too. If you think about it, 312.2 doesn't say you don't have to use wet fittings below the required level, it just says you must above...

 

[infinity]

There is no NEC requirement to install "raintight hubs"... because there are other means to make a "raintight" connection, such as sealing locknuts and/or washers. And though there are several references throughout the code regarding installations in wet locations, the main one regarding boxes and [raceway] fittings is 314.15.

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Interpretation of Code could consider 314.15 as superceding 312.2, which is where it says, "For enclosures in wet locations, raceways or cables entering above the level of uninsulated live parts shall use fittings listed for wet locations." Under 314.15 one has to use wet location fittings below, too. If you think about it, 312.2 doesn't say you don't have to use wet fittings below the required level, it just says you must above...

I don't see how 312.2 would have anything to do with a junction box as mentioned in the OP. That article is for cabinets, cutout boxes and meter socket enclosures.

ARTICLE 312 Cabinets, Cutout Boxes, and Meter Socket Enclosures
312.1 Scope.
This article covers the installation and construction specifications of cabinets, cutout boxes, and meter socket enclosures.

A junction box would need to meet 314.15 as Smart has suggested.

 

[mpd]

The engineer is rejecting this work.

did the engineer spec raintight hubs in his/her design?

 

[Cow]

Why would you need raintight hubs in this application? The manufacturers put drain holes in 3R boxes for a reason. They aren't watertight, they're only raintight. The little bit that slips by the conduit through the KO into the box will simply drain out. What's the big deal?

Did the engineer check to make sure they used rubber washers under the screw heads where they secured the box to the wall? Otherwise water could enter the box there too.:roll:

 

[mpd]

Why would you need raintight hubs in this application? The manufacturers put drain holes in 3R boxes for a reason. They aren't watertight, they're only raintight. The little bit that slips by the conduit through the KO into the box will simply drain out. What's the big deal?

Did the engineer check to make sure they used rubber washers under the screw heads where they secured the box to the wall? Otherwise water could enter the box there too.:roll:

only the engineer could answer that those questions, but i agree with you

 

[Smart $]

I don't see how 312.2 would have anything to do with a junction box as mentioned in the OP. That article is for cabinets, cutout boxes and meter socket enclosures.

OP'er implied such when he/she mentioned live parts had some beaing on the matter. AFAIK, 312.2 is the only wet/damp location requirement which has a live part clause.

 

[Smart $]

Why would you need raintight hubs in this application? The manufacturers put drain holes in 3R boxes for a reason. They aren't watertight, they're only raintight. The little bit that slips by the conduit through the KO into the box will simply drain out. What's the big deal?

Did the engineer check to make sure they used rubber washers under the screw heads where they secured the box to the wall? Otherwise water could enter the box there too.:roll:

Perhaps because the Code says so

I agree it is no big deal... until you don't comply and get called on it !!!

 

[danger30]

I have debated this issue in the past and have come to the conclusion that you always have to use sealed fittings in nema 3R pull boxes unless you terminate in the bottom. Have you ever seen a factory knockout in a 3R box anywhere but the bottom?

 

[fishin' electrician]

Have you ever seen a factory knockout in a 3R box anywhere but the bottom?

Yup - every 3R A/C disconnect I've ever installed has side KO entries.

 

[readydave8]

Yup - every 3R A/C disconnect I've ever installed has side KO entries.

low in the side below lugs

 

[danger30]

that would be covered in article 312 not 314.

 

[Smart $]

I have debated this issue in the past and have come to the conclusion that you always have to use sealed fittings in nema 3R pull boxes unless you terminate in the bottom. Have you ever seen a factory knockout in a 3R box anywhere but the bottom?

Yup - every 3R A/C disconnect I've ever installed has side KO entries.

low in the side below lugs

This is where 312.2 comes into play... but as I mentioned earlier, 314.15 supercedes it. As such and regardless of KO location, fittings are required to be wet-location listed where fittings are used in wet locations. Also note4 that many consider the bottom of a 3R or more weatherproof box/enclosure to be a damp location, such that wet location fitting need not be used. Unfortunately, a damp location is still subject to moderate amount of moisture (see 100: Definitions, Location Damp) and 314.15 states, "...fittings shall be placed or equipped so as to prevent moisture from entering or accumulating within the box, conduit body, or fitting."

 

[danger30]

Does 314 supercede 312 or is it an entirely different section? I believe it is the latter.

 

[Smart $]

Does 314 supercede 312 or is it an entirely different section? I believe it is the latter.

It is rather obvious it is a different section, is it not?

Superceding is in regards to the fitting (not the section of Code) used at the transition, as both sections have requirements for such.

 

[infinity]

Does 314 supercede 312 or is it an entirely different section? I believe it is the latter.

IMO the latter. You can come out of the bottom of a meter enclosure with a standard fitting such as a squeeze type SE connector.

 

[danger30]

Could you use the same type of connector in the bottom side factory knockout? While it's probably not a good idea, I don't see where 312 prohibits it. (As long as it's below live parts) IMO they should take out the verbiage in 312 about the live parts and make it the same as 314. (connectors suitable for the location)

 

[Smart $]

IMO the latter. You can come out of the bottom of a meter enclosure with a standard fitting such as a squeeze type SE connector.

Where in 312.2 does it say you don't have to use a wet-location listed connector in the bottom. Sure it says you have to use one above the lowest level of uninsulated live parts, but it doesn't say you don't have to use one at or below that level, does it?

Logical deduction (in other words, it is implied) by that section that wet-listed connectors are not required at or below that level, but only when you isolate that section as an only requirement. Yet it is not the only requirement that applies. Bottom of a meter enclosure outside is no less than a damp location. 314.15 would apply to fittings used there.

 

[Smart $]

Could you use the same type of connector in the bottom side factory knockout? While it's probably not a good idea, I don't see where 312 prohibits it. (As long as it's below live parts) IMO they should take out the verbiage in 312 about the live parts and make it the same as 314. (connectors suitable for the location)

Or at the very least, make the requirements correlate to each other...

I guess the technical correlating committee was asleep on this one