box inside a box?? for site lighting

[timceps]

We are using an open bottom brooks box with traffic rated cover for site lighting circuit terminations, pvc conduits stub up in bottom, inspector say's code requires a pvc box be installed within the brooks box for wire terminations citing 300-12, 300-15, 300-18. We are using weather proof splice kits for terminations. I do not see how the code articles he cites requires the box within a box for wire splices.

[ August 12, 2003, 12:02 PM: Message edited by: timceps ]

 

[iwire]

Re: box inside a box?? for site lighting

I have seen some handouts on this and it seems the "open bottom brooks box" is not a UL listed enclosure for conductors so you would need a box inside to comply.

That said I have only done this once and I have never seen others do it.

Bob

 

[iwire]

Re: box inside a box?? for site lighting

Here is one of the documents I saw this referenced in, and a link to where it came from, you will need Adobe reader to view it.

From the State of Washington's "Electrical Currents" put of by the Dept. of Labor

Wet Location Splices in Well Heads, Septic Tanks, and Open Bottom Handholes

Well heads and septic tanks are wet locations and require splices that are suitable for wet locations. Splices made in open bottom handholes/boxes are required to be suitable for direct burial. If the handhole/box is manufactured specifically for electrical use, splices approved for wet locations will be permitted under the following conditions in

WAC 296-46-370:

(1) The box shall be rated for not less than H-10 loading (8000 pounds over a 10" x 10" area) and be provided with a bolted, hinged, or slide-on lid embossed with the identification "ELECTRIC" or "ELECTRICAL." Metal covers shall be grounded per NEC Article 250.

(2) All conductors must be installed in approved electrical raceways which enter vertically from the open bottom of the enclosure. These raceways shall be fitted with a bushing, terminal fitting, or seal incorporating the physical protection characteristics of a bushing, and project not less than 2 inches (5 cm) above the bottom surface material. The bottom surface material shall be pea gravel, sand, or concrete.

It is important to remember that wire and splices in an open bottom handhole/box are considered to be direct burial requiring direct burial cable and splices unless it meets the requirements of (1) and (2) above that would allow wet location wire and splices. It should be noted that standard wire nuts are not approved for wet locations.

http://www.lni.wa.gov/scs/electrical/currents/elc99_7.pdf


Bob

 

[tom baker]

Re: box inside a box?? for site lighting

Its interesting to note the open bottom type TS handholes are not a recognized wiring method in the NEC, as there is a proposal for adding such a method in the 2005 NEC.
However Washington State does recognize that type installation and has a adminstrative rule to cover open bottom handholes.