Underground Junction Box UNDERGROUND JUNCTION BOX
Part 1 — General
1.1 Section Includes
A.Polymer concrete t ype I, II, and III junction boxes, concrete collars, ground rods, and utility marker posts.
B.Composite plastic type II and III junction boxes, concrete collars, ground rods, and utility marker posts.
1.2 Related Sections
A.Section 02056: Embankment, Borrow, and Backfill
B.Section 03055: Portland Cement Concrete
C.Section 03152: Concrete Joint Control
D.Section 16530: Electrical Power
1.3 References
A.ASTM C 1107: Packaged Dry, Hydraulic -Cement Grout (Nonshrink)
B.ASTM D 412: Vulcanized Rubber and Thermoplastic Elastomers - Tension
C.American National Standards Institute (ANSI)
D.Society of Cable Telecommunications Engineers (SCTE) Standards
E.USDA Rural Utilities Service (RUS) Specifications
1.4 DEFINITIONS Not Used
Underground Junction Box
1.5 Submittals
A.Junction box manufacturer’s data sheet for information.
B.Sealant manufacturer’s data sheet for information.
Part 2 — Products
2.1 Backfill
A.Free draining granular backfill – Refer to Section 02056 .
B.Sand
1.Friable natural river or bank aggregate, free of loam, detrimental, or soluble or organic matter 2. 3/8 inch minus, well graded
2.2 Junction Box and Lid
A.Junction box – Refer to AT Series Standard Drawings for dimensions of junction box types.
1.Meets all requirements of ANSI/SCTE 77 and Tier 22 loading
a.Include visible Tier 22 label.
2.Pre-cast polymer concrete or monolithic composite plastic
B.Lid
1.Meets all requirements of ANSI/SCTE 77 and Tier 22 loading
a.Include visible Tier 22 label.
2.Skid-resistant surface.
3.Lid Label
a.Determine the applicable lid label using the Junction Box Decision Chart. Refer to: http://www.udot.utah.gov/go/standardsreferences
b.Lid can be labeled using one of the following options: 1) Recessed 1 inch cast -in-place letters in the logo area centered on the lid 2) Recessed logo area 3 ¾ inch x 7 ¾ inch to accommodate name plate
4.Lid access points are recessed reinforced steel pull slots rated to at least 3000 lbs .
5.Lid bolt holes are self -draining.
6.Type III junction box lids are split into two pieces . Underground Junction Box
C.Bolts – ½ inch diameter z inc-plated, recessed hex head coil bolts with washer .
2.3 Name Plate Adhesive
A.Use an adhesive that is compatible with the lid material and meets or exceeds the following criteria:
1.Tensile Strength: 1200 psi
2.Service temperature, cured: - 20 degrees F to 140 degrees F
3.Cure time: 24 hours
2.4 Utility Marker Post
A.Refer to AT Series Standard Drawings.
B.Color
1.Red at electrical junction boxes
2.Orange at fiber optic and ITS junction boxes
C.Dome Type
1.Use in unstable soil or solid rock
2.3-inch diameter, 6 ft long
3.6-inch yellow retroreflective tape, ASTM Type III minimum
D.Flat Type
1.Use in poundable soil
2.Fiberglass
3.4 inch wide, 6 ft long
4.3 inch x 24 inch yellow retroreflective tape, ASTM Type III minimum
2.5 Ground Rod
A.Ground Rod – Refer to Section 16530.
2.6 Wiring
A.Grounding Conductor – Refer to Section 16530 .
2.7 Junction Box Wall Repair
A.Underground Junction Box
1.Dry pack, non -shrink grout according to ASTM C 1107 Underground Junction Box
B.Composite Plastic Junction Box
1.Plastic compatible sealant . Refer to ASTM D 412
a.Tensile Strength: 1200 psi
b.Cure temperature: 0 degrees F – 140 degrees F
c.Maximum Full Cure Time: 24 hours
2.8 Concrete Collar
A.Class B(AE) concrete or better – Refer to Section 03055.
2.9 Expansion Joint Material
A.Premolded joint filler , ½ inch . Refer to AT Series Standard Drawings and Section 03152.
2.10 Locate Ball Or Disk
A.Color
1.Red in electrical junction boxes
2.Orange in fiber optic and ITS junction boxes
B.Does not r equire a particular orientation when buried
C.Produces a uniform, spherical radio frequency field in all directions
D.Signal peak s when directly over the ball
E.Meets RUS Specifications
Part 3 — Execution
3.1 Backfill
A.Place 12 inch of free draining granular backfill under junction boxes.
B.Match the top 6 inch to the composition, density, and elevation of the surrounding surface around the junction box collar .
3.2 Junction Box
A.Install according to manufacturer’s recommendations.
B.Do not place junction boxes in roadway. Underground Junction Box
C.Install ½ inch pre molded joint filler around perimeter of junction box .
D.Cast in place 1 inch thick grout floor with a 1 inch diameter drain at the low point, or provide a box with a prefabricated floor with a 1 inch drain hole.
E.Do not stack boxes to bring the lid to final grade.
F.Provide precast junction boxes with precast conduit holes or drill holes to match conduit entry where required without damaging the box.
1.Drill holes in junction box no more than ¼ inch larger than the conduit diameter and at least 2 inch from the junction box corners.
2.Create a complete seal between conduit and the junction box wall with grout or sealant .
a.Finish grout or sealant smooth and flush with the interior wall.
G.Refer to AT Series Standard Drawings.
3.3 Junction Box Lid Name Plate
A.Attach name plate to recessed logo area using adhesive and non-corroding screws.
3.4 Concrete Collar
A.Refer to AT Series Standard Drawings.
B.Concrete B(AE) – Refer to Section 03055.
C.Install concrete collars around junction boxes except where junction boxes are surrounded by at least 10 inch of concrete flatwork .
3.5 Ground Rod
A.Refer to Section 16530 .
B.Attach splice enclosure to the ground rod with a ground conductor if armored fiber is present .
3.6 Locate Ball Or Disk
A.Place locate ball or disk in each junction box or on the bottom of the lid.
Source: Utah Standard Specifications for Road and Bridge Construction, 2026 Edition. Pages 1232–1236 of 1,331.